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kewei
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# Chapter 5: 使用未标记数据进行预训练
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- [ch05.ipynb](ch05.ipynb) 本章所有代码
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- [previous_chapters.py](previous_chapters.py) 在前面章节中的包含 `MultiHeadAttention`的python代码模块，在这里的未标记数据模型预训练过程中我们会用到它
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- [train.py](train.py) 一个独立的python脚本文件，包含我们在[ch05.ipynb](ch05.ipynb)中实现的GPT模型训练部分代码
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- [generate.py](generate.py) 一个独立的python脚本文件，包含我们在[ch05.ipynb](ch05.ipynb)中实现的GPT模型权重加载和应用代码
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import os
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import requests
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import json
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import numpy as np
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import tensorflow as tf
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from tqdm import tqdm
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def download_and_load_gpt2(model_size, models_dir):
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# Validate model size
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allowed_sizes = ("124M", "355M", "774M", "1558M")
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if model_size not in allowed_sizes:
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raise ValueError(f"Model size not in {allowed_sizes}")
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# Define paths
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model_dir = os.path.join(models_dir, model_size)
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base_url = "https://openaipublic.blob.core.windows.net/gpt-2/models"
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filenames = [
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"checkpoint", "encoder.json", "hparams.json",
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"model.ckpt.data-00000-of-00001", "model.ckpt.index",
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"model.ckpt.meta", "vocab.bpe"
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]
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# Download files
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os.makedirs(model_dir, exist_ok=True)
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for filename in filenames:
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file_url = os.path.join(base_url, model_size, filename)
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file_path = os.path.join(model_dir, filename)
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download_file(file_url, file_path)
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# Load hparams and params
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tf_ckpt_path = tf.train.latest_checkpoint(model_dir)
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hparams = json.load(open(os.path.join(model_dir, "hparams.json")))
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params = load_gpt2_params_from_tf_ckpt(tf_ckpt_path, hparams)
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return hparams, params
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def download_file(url, destination):
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# Send a GET request to download the file in streaming mode
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response = requests.get(url, stream=True)
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# Get the total file size from headers, defaulting to 0 if not present
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file_size = int(response.headers.get("content-length", 0))
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# Check if file exists and has the same size
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if os.path.exists(destination):
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file_size_local = os.path.getsize(destination)
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if file_size == file_size_local:
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print(f"File already exists and is up-to-date: {destination}")
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return
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# Define the block size for reading the file
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block_size = 1024 # 1 Kilobyte
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# Initialize the progress bar with total file size
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progress_bar_description = url.split("/")[-1] # Extract filename from URL
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with tqdm(total=file_size, unit="iB", unit_scale=True, desc=progress_bar_description) as progress_bar:
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# Open the destination file in binary write mode
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with open(destination, "wb") as file:
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# Iterate over the file data in chunks
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for chunk in response.iter_content(block_size):
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progress_bar.update(len(chunk)) # Update progress bar
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file.write(chunk) # Write the chunk to the file
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def load_gpt2_params_from_tf_ckpt(ckpt_path, hparams):
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# Initialize parameters dictionary with empty blocks for each layer
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params = {"blocks": [{} for _ in range(hparams["n_layer"])]}
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# Iterate over each variable in the checkpoint
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for name, _ in tf.train.list_variables(ckpt_path):
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# Load the variable and remove singleton dimensions
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variable_array = np.squeeze(tf.train.load_variable(ckpt_path, name))
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# Process the variable name to extract relevant parts
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variable_name_parts = name.split("/")[1:] # Skip the 'model/' prefix
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# Identify the target dictionary for the variable
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target_dict = params
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if variable_name_parts[0].startswith("h"):
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layer_number = int(variable_name_parts[0][1:])
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target_dict = params["blocks"][layer_number]
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# Recursively access or create nested dictionaries
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for key in variable_name_parts[1:-1]:
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target_dict = target_dict.setdefault(key, {})
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# Assign the variable array to the last key
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last_key = variable_name_parts[-1]
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target_dict[last_key] = variable_array
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return params
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# Copyright (c) Sebastian Raschka under Apache License 2.0 (see LICENSE.txt).
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# Source for "Build a Large Language Model From Scratch"
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# - https://www.manning.com/books/build-a-large-language-model-from-scratch
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# Code: https://github.com/rasbt/LLMs-from-scratch
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import json
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import numpy as np
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import os
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import requests
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import tensorflow as tf
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import tiktoken
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import torch
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from tqdm import tqdm
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# Import from local files
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from previous_chapters import GPTModel
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def text_to_token_ids(text, tokenizer):
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encoded = tokenizer.encode(text)
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encoded_tensor = torch.tensor(encoded).unsqueeze(0) # add batch dimension
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return encoded_tensor
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def token_ids_to_text(token_ids, tokenizer):
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flat = token_ids.squeeze(0) # remove batch dimension
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return tokenizer.decode(flat.tolist())
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def download_and_load_gpt2(model_size, models_dir):
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# Validate model size
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allowed_sizes = ("124M", "355M", "774M", "1558M")
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if model_size not in allowed_sizes:
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raise ValueError(f"Model size not in {allowed_sizes}")
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# Define paths
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model_dir = os.path.join(models_dir, model_size)
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base_url = "https://openaipublic.blob.core.windows.net/gpt-2/models"
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filenames = [
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"checkpoint", "encoder.json", "hparams.json",
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"model.ckpt.data-00000-of-00001", "model.ckpt.index",
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"model.ckpt.meta", "vocab.bpe"
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]
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# Download files
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os.makedirs(model_dir, exist_ok=True)
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for filename in filenames:
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file_url = os.path.join(base_url, model_size, filename)
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file_path = os.path.join(model_dir, filename)
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download_file(file_url, file_path)
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# Load hparams and params
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tf_ckpt_path = tf.train.latest_checkpoint(model_dir)
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hparams = json.load(open(os.path.join(model_dir, "hparams.json")))
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params = load_gpt2_params_from_tf_ckpt(tf_ckpt_path, hparams)
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return hparams, params
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def download_file(url, destination):
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# Send a GET request to download the file in streaming mode
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response = requests.get(url, stream=True)
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# Get the total file size from headers, defaulting to 0 if not present
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file_size = int(response.headers.get("content-length", 0))
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# Check if file exists and has the same size
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if os.path.exists(destination):
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file_size_local = os.path.getsize(destination)
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if file_size == file_size_local:
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print(f"File already exists and is up-to-date: {destination}")
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return
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# Define the block size for reading the file
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block_size = 1024 # 1 Kilobyte
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# Initialize the progress bar with total file size
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progress_bar_description = url.split("/")[-1] # Extract filename from URL
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with tqdm(total=file_size, unit="iB", unit_scale=True, desc=progress_bar_description) as progress_bar:
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# Open the destination file in binary write mode
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with open(destination, "wb") as file:
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# Iterate over the file data in chunks
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for chunk in response.iter_content(block_size):
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progress_bar.update(len(chunk)) # Update progress bar
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file.write(chunk) # Write the chunk to the file
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def load_gpt2_params_from_tf_ckpt(ckpt_path, hparams):
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# Initialize parameters dictionary with empty blocks for each layer
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params = {"blocks": [{} for _ in range(hparams["n_layer"])]}
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# Iterate over each variable in the checkpoint
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for name, _ in tf.train.list_variables(ckpt_path):
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# Load the variable and remove singleton dimensions
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variable_array = np.squeeze(tf.train.load_variable(ckpt_path, name))
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# Process the variable name to extract relevant parts
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variable_name_parts = name.split("/")[1:] # Skip the 'model/' prefix
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# Identify the target dictionary for the variable
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target_dict = params
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if variable_name_parts[0].startswith("h"):
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layer_number = int(variable_name_parts[0][1:])
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target_dict = params["blocks"][layer_number]
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# Recursively access or create nested dictionaries
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for key in variable_name_parts[1:-1]:
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target_dict = target_dict.setdefault(key, {})
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# Assign the variable array to the last key
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last_key = variable_name_parts[-1]
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target_dict[last_key] = variable_array
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return params
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def assign(left, right):
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if left.shape != right.shape:
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raise ValueError(f"Shape mismatch. Left: {left.shape}, Right: {right.shape}")
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return torch.nn.Parameter(torch.tensor(right))
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def load_weights_into_gpt(gpt, params):
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# Weight tying
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gpt.pos_emb.weight = assign(gpt.pos_emb.weight, params['wpe'])
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gpt.tok_emb.weight = assign(gpt.tok_emb.weight, params['wte'])
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for b in range(len(params["blocks"])):
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q_w, k_w, v_w = np.split((params["blocks"][b]["attn"]["c_attn"])["w"], 3, axis=-1)
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gpt.trf_blocks[b].att.W_query.weight = assign(gpt.trf_blocks[b].att.W_query.weight, q_w.T)
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gpt.trf_blocks[b].att.W_key.weight = assign(gpt.trf_blocks[b].att.W_key.weight, k_w.T)
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gpt.trf_blocks[b].att.W_value.weight = assign(gpt.trf_blocks[b].att.W_value.weight, v_w.T)
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q_b, k_b, v_b = np.split((params["blocks"][b]["attn"]["c_attn"])["b"], 3, axis=-1)
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gpt.trf_blocks[b].att.W_query.bias = assign(gpt.trf_blocks[b].att.W_query.bias, q_b)
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gpt.trf_blocks[b].att.W_key.bias = assign(gpt.trf_blocks[b].att.W_key.bias, k_b)
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gpt.trf_blocks[b].att.W_value.bias = assign(gpt.trf_blocks[b].att.W_value.bias, v_b)
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gpt.trf_blocks[b].att.out_proj.weight = assign(gpt.trf_blocks[b].att.out_proj.weight, params["blocks"][b]["attn"]["c_proj"]["w"].T)
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gpt.trf_blocks[b].att.out_proj.bias = assign(gpt.trf_blocks[b].att.out_proj.bias, params["blocks"][b]["attn"]["c_proj"]["b"])
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gpt.trf_blocks[b].ff.layers[0].weight = assign(gpt.trf_blocks[b].ff.layers[0].weight, params["blocks"][b]["mlp"]["c_fc"]["w"].T)
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gpt.trf_blocks[b].ff.layers[0].bias = assign(gpt.trf_blocks[b].ff.layers[0].bias, params["blocks"][b]["mlp"]["c_fc"]["b"])
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gpt.trf_blocks[b].ff.layers[2].weight = assign(gpt.trf_blocks[b].ff.layers[2].weight, params["blocks"][b]["mlp"]["c_proj"]["w"].T)
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gpt.trf_blocks[b].ff.layers[2].bias = assign(gpt.trf_blocks[b].ff.layers[2].bias, params["blocks"][b]["mlp"]["c_proj"]["b"])
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gpt.trf_blocks[b].norm1.scale = assign(gpt.trf_blocks[b].norm1.scale, params["blocks"][b]["ln_1"]["g"])
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gpt.trf_blocks[b].norm1.shift = assign(gpt.trf_blocks[b].norm1.shift, params["blocks"][b]["ln_1"]["b"])
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gpt.trf_blocks[b].norm2.scale = assign(gpt.trf_blocks[b].norm2.scale, params["blocks"][b]["ln_2"]["g"])
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gpt.trf_blocks[b].norm2.shift = assign(gpt.trf_blocks[b].norm2.shift, params["blocks"][b]["ln_2"]["b"])
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gpt.final_norm.scale = assign(gpt.final_norm.scale, params["g"])
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gpt.final_norm.shift = assign(gpt.final_norm.shift, params["b"])
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gpt.out_head.weight = assign(gpt.out_head.weight, params["wte"])
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def generate(model, idx, max_new_tokens, context_size, temperature, top_k=None):
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# For-loop is the same as before: Get logits, and only focus on last time step
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for _ in range(max_new_tokens):
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idx_cond = idx[:, -context_size:]
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with torch.no_grad():
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logits = model(idx_cond)
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logits = logits[:, -1, :]
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# New: Filter logits with top_k sampling
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if top_k is not None:
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# Keep only top_k values
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top_logits, _ = torch.topk(logits, top_k)
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min_val = top_logits[:, -1]
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logits = torch.where(logits < min_val, torch.tensor(float('-inf')).to(logits.device), logits)
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# New: Apply temperature scaling
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if temperature > 0.0:
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logits = logits / temperature
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# Apply softmax to get probabilities
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probs = torch.softmax(logits, dim=-1) # (batch_size, context_len)
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# Sample from the distribution
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idx_next = torch.multinomial(probs, num_samples=1) # (batch_size, 1)
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# Otherwise same as before: get idx of the vocab entry with the highest logits value
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else:
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idx_next = torch.argmax(logits, dim=-1, keepdim=True) # (batch_size, 1)
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# Same as before: append sampled index to the running sequence
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idx = torch.cat((idx, idx_next), dim=1) # (batch_size, num_tokens+1)
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return idx
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def main(gpt_config, input_prompt, model_size):
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device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
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hparams, params = download_and_load_gpt2(model_size=model_size, models_dir="gpt2")
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gpt = GPTModel(gpt_config)
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load_weights_into_gpt(gpt, params)
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gpt.to(device)
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gpt.eval()
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tokenizer = tiktoken.get_encoding("gpt2")
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token_ids = generate(
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model=gpt,
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idx=text_to_token_ids(input_prompt, tokenizer),
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max_new_tokens=30,
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context_size=gpt_config["ctx_len"],
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top_k=1,
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temperature=1.0
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)
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print("Output text:\n", token_ids_to_text(token_ids, tokenizer))
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if __name__ == "__main__":
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torch.manual_seed(123)
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CHOOSE_MODEL = "gpt2-small"
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INPUT_PROMPT = "Every effort moves"
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BASE_CONFIG = {
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"vocab_size": 50257, # Vocabulary size
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"ctx_len": 1024, # Context length
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"drop_rate": 0.0, # Dropout rate
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"qkv_bias": True # Query-key-value bias
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}
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model_configs = {
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"gpt2-small": {"emb_dim": 768, "n_layers": 12, "n_heads": 12},
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"gpt2-medium": {"emb_dim": 1024, "n_layers": 24, "n_heads": 16},
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"gpt2-large": {"emb_dim": 1280, "n_layers": 36, "n_heads": 20},
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"gpt2-xl": {"emb_dim": 1600, "n_layers": 48, "n_heads": 25},
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}
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model_sizes = {
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"gpt2-small": "124M",
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"gpt2-medium": "355M",
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"gpt2-large": "774M",
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"gpt2-xl": "1558"
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}
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BASE_CONFIG.update(model_configs[CHOOSE_MODEL])
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main(BASE_CONFIG, INPUT_PROMPT, model_sizes[CHOOSE_MODEL])
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@@ -0,0 +1,234 @@
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# Copyright (c) Sebastian Raschka under Apache License 2.0 (see LICENSE.txt).
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# Source for "Build a Large Language Model From Scratch"
|
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# - https://www.manning.com/books/build-a-large-language-model-from-scratch
|
||||
# Code: https://github.com/rasbt/LLMs-from-scratch
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import matplotlib.pyplot as plt
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import os
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import torch
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import urllib.request
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# Import from local files
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from previous_chapters import GPTModel, create_dataloader_v1, generate_text_simple
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||||
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||||
def text_to_token_ids(text, tokenizer):
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encoded = tokenizer.encode(text)
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||||
encoded_tensor = torch.tensor(encoded).unsqueeze(0) # add batch dimension
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return encoded_tensor
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def token_ids_to_text(token_ids, tokenizer):
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flat = token_ids.squeeze(0) # remove batch dimension
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return tokenizer.decode(flat.tolist())
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def calc_loss_batch(input_batch, target_batch, model, device):
|
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input_batch, target_batch = input_batch.to(device), target_batch.to(device)
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logits = model(input_batch)
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loss = torch.nn.functional.cross_entropy(logits.flatten(0, 1), target_batch.flatten())
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return loss
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||||
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def calc_loss_loader(data_loader, model, device, num_batches=None):
|
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total_loss = 0.
|
||||
if num_batches is None:
|
||||
num_batches = len(data_loader)
|
||||
else:
|
||||
num_batches = min(num_batches, len(data_loader))
|
||||
for i, (input_batch, target_batch) in enumerate(data_loader):
|
||||
if i < num_batches:
|
||||
loss = calc_loss_batch(input_batch, target_batch, model, device)
|
||||
total_loss += loss.item()
|
||||
else:
|
||||
break
|
||||
return total_loss / num_batches
|
||||
|
||||
|
||||
def evaluate_model(model, train_loader, val_loader, device, eval_iter):
|
||||
model.eval()
|
||||
with torch.no_grad():
|
||||
train_loss = calc_loss_loader(train_loader, model, device, num_batches=eval_iter)
|
||||
val_loss = calc_loss_loader(val_loader, model, device, num_batches=eval_iter)
|
||||
model.train()
|
||||
return train_loss, val_loss
|
||||
|
||||
|
||||
def generate_and_print_sample(model, tokenizer, device, start_context):
|
||||
model.eval()
|
||||
context_size = model.pos_emb.weight.shape[0]
|
||||
encoded = text_to_token_ids(start_context, tokenizer).to(device)
|
||||
with torch.no_grad():
|
||||
token_ids = generate_text_simple(
|
||||
model=model, idx=encoded,
|
||||
max_new_tokens=50, context_size=context_size
|
||||
)
|
||||
decoded_text = token_ids_to_text(token_ids, tokenizer)
|
||||
print(decoded_text.replace("\n", " ")) # Compact print format
|
||||
model.train()
|
||||
|
||||
|
||||
def train_model_simple(model, train_loader, val_loader, optimizer, device, num_epochs,
|
||||
eval_freq, eval_iter, start_context):
|
||||
# Initialize lists to track losses and tokens seen
|
||||
train_losses, val_losses, track_tokens_seen = [], [], []
|
||||
tokens_seen = 0
|
||||
global_step = -1
|
||||
|
||||
# Main training loop
|
||||
for epoch in range(num_epochs):
|
||||
model.train() # Set model to training mode
|
||||
|
||||
for input_batch, target_batch in train_loader:
|
||||
optimizer.zero_grad() # Reset loss gradients from previous epoch
|
||||
loss = calc_loss_batch(input_batch, target_batch, model, device)
|
||||
loss.backward() # Calculate loss gradients
|
||||
optimizer.step() # Update model weights using loss gradients
|
||||
tokens_seen += input_batch.numel()
|
||||
global_step += 1
|
||||
|
||||
# Optional evaluation step
|
||||
if global_step % eval_freq == 0:
|
||||
train_loss, val_loss = evaluate_model(
|
||||
model, train_loader, val_loader, device, eval_iter)
|
||||
train_losses.append(train_loss)
|
||||
val_losses.append(val_loss)
|
||||
track_tokens_seen.append(tokens_seen)
|
||||
print(f"Ep {epoch+1} (Step {global_step:06d}): "
|
||||
f"Train loss {train_loss:.3f}, Val loss {val_loss:.3f}")
|
||||
|
||||
# Print a sample text after each epoch
|
||||
generate_and_print_sample(
|
||||
model, train_loader.dataset.tokenizer, device, start_context
|
||||
)
|
||||
|
||||
return train_losses, val_losses, track_tokens_seen
|
||||
|
||||
|
||||
def plot_losses(epochs_seen, tokens_seen, train_losses, val_losses):
|
||||
fig, ax1 = plt.subplots()
|
||||
|
||||
# Plot training and validation loss against epochs
|
||||
ax1.plot(epochs_seen, train_losses, label="Training loss")
|
||||
ax1.plot(epochs_seen, val_losses, linestyle="-.", label="Validation loss")
|
||||
ax1.set_xlabel("Epochs")
|
||||
ax1.set_ylabel("Loss")
|
||||
ax1.legend(loc="upper right")
|
||||
|
||||
# Create a second x-axis for tokens seen
|
||||
ax2 = ax1.twiny() # Create a second x-axis that shares the same y-axis
|
||||
ax2.plot(tokens_seen, train_losses, alpha=0) # Invisible plot for aligning ticks
|
||||
ax2.set_xlabel("Tokens seen")
|
||||
|
||||
fig.tight_layout() # Adjust layout to make room
|
||||
# plt.show()
|
||||
|
||||
|
||||
def main(gpt_config, hparams):
|
||||
|
||||
torch.manual_seed(123)
|
||||
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
|
||||
|
||||
##############################
|
||||
# Download data if necessary
|
||||
##############################
|
||||
|
||||
file_path = "the-verdict.txt"
|
||||
url = "https://raw.githubusercontent.com/rasbt/LLMs-from-scratch/main/ch02/01_main-chapter-code/the-verdict.txt"
|
||||
|
||||
if not os.path.exists(file_path):
|
||||
with urllib.request.urlopen(url) as response:
|
||||
text_data = response.read().decode('utf-8')
|
||||
with open(file_path, "w", encoding="utf-8") as file:
|
||||
file.write(text_data)
|
||||
else:
|
||||
with open(file_path, "r", encoding="utf-8") as file:
|
||||
text_data = file.read()
|
||||
|
||||
##############################
|
||||
# Initialize model
|
||||
##############################
|
||||
|
||||
model = GPTModel(gpt_config)
|
||||
model.to(device) # no assignment model = model.to(device) necessary for nn.Module classes
|
||||
optimizer = torch.optim.AdamW(
|
||||
model.parameters(), lr=hparams["learning_rate"], weight_decay=hparams["weight_decay"]
|
||||
)
|
||||
|
||||
##############################
|
||||
# Set up dataloaders
|
||||
##############################
|
||||
|
||||
# Train/validation ratio
|
||||
train_ratio = 0.90
|
||||
split_idx = int(train_ratio * len(text_data))
|
||||
|
||||
train_loader = create_dataloader_v1(
|
||||
text_data[:split_idx],
|
||||
batch_size=hparams["batch_size"],
|
||||
max_length=gpt_config["ctx_len"],
|
||||
stride=gpt_config["ctx_len"],
|
||||
drop_last=True,
|
||||
shuffle=True
|
||||
)
|
||||
|
||||
val_loader = create_dataloader_v1(
|
||||
text_data[split_idx:],
|
||||
batch_size=hparams["batch_size"],
|
||||
max_length=gpt_config["ctx_len"],
|
||||
stride=gpt_config["ctx_len"],
|
||||
drop_last=False,
|
||||
shuffle=False
|
||||
)
|
||||
|
||||
##############################
|
||||
# Train model
|
||||
##############################
|
||||
|
||||
train_losses, val_losses, tokens_seen = train_model_simple(
|
||||
model, train_loader, val_loader, optimizer, device,
|
||||
num_epochs=hparams["num_epochs"], eval_freq=5, eval_iter=1,
|
||||
start_context="Every effort moves you",
|
||||
)
|
||||
|
||||
return train_losses, val_losses, tokens_seen, model
|
||||
|
||||
|
||||
if __name__ == "__main__":
|
||||
|
||||
GPT_CONFIG_124M = {
|
||||
"vocab_size": 50257, # Vocabulary size
|
||||
"ctx_len": 256, # Shortened context length (orig: 1024)
|
||||
"emb_dim": 768, # Embedding dimension
|
||||
"n_heads": 12, # Number of attention heads
|
||||
"n_layers": 12, # Number of layers
|
||||
"drop_rate": 0.1, # Dropout rate
|
||||
"qkv_bias": False # Query-key-value bias
|
||||
}
|
||||
|
||||
OTHER_HPARAMS = {
|
||||
"learning_rate": 5e-4,
|
||||
"num_epochs": 10,
|
||||
"batch_size": 2,
|
||||
"weight_decay": 0.1
|
||||
}
|
||||
|
||||
###########################
|
||||
# Initiate training
|
||||
###########################
|
||||
|
||||
train_losses, val_losses, tokens_seen, model = main(GPT_CONFIG_124M, OTHER_HPARAMS)
|
||||
|
||||
###########################
|
||||
# After training
|
||||
###########################
|
||||
|
||||
# Plot results
|
||||
epochs_tensor = torch.linspace(0, OTHER_HPARAMS["num_epochs"], len(train_losses))
|
||||
plot_losses(epochs_tensor, tokens_seen, train_losses, val_losses)
|
||||
plt.savefig("loss.pdf")
|
||||
|
||||
# Save and load model
|
||||
torch.save(model.state_dict(), "model.pth")
|
||||
model = GPTModel(GPT_CONFIG_124M)
|
||||
model.load_state_dict(torch.load("model.pth"))
|
||||
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|
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|
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|
After Width: | Height: | Size: 59 KiB |
@@ -0,0 +1,276 @@
|
||||
# This file collects all the relevant code that we covered thus far
|
||||
# throughout Chapters 2-4.
|
||||
# This file can be run as a standalone script.
|
||||
|
||||
import tiktoken
|
||||
import torch
|
||||
import torch.nn as nn
|
||||
from torch.utils.data import Dataset, DataLoader
|
||||
|
||||
#####################################
|
||||
# Chapter 2
|
||||
#####################################
|
||||
|
||||
|
||||
class GPTDatasetV1(Dataset):
|
||||
def __init__(self, txt, tokenizer, max_length, stride):
|
||||
self.tokenizer = tokenizer
|
||||
self.input_ids = []
|
||||
self.target_ids = []
|
||||
|
||||
# Tokenize the entire text
|
||||
token_ids = tokenizer.encode(txt)
|
||||
|
||||
# Use a sliding window to chunk the book into overlapping sequences of max_length
|
||||
for i in range(0, len(token_ids) - max_length, stride):
|
||||
input_chunk = token_ids[i:i + max_length]
|
||||
target_chunk = token_ids[i + 1: i + max_length + 1]
|
||||
self.input_ids.append(torch.tensor(input_chunk))
|
||||
self.target_ids.append(torch.tensor(target_chunk))
|
||||
|
||||
def __len__(self):
|
||||
return len(self.input_ids)
|
||||
|
||||
def __getitem__(self, idx):
|
||||
return self.input_ids[idx], self.target_ids[idx]
|
||||
|
||||
|
||||
def create_dataloader_v1(txt, batch_size=4, max_length=256,
|
||||
stride=128, shuffle=True, drop_last=True):
|
||||
# Initialize the tokenizer
|
||||
tokenizer = tiktoken.get_encoding("gpt2")
|
||||
|
||||
# Create dataset
|
||||
dataset = GPTDatasetV1(txt, tokenizer, max_length, stride)
|
||||
|
||||
# Create dataloader
|
||||
dataloader = DataLoader(
|
||||
dataset, batch_size=batch_size, shuffle=shuffle, drop_last=drop_last)
|
||||
|
||||
return dataloader
|
||||
|
||||
|
||||
#####################################
|
||||
# Chapter 3
|
||||
#####################################
|
||||
class MultiHeadAttention(nn.Module):
|
||||
def __init__(self, d_in, d_out, block_size, dropout, num_heads, qkv_bias=False):
|
||||
super().__init__()
|
||||
assert d_out % num_heads == 0, "d_out must be divisible by n_heads"
|
||||
|
||||
self.d_out = d_out
|
||||
self.num_heads = num_heads
|
||||
self.head_dim = d_out // num_heads # Reduce the projection dim to match desired output dim
|
||||
|
||||
self.W_query = nn.Linear(d_in, d_out, bias=qkv_bias)
|
||||
self.W_key = nn.Linear(d_in, d_out, bias=qkv_bias)
|
||||
self.W_value = nn.Linear(d_in, d_out, bias=qkv_bias)
|
||||
self.out_proj = nn.Linear(d_out, d_out) # Linear layer to combine head outputs
|
||||
self.dropout = nn.Dropout(dropout)
|
||||
self.register_buffer('mask', torch.triu(torch.ones(block_size, block_size), diagonal=1))
|
||||
|
||||
def forward(self, x):
|
||||
b, num_tokens, d_in = x.shape
|
||||
|
||||
keys = self.W_key(x) # Shape: (b, num_tokens, d_out)
|
||||
queries = self.W_query(x)
|
||||
values = self.W_value(x)
|
||||
|
||||
# We implicitly split the matrix by adding a `num_heads` dimension
|
||||
# Unroll last dim: (b, num_tokens, d_out) -> (b, num_tokens, num_heads, head_dim)
|
||||
keys = keys.view(b, num_tokens, self.num_heads, self.head_dim)
|
||||
values = values.view(b, num_tokens, self.num_heads, self.head_dim)
|
||||
queries = queries.view(b, num_tokens, self.num_heads, self.head_dim)
|
||||
|
||||
# Transpose: (b, num_tokens, num_heads, head_dim) -> (b, num_heads, num_tokens, head_dim)
|
||||
keys = keys.transpose(1, 2)
|
||||
queries = queries.transpose(1, 2)
|
||||
values = values.transpose(1, 2)
|
||||
|
||||
# Compute scaled dot-product attention (aka self-attention) with a causal mask
|
||||
attn_scores = queries @ keys.transpose(2, 3) # Dot product for each head
|
||||
|
||||
# Original mask truncated to the number of tokens and converted to boolean
|
||||
mask_bool = self.mask.bool()[:num_tokens, :num_tokens]
|
||||
|
||||
# Use the mask to fill attention scores
|
||||
attn_scores.masked_fill_(mask_bool, -torch.inf)
|
||||
|
||||
attn_weights = torch.softmax(attn_scores / keys.shape[-1]**0.5, dim=-1)
|
||||
attn_weights = self.dropout(attn_weights)
|
||||
|
||||
# Shape: (b, num_tokens, num_heads, head_dim)
|
||||
context_vec = (attn_weights @ values).transpose(1, 2)
|
||||
|
||||
# Combine heads, where self.d_out = self.num_heads * self.head_dim
|
||||
context_vec = context_vec.reshape(b, num_tokens, self.d_out)
|
||||
context_vec = self.out_proj(context_vec) # optional projection
|
||||
|
||||
return context_vec
|
||||
|
||||
|
||||
#####################################
|
||||
# Chapter 4
|
||||
#####################################
|
||||
class LayerNorm(nn.Module):
|
||||
def __init__(self, emb_dim):
|
||||
super().__init__()
|
||||
self.eps = 1e-5
|
||||
self.scale = nn.Parameter(torch.ones(emb_dim))
|
||||
self.shift = nn.Parameter(torch.zeros(emb_dim))
|
||||
|
||||
def forward(self, x):
|
||||
mean = x.mean(dim=-1, keepdim=True)
|
||||
var = x.var(dim=-1, keepdim=True, unbiased=False)
|
||||
norm_x = (x - mean) / torch.sqrt(var + self.eps)
|
||||
return self.scale * norm_x + self.shift
|
||||
|
||||
|
||||
class GELU(nn.Module):
|
||||
def __init__(self):
|
||||
super().__init__()
|
||||
|
||||
def forward(self, x):
|
||||
return 0.5 * x * (1 + torch.tanh(
|
||||
torch.sqrt(torch.tensor(2.0 / torch.pi)) *
|
||||
(x + 0.044715 * torch.pow(x, 3))
|
||||
))
|
||||
|
||||
|
||||
class FeedForward(nn.Module):
|
||||
def __init__(self, cfg):
|
||||
super().__init__()
|
||||
self.layers = nn.Sequential(
|
||||
nn.Linear(cfg["emb_dim"], 4 * cfg["emb_dim"]),
|
||||
GELU(),
|
||||
nn.Linear(4 * cfg["emb_dim"], cfg["emb_dim"]),
|
||||
nn.Dropout(cfg["drop_rate"])
|
||||
)
|
||||
|
||||
def forward(self, x):
|
||||
return self.layers(x)
|
||||
|
||||
|
||||
class TransformerBlock(nn.Module):
|
||||
def __init__(self, cfg):
|
||||
super().__init__()
|
||||
self.att = MultiHeadAttention(
|
||||
d_in=cfg["emb_dim"],
|
||||
d_out=cfg["emb_dim"],
|
||||
block_size=cfg["ctx_len"],
|
||||
num_heads=cfg["n_heads"],
|
||||
dropout=cfg["drop_rate"],
|
||||
qkv_bias=cfg["qkv_bias"])
|
||||
self.ff = FeedForward(cfg)
|
||||
self.norm1 = LayerNorm(cfg["emb_dim"])
|
||||
self.norm2 = LayerNorm(cfg["emb_dim"])
|
||||
self.drop_resid = nn.Dropout(cfg["drop_rate"])
|
||||
|
||||
def forward(self, x):
|
||||
# Shortcut connection for attention block
|
||||
shortcut = x
|
||||
x = self.norm1(x)
|
||||
x = self.att(x) # Shape [batch_size, num_tokens, emb_size]
|
||||
x = self.drop_resid(x)
|
||||
x = x + shortcut # Add the original input back
|
||||
|
||||
# Shortcut connection for feed-forward block
|
||||
shortcut = x
|
||||
x = self.norm2(x)
|
||||
x = self.ff(x)
|
||||
x = self.drop_resid(x)
|
||||
x = x + shortcut # Add the original input back
|
||||
|
||||
return x
|
||||
|
||||
|
||||
class GPTModel(nn.Module):
|
||||
def __init__(self, cfg):
|
||||
super().__init__()
|
||||
self.tok_emb = nn.Embedding(cfg["vocab_size"], cfg["emb_dim"])
|
||||
self.pos_emb = nn.Embedding(cfg["ctx_len"], cfg["emb_dim"])
|
||||
self.drop_emb = nn.Dropout(cfg["drop_rate"])
|
||||
|
||||
self.trf_blocks = nn.Sequential(
|
||||
*[TransformerBlock(cfg) for _ in range(cfg["n_layers"])])
|
||||
|
||||
self.final_norm = LayerNorm(cfg["emb_dim"])
|
||||
self.out_head = nn.Linear(cfg["emb_dim"], cfg["vocab_size"], bias=False)
|
||||
|
||||
def forward(self, in_idx):
|
||||
batch_size, seq_len = in_idx.shape
|
||||
tok_embeds = self.tok_emb(in_idx)
|
||||
pos_embeds = self.pos_emb(torch.arange(seq_len, device=in_idx.device))
|
||||
x = tok_embeds + pos_embeds # Shape [batch_size, num_tokens, emb_size]
|
||||
x = self.drop_emb(x)
|
||||
x = self.trf_blocks(x)
|
||||
x = self.final_norm(x)
|
||||
logits = self.out_head(x)
|
||||
return logits
|
||||
|
||||
|
||||
def generate_text_simple(model, idx, max_new_tokens, context_size):
|
||||
# idx is (B, T) array of indices in the current context
|
||||
for _ in range(max_new_tokens):
|
||||
|
||||
# Crop current context if it exceeds the supported context size
|
||||
# E.g., if LLM supports only 5 tokens, and the context size is 10
|
||||
# then only the last 5 tokens are used as context
|
||||
idx_cond = idx[:, -context_size:]
|
||||
|
||||
# Get the predictions
|
||||
with torch.no_grad():
|
||||
logits = model(idx_cond)
|
||||
|
||||
# Focus only on the last time step
|
||||
# (batch, n_token, vocab_size) becomes (batch, vocab_size)
|
||||
logits = logits[:, -1, :]
|
||||
|
||||
# Get the idx of the vocab entry with the highest logits value
|
||||
idx_next = torch.argmax(logits, dim=-1, keepdim=True) # (batch, 1)
|
||||
|
||||
# Append sampled index to the running sequence
|
||||
idx = torch.cat((idx, idx_next), dim=1) # (batch, n_tokens+1)
|
||||
|
||||
return idx
|
||||
|
||||
|
||||
if __name__ == "__main__":
|
||||
|
||||
GPT_CONFIG_124M = {
|
||||
"vocab_size": 50257, # Vocabulary size
|
||||
"ctx_len": 1024, # Context length
|
||||
"emb_dim": 768, # Embedding dimension
|
||||
"n_heads": 12, # Number of attention heads
|
||||
"n_layers": 12, # Number of layers
|
||||
"drop_rate": 0.1, # Dropout rate
|
||||
"qkv_bias": False # Query-Key-Value bias
|
||||
}
|
||||
|
||||
torch.manual_seed(123)
|
||||
model = GPTModel(GPT_CONFIG_124M)
|
||||
model.eval() # disable dropout
|
||||
|
||||
start_context = "Hello, I am"
|
||||
|
||||
tokenizer = tiktoken.get_encoding("gpt2")
|
||||
encoded = tokenizer.encode(start_context)
|
||||
encoded_tensor = torch.tensor(encoded).unsqueeze(0)
|
||||
|
||||
print(f"\n{50*'='}\n{22*' '}IN\n{50*'='}")
|
||||
print("\nInput text:", start_context)
|
||||
print("Encoded input text:", encoded)
|
||||
print("encoded_tensor.shape:", encoded_tensor.shape)
|
||||
|
||||
out = generate_text_simple(
|
||||
model=model,
|
||||
idx=encoded_tensor,
|
||||
max_new_tokens=10,
|
||||
context_size=GPT_CONFIG_124M["ctx_len"]
|
||||
)
|
||||
decoded_text = tokenizer.decode(out.squeeze(0).tolist())
|
||||
|
||||
print(f"\n\n{50*'='}\n{22*' '}OUT\n{50*'='}")
|
||||
print("\nOutput:", out)
|
||||
print("Output length:", len(out[0]))
|
||||
print("Output text:", decoded_text)
|
||||
@@ -0,0 +1,40 @@
|
||||
# Copyright (c) Sebastian Raschka under Apache License 2.0 (see LICENSE.txt).
|
||||
# Source for "Build a Large Language Model From Scratch"
|
||||
# - https://www.manning.com/books/build-a-large-language-model-from-scratch
|
||||
# Code: https://github.com/rasbt/LLMs-from-scratch
|
||||
|
||||
# File for internal use (unit tests)
|
||||
|
||||
import pytest
|
||||
from gpt_train import main
|
||||
|
||||
|
||||
@pytest.fixture
|
||||
def gpt_config():
|
||||
return {
|
||||
"vocab_size": 50257,
|
||||
"ctx_len": 12, # small for testing efficiency
|
||||
"emb_dim": 32, # small for testing efficiency
|
||||
"n_heads": 4, # small for testing efficiency
|
||||
"n_layers": 2, # small for testing efficiency
|
||||
"drop_rate": 0.1,
|
||||
"qkv_bias": False
|
||||
}
|
||||
|
||||
|
||||
@pytest.fixture
|
||||
def other_hparams():
|
||||
return {
|
||||
"learning_rate": 5e-4,
|
||||
"num_epochs": 1, # small for testing efficiency
|
||||
"batch_size": 2,
|
||||
"weight_decay": 0.1
|
||||
}
|
||||
|
||||
|
||||
def test_main(gpt_config, other_hparams):
|
||||
train_losses, val_losses, tokens_seen, model = main(gpt_config, other_hparams)
|
||||
|
||||
assert len(train_losses) == 39, "Unexpected number of training losses"
|
||||
assert len(val_losses) == 39, "Unexpected number of validation losses"
|
||||
assert len(tokens_seen) == 39, "Unexpected number of tokens seen"
|
||||
@@ -0,0 +1,5 @@
|
||||
# Alternative Weight Loading
|
||||
|
||||
This folder contains alternative weight loading strategies in case the weights become unavailable from Open AI.
|
||||
|
||||
- [weight-loading-hf-transformers.ipynb](weight-loading-hf-transformers.ipynb): contains code to load the weights from the Hugging Face Model Hub via the `transformers` library
|
||||
@@ -0,0 +1,287 @@
|
||||
# This file collects all the relevant code that we covered thus far
|
||||
# throughout Chapters 2-4.
|
||||
# This file can be run as a standalone script.
|
||||
|
||||
import tiktoken
|
||||
import torch
|
||||
import torch.nn as nn
|
||||
from torch.utils.data import Dataset, DataLoader
|
||||
|
||||
#####################################
|
||||
# Chapter 2
|
||||
#####################################
|
||||
|
||||
|
||||
class GPTDatasetV1(Dataset):
|
||||
def __init__(self, txt, tokenizer, max_length, stride):
|
||||
self.tokenizer = tokenizer
|
||||
self.input_ids = []
|
||||
self.target_ids = []
|
||||
|
||||
# Tokenize the entire text
|
||||
token_ids = tokenizer.encode(txt)
|
||||
|
||||
# Use a sliding window to chunk the book into overlapping sequences of max_length
|
||||
for i in range(0, len(token_ids) - max_length, stride):
|
||||
input_chunk = token_ids[i:i + max_length]
|
||||
target_chunk = token_ids[i + 1: i + max_length + 1]
|
||||
self.input_ids.append(torch.tensor(input_chunk))
|
||||
self.target_ids.append(torch.tensor(target_chunk))
|
||||
|
||||
def __len__(self):
|
||||
return len(self.input_ids)
|
||||
|
||||
def __getitem__(self, idx):
|
||||
return self.input_ids[idx], self.target_ids[idx]
|
||||
|
||||
|
||||
def create_dataloader_v1(txt, batch_size=4, max_length=256,
|
||||
stride=128, shuffle=True, drop_last=True):
|
||||
# Initialize the tokenizer
|
||||
tokenizer = tiktoken.get_encoding("gpt2")
|
||||
|
||||
# Create dataset
|
||||
dataset = GPTDatasetV1(txt, tokenizer, max_length, stride)
|
||||
|
||||
# Create dataloader
|
||||
dataloader = DataLoader(
|
||||
dataset, batch_size=batch_size, shuffle=shuffle, drop_last=drop_last)
|
||||
|
||||
return dataloader
|
||||
|
||||
|
||||
#####################################
|
||||
# Chapter 3
|
||||
#####################################
|
||||
class MultiHeadAttention(nn.Module):
|
||||
def __init__(self, d_in, d_out, block_size, dropout, num_heads, qkv_bias=False):
|
||||
super().__init__()
|
||||
assert d_out % num_heads == 0, "d_out must be divisible by n_heads"
|
||||
|
||||
self.d_out = d_out
|
||||
self.num_heads = num_heads
|
||||
self.head_dim = d_out // num_heads # Reduce the projection dim to match desired output dim
|
||||
|
||||
self.W_query = nn.Linear(d_in, d_out, bias=qkv_bias)
|
||||
self.W_key = nn.Linear(d_in, d_out, bias=qkv_bias)
|
||||
self.W_value = nn.Linear(d_in, d_out, bias=qkv_bias)
|
||||
self.out_proj = nn.Linear(d_out, d_out) # Linear layer to combine head outputs
|
||||
self.dropout = nn.Dropout(dropout)
|
||||
self.register_buffer('mask', torch.triu(torch.ones(block_size, block_size), diagonal=1))
|
||||
|
||||
def forward(self, x):
|
||||
b, num_tokens, d_in = x.shape
|
||||
|
||||
keys = self.W_key(x) # Shape: (b, num_tokens, d_out)
|
||||
queries = self.W_query(x)
|
||||
values = self.W_value(x)
|
||||
|
||||
# We implicitly split the matrix by adding a `num_heads` dimension
|
||||
# Unroll last dim: (b, num_tokens, d_out) -> (b, num_tokens, num_heads, head_dim)
|
||||
keys = keys.view(b, num_tokens, self.num_heads, self.head_dim)
|
||||
values = values.view(b, num_tokens, self.num_heads, self.head_dim)
|
||||
queries = queries.view(b, num_tokens, self.num_heads, self.head_dim)
|
||||
|
||||
# Transpose: (b, num_tokens, num_heads, head_dim) -> (b, num_heads, num_tokens, head_dim)
|
||||
keys = keys.transpose(1, 2)
|
||||
queries = queries.transpose(1, 2)
|
||||
values = values.transpose(1, 2)
|
||||
|
||||
# Compute scaled dot-product attention (aka self-attention) with a causal mask
|
||||
attn_scores = queries @ keys.transpose(2, 3) # Dot product for each head
|
||||
|
||||
# Original mask truncated to the number of tokens and converted to boolean
|
||||
mask_bool = self.mask.bool()[:num_tokens, :num_tokens]
|
||||
|
||||
# Use the mask to fill attention scores
|
||||
attn_scores.masked_fill_(mask_bool, -torch.inf)
|
||||
|
||||
attn_weights = torch.softmax(attn_scores / keys.shape[-1]**0.5, dim=-1)
|
||||
attn_weights = self.dropout(attn_weights)
|
||||
|
||||
# Shape: (b, num_tokens, num_heads, head_dim)
|
||||
context_vec = (attn_weights @ values).transpose(1, 2)
|
||||
|
||||
# Combine heads, where self.d_out = self.num_heads * self.head_dim
|
||||
context_vec = context_vec.reshape(b, num_tokens, self.d_out)
|
||||
context_vec = self.out_proj(context_vec) # optional projection
|
||||
|
||||
return context_vec
|
||||
|
||||
|
||||
#####################################
|
||||
# Chapter 4
|
||||
#####################################
|
||||
class LayerNorm(nn.Module):
|
||||
def __init__(self, emb_dim):
|
||||
super().__init__()
|
||||
self.eps = 1e-5
|
||||
self.scale = nn.Parameter(torch.ones(emb_dim))
|
||||
self.shift = nn.Parameter(torch.zeros(emb_dim))
|
||||
|
||||
def forward(self, x):
|
||||
mean = x.mean(dim=-1, keepdim=True)
|
||||
var = x.var(dim=-1, keepdim=True, unbiased=False)
|
||||
norm_x = (x - mean) / torch.sqrt(var + self.eps)
|
||||
return self.scale * norm_x + self.shift
|
||||
|
||||
|
||||
class GELU(nn.Module):
|
||||
def __init__(self):
|
||||
super().__init__()
|
||||
|
||||
def forward(self, x):
|
||||
return 0.5 * x * (1 + torch.tanh(
|
||||
torch.sqrt(torch.tensor(2.0 / torch.pi)) *
|
||||
(x + 0.044715 * torch.pow(x, 3))
|
||||
))
|
||||
|
||||
|
||||
class FeedForward(nn.Module):
|
||||
def __init__(self, cfg):
|
||||
super().__init__()
|
||||
self.layers = nn.Sequential(
|
||||
nn.Linear(cfg["emb_dim"], 4 * cfg["emb_dim"]),
|
||||
GELU(),
|
||||
nn.Linear(4 * cfg["emb_dim"], cfg["emb_dim"]),
|
||||
nn.Dropout(cfg["drop_rate"])
|
||||
)
|
||||
|
||||
def forward(self, x):
|
||||
return self.layers(x)
|
||||
|
||||
|
||||
class TransformerBlock(nn.Module):
|
||||
def __init__(self, cfg):
|
||||
super().__init__()
|
||||
self.att = MultiHeadAttention(
|
||||
d_in=cfg["emb_dim"],
|
||||
d_out=cfg["emb_dim"],
|
||||
block_size=cfg["ctx_len"],
|
||||
num_heads=cfg["n_heads"],
|
||||
dropout=cfg["drop_rate"],
|
||||
qkv_bias=cfg["qkv_bias"])
|
||||
self.ff = FeedForward(cfg)
|
||||
self.norm1 = LayerNorm(cfg["emb_dim"])
|
||||
self.norm2 = LayerNorm(cfg["emb_dim"])
|
||||
self.drop_resid = nn.Dropout(cfg["drop_rate"])
|
||||
|
||||
def forward(self, x):
|
||||
# Shortcut connection for attention block
|
||||
shortcut = x
|
||||
x = self.norm1(x)
|
||||
x = self.att(x) # Shape [batch_size, num_tokens, emb_size]
|
||||
x = self.drop_resid(x)
|
||||
x = x + shortcut # Add the original input back
|
||||
|
||||
# Shortcut connection for feed-forward block
|
||||
shortcut = x
|
||||
x = self.norm2(x)
|
||||
x = self.ff(x)
|
||||
x = self.drop_resid(x)
|
||||
x = x + shortcut # Add the original input back
|
||||
|
||||
return x
|
||||
|
||||
|
||||
class GPTModel(nn.Module):
|
||||
def __init__(self, cfg):
|
||||
super().__init__()
|
||||
self.tok_emb = nn.Embedding(cfg["vocab_size"], cfg["emb_dim"])
|
||||
self.pos_emb = nn.Embedding(cfg["ctx_len"], cfg["emb_dim"])
|
||||
self.drop_emb = nn.Dropout(cfg["drop_rate"])
|
||||
|
||||
self.trf_blocks = nn.Sequential(
|
||||
*[TransformerBlock(cfg) for _ in range(cfg["n_layers"])])
|
||||
|
||||
self.final_norm = LayerNorm(cfg["emb_dim"])
|
||||
self.out_head = nn.Linear(cfg["emb_dim"], cfg["vocab_size"], bias=False)
|
||||
|
||||
def forward(self, in_idx):
|
||||
batch_size, seq_len = in_idx.shape
|
||||
tok_embeds = self.tok_emb(in_idx)
|
||||
pos_embeds = self.pos_emb(torch.arange(seq_len, device=in_idx.device))
|
||||
x = tok_embeds + pos_embeds # Shape [batch_size, num_tokens, emb_size]
|
||||
x = self.drop_emb(x)
|
||||
x = self.trf_blocks(x)
|
||||
x = self.final_norm(x)
|
||||
logits = self.out_head(x)
|
||||
return logits
|
||||
|
||||
|
||||
def generate_text_simple(model, idx, max_new_tokens, context_size):
|
||||
# idx is (B, T) array of indices in the current context
|
||||
for _ in range(max_new_tokens):
|
||||
|
||||
# Crop current context if it exceeds the supported context size
|
||||
# E.g., if LLM supports only 5 tokens, and the context size is 10
|
||||
# then only the last 5 tokens are used as context
|
||||
idx_cond = idx[:, -context_size:]
|
||||
|
||||
# Get the predictions
|
||||
with torch.no_grad():
|
||||
logits = model(idx_cond)
|
||||
|
||||
# Focus only on the last time step
|
||||
# (batch, n_token, vocab_size) becomes (batch, vocab_size)
|
||||
logits = logits[:, -1, :]
|
||||
|
||||
# Get the idx of the vocab entry with the highest logits value
|
||||
idx_next = torch.argmax(logits, dim=-1, keepdim=True) # (batch, 1)
|
||||
|
||||
# Append sampled index to the running sequence
|
||||
idx = torch.cat((idx, idx_next), dim=1) # (batch, n_tokens+1)
|
||||
|
||||
return idx
|
||||
|
||||
|
||||
#####################################
|
||||
# Chapter 5
|
||||
#####################################
|
||||
|
||||
|
||||
def text_to_token_ids(text, tokenizer):
|
||||
encoded = tokenizer.encode(text)
|
||||
encoded_tensor = torch.tensor(encoded).unsqueeze(0) # add batch dimension
|
||||
return encoded_tensor
|
||||
|
||||
|
||||
def token_ids_to_text(token_ids, tokenizer):
|
||||
flat = token_ids.squeeze(0) # remove batch dimension
|
||||
return tokenizer.decode(flat.tolist())
|
||||
|
||||
|
||||
def generate(model, idx, max_new_tokens, context_size, temperature, top_k=None):
|
||||
|
||||
# For-loop is the same as before: Get logits, and only focus on last time step
|
||||
for _ in range(max_new_tokens):
|
||||
idx_cond = idx[:, -context_size:]
|
||||
with torch.no_grad():
|
||||
logits = model(idx_cond)
|
||||
logits = logits[:, -1, :]
|
||||
|
||||
# New: Filter logits with top_k sampling
|
||||
if top_k is not None:
|
||||
# Keep only top_k values
|
||||
top_logits, _ = torch.topk(logits, top_k)
|
||||
min_val = top_logits[:, -1]
|
||||
logits = torch.where(logits < min_val, torch.tensor(float('-inf')).to(logits.device), logits)
|
||||
|
||||
# New: Apply temperature scaling
|
||||
if temperature > 0.0:
|
||||
logits = logits / temperature
|
||||
|
||||
# Apply softmax to get probabilities
|
||||
probs = torch.softmax(logits, dim=-1) # (batch_size, context_len)
|
||||
|
||||
# Sample from the distribution
|
||||
idx_next = torch.multinomial(probs, num_samples=1) # (batch_size, 1)
|
||||
|
||||
# Otherwise same as before: get idx of the vocab entry with the highest logits value
|
||||
else:
|
||||
idx_next = torch.argmax(logits, dim=-1, keepdim=True) # (batch_size, 1)
|
||||
|
||||
# Same as before: append sampled index to the running sequence
|
||||
idx = torch.cat((idx, idx_next), dim=1) # (batch_size, num_tokens+1)
|
||||
|
||||
return idx
|
||||
@@ -0,0 +1,312 @@
|
||||
{
|
||||
"cells": [
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"id": "6d6bc54f-2b16-4b0f-be69-957eed5d112f",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<font size=\"1\">\n",
|
||||
"Supplementary code for \"Build a Large Language Model From Scratch\": <a href=\"https://www.manning.com/books/build-a-large-language-model-from-scratch\">https://www.manning.com/books/build-a-large-language-model-from-scratch</a> by <a href=\"https://sebastianraschka.com\">Sebastian Raschka</a><br>\n",
|
||||
"Code repository: <a href=\"https://github.com/rasbt/LLMs-from-scratch\">https://github.com/rasbt/LLMs-from-scratch</a>\n",
|
||||
"</font>"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"id": "72953590-5363-4398-85ce-54bde07f3d8a",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"# Bonus Code for Chapter 5"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"id": "1a4ab5ee-e7b9-45d3-a82b-a12bcfc0945a",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"## Alternative Weight Loading from Hugging Face Model Hub using Transformers"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"id": "b2feea87-49f0-48b9-b925-b8f0dda4096f",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"- In the main chapter, we loaded the GPT model weights directly from OpenAI\n",
|
||||
"- This notebook provides alternative weight loading code to load the model weights from the [Hugging Face Model Hub](https://huggingface.co/docs/hub/en/models-the-hub) using the `transformers` Python library"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": 1,
|
||||
"id": "99b77109-5215-4d07-a618-4d10eff1a488",
|
||||
"metadata": {},
|
||||
"outputs": [],
|
||||
"source": [
|
||||
"# pip install transformers"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": 2,
|
||||
"id": "b0467eff-b43c-4a38-93e8-5ed87a5fc2b1",
|
||||
"metadata": {},
|
||||
"outputs": [
|
||||
{
|
||||
"name": "stdout",
|
||||
"output_type": "stream",
|
||||
"text": [
|
||||
"numpy version: 1.25.2\n",
|
||||
"torch version: 2.2.1\n",
|
||||
"transformers version: 4.33.2\n"
|
||||
]
|
||||
}
|
||||
],
|
||||
"source": [
|
||||
"from importlib.metadata import version\n",
|
||||
"\n",
|
||||
"pkgs = [\"numpy\", \"torch\", \"transformers\"]\n",
|
||||
"for p in pkgs:\n",
|
||||
" print(f\"{p} version: {version(p)}\")"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": 3,
|
||||
"id": "ffc17d7d-bcd8-42ee-82a9-04fd55acf15d",
|
||||
"metadata": {},
|
||||
"outputs": [
|
||||
{
|
||||
"name": "stderr",
|
||||
"output_type": "stream",
|
||||
"text": [
|
||||
"/Users/sebastian/miniforge3/envs/book/lib/python3.11/site-packages/transformers/utils/generic.py:311: UserWarning: torch.utils._pytree._register_pytree_node is deprecated. Please use torch.utils._pytree.register_pytree_node instead.\n",
|
||||
" torch.utils._pytree._register_pytree_node(\n",
|
||||
"/Users/sebastian/miniforge3/envs/book/lib/python3.11/site-packages/transformers/utils/generic.py:311: UserWarning: torch.utils._pytree._register_pytree_node is deprecated. Please use torch.utils._pytree.register_pytree_node instead.\n",
|
||||
" torch.utils._pytree._register_pytree_node(\n"
|
||||
]
|
||||
},
|
||||
{
|
||||
"data": {
|
||||
"text/plain": [
|
||||
"GPT2Model(\n",
|
||||
" (wte): Embedding(50257, 768)\n",
|
||||
" (wpe): Embedding(1024, 768)\n",
|
||||
" (drop): Dropout(p=0.1, inplace=False)\n",
|
||||
" (h): ModuleList(\n",
|
||||
" (0-11): 12 x GPT2Block(\n",
|
||||
" (ln_1): LayerNorm((768,), eps=1e-05, elementwise_affine=True)\n",
|
||||
" (attn): GPT2Attention(\n",
|
||||
" (c_attn): Conv1D()\n",
|
||||
" (c_proj): Conv1D()\n",
|
||||
" (attn_dropout): Dropout(p=0.1, inplace=False)\n",
|
||||
" (resid_dropout): Dropout(p=0.1, inplace=False)\n",
|
||||
" )\n",
|
||||
" (ln_2): LayerNorm((768,), eps=1e-05, elementwise_affine=True)\n",
|
||||
" (mlp): GPT2MLP(\n",
|
||||
" (c_fc): Conv1D()\n",
|
||||
" (c_proj): Conv1D()\n",
|
||||
" (act): NewGELUActivation()\n",
|
||||
" (dropout): Dropout(p=0.1, inplace=False)\n",
|
||||
" )\n",
|
||||
" )\n",
|
||||
" )\n",
|
||||
" (ln_f): LayerNorm((768,), eps=1e-05, elementwise_affine=True)\n",
|
||||
")"
|
||||
]
|
||||
},
|
||||
"execution_count": 3,
|
||||
"metadata": {},
|
||||
"output_type": "execute_result"
|
||||
}
|
||||
],
|
||||
"source": [
|
||||
"from transformers import GPT2Model\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"# allowed model names\n",
|
||||
"model_names = {\n",
|
||||
" \"gpt2-small\": \"openai-community/gpt2\", # 124M\n",
|
||||
" \"gpt2-medium\": \"openai-community/gpt2-medium\", # 355M\n",
|
||||
" \"gpt2-large\": \"openai-community/gpt2-large\", # 774M\n",
|
||||
" \"gpt2-xl\": \"openai-community/gpt2-xl\" # 1558M\n",
|
||||
"}\n",
|
||||
"\n",
|
||||
"CHOOSE_MODEL = \"gpt2-small\"\n",
|
||||
"\n",
|
||||
"gpt_hf = GPT2Model.from_pretrained(model_names[CHOOSE_MODEL], cache_dir=\"checkpoints\")\n",
|
||||
"gpt_hf.eval()"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": 4,
|
||||
"id": "9ea9b1bc-7881-46ad-9555-27a9cf23faa7",
|
||||
"metadata": {},
|
||||
"outputs": [],
|
||||
"source": [
|
||||
"BASE_CONFIG = {\n",
|
||||
" \"vocab_size\": 50257, # Vocabulary size\n",
|
||||
" \"ctx_len\": 1024, # Context length\n",
|
||||
" \"drop_rate\": 0.0, # Dropout rate\n",
|
||||
" \"qkv_bias\": True # Query-key-value bias\n",
|
||||
"}\n",
|
||||
"\n",
|
||||
"model_configs = {\n",
|
||||
" \"gpt2-small\": {\"emb_dim\": 768, \"n_layers\": 12, \"n_heads\": 12},\n",
|
||||
" \"gpt2-medium\": {\"emb_dim\": 1024, \"n_layers\": 24, \"n_heads\": 16},\n",
|
||||
" \"gpt2-large\": {\"emb_dim\": 1280, \"n_layers\": 36, \"n_heads\": 20},\n",
|
||||
" \"gpt2-xl\": {\"emb_dim\": 1600, \"n_layers\": 48, \"n_heads\": 25},\n",
|
||||
"}\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"BASE_CONFIG.update(model_configs[CHOOSE_MODEL])"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": 5,
|
||||
"id": "4e2a4cf4-a54e-4307-9141-fb9f288e4dfa",
|
||||
"metadata": {},
|
||||
"outputs": [],
|
||||
"source": [
|
||||
"def assign_check(left, right):\n",
|
||||
" if left.shape != right.shape:\n",
|
||||
" raise ValueError(f\"Shape mismatch. Left: {left.shape}, Right: {right.shape}\")\n",
|
||||
" return torch.nn.Parameter(torch.tensor(right))"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": 6,
|
||||
"id": "75be3077-f141-44bb-af88-62580ffd224c",
|
||||
"metadata": {},
|
||||
"outputs": [],
|
||||
"source": [
|
||||
"import numpy as np\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"def load_weights(gpt, gpt_hf):\n",
|
||||
"\n",
|
||||
" d = gpt_hf.state_dict()\n",
|
||||
"\n",
|
||||
" gpt.pos_emb.weight = assign_check(gpt.pos_emb.weight, d[\"wpe.weight\"])\n",
|
||||
" gpt.tok_emb.weight = assign_check(gpt.tok_emb.weight, d[\"wte.weight\"])\n",
|
||||
" \n",
|
||||
" for b in range(BASE_CONFIG[\"n_layers\"]):\n",
|
||||
" q_w, k_w, v_w = np.split(d[f\"h.{b}.attn.c_attn.weight\"], 3, axis=-1)\n",
|
||||
" gpt.trf_blocks[b].att.W_query.weight = assign_check(gpt.trf_blocks[b].att.W_query.weight, q_w.T)\n",
|
||||
" gpt.trf_blocks[b].att.W_key.weight = assign_check(gpt.trf_blocks[b].att.W_key.weight, k_w.T)\n",
|
||||
" gpt.trf_blocks[b].att.W_value.weight = assign_check(gpt.trf_blocks[b].att.W_value.weight, v_w.T)\n",
|
||||
" \n",
|
||||
" q_b, k_b, v_b = np.split(d[f\"h.{b}.attn.c_attn.bias\"], 3, axis=-1)\n",
|
||||
" gpt.trf_blocks[b].att.W_query.bias = assign_check(gpt.trf_blocks[b].att.W_query.bias, q_b)\n",
|
||||
" gpt.trf_blocks[b].att.W_key.bias = assign_check(gpt.trf_blocks[b].att.W_key.bias, k_b)\n",
|
||||
" gpt.trf_blocks[b].att.W_value.bias = assign_check(gpt.trf_blocks[b].att.W_value.bias, v_b)\n",
|
||||
" \n",
|
||||
" \n",
|
||||
" gpt.trf_blocks[b].att.out_proj.weight = assign_check(gpt.trf_blocks[b].att.out_proj.weight, d[f\"h.{b}.attn.c_proj.weight\"].T)\n",
|
||||
" gpt.trf_blocks[b].att.out_proj.bias = assign_check(gpt.trf_blocks[b].att.out_proj.bias, d[f\"h.{b}.attn.c_proj.bias\"])\n",
|
||||
" \n",
|
||||
" gpt.trf_blocks[b].ff.layers[0].weight = assign_check(gpt.trf_blocks[b].ff.layers[0].weight, d[f\"h.{b}.mlp.c_fc.weight\"].T)\n",
|
||||
" gpt.trf_blocks[b].ff.layers[0].bias = assign_check(gpt.trf_blocks[b].ff.layers[0].bias, d[f\"h.{b}.mlp.c_fc.bias\"])\n",
|
||||
" gpt.trf_blocks[b].ff.layers[2].weight = assign_check(gpt.trf_blocks[b].ff.layers[2].weight, d[f\"h.{b}.mlp.c_proj.weight\"].T)\n",
|
||||
" gpt.trf_blocks[b].ff.layers[2].bias = assign_check(gpt.trf_blocks[b].ff.layers[2].bias, d[f\"h.{b}.mlp.c_proj.bias\"])\n",
|
||||
" \n",
|
||||
" gpt.trf_blocks[b].norm1.scale = assign_check(gpt.trf_blocks[b].norm1.scale, d[f\"h.{b}.ln_1.weight\"])\n",
|
||||
" gpt.trf_blocks[b].norm1.shift = assign_check(gpt.trf_blocks[b].norm1.shift, d[f\"h.{b}.ln_1.bias\"])\n",
|
||||
" gpt.trf_blocks[b].norm2.scale = assign_check(gpt.trf_blocks[b].norm2.scale, d[f\"h.{b}.ln_2.weight\"])\n",
|
||||
" gpt.trf_blocks[b].norm2.shift = assign_check(gpt.trf_blocks[b].norm2.shift, d[f\"h.{b}.ln_2.bias\"])\n",
|
||||
" \n",
|
||||
" gpt.final_norm.scale = assign_check(gpt.final_norm.scale, d[f\"ln_f.weight\"])\n",
|
||||
" gpt.final_norm.shift = assign_check(gpt.final_norm.shift, d[f\"ln_f.bias\"])\n",
|
||||
" gpt.out_head.weight = assign_check(gpt.out_head.weight, d[\"wte.weight\"])"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": 7,
|
||||
"id": "cda44d37-92c0-4c19-a70a-15711513afce",
|
||||
"metadata": {},
|
||||
"outputs": [
|
||||
{
|
||||
"name": "stderr",
|
||||
"output_type": "stream",
|
||||
"text": [
|
||||
"/var/folders/jg/tpqyh1fd5js5wsr1d138k3n40000gn/T/ipykernel_32618/3877979348.py:4: UserWarning: To copy construct from a tensor, it is recommended to use sourceTensor.clone().detach() or sourceTensor.clone().detach().requires_grad_(True), rather than torch.tensor(sourceTensor).\n",
|
||||
" return torch.nn.Parameter(torch.tensor(right))\n"
|
||||
]
|
||||
}
|
||||
],
|
||||
"source": [
|
||||
"import torch\n",
|
||||
"from previous_chapters import GPTModel\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"gpt = GPTModel(BASE_CONFIG)\n",
|
||||
"\n",
|
||||
"device = torch.device(\"cuda\" if torch.cuda.is_available() else \"cpu\")\n",
|
||||
"load_weights(gpt, gpt_hf)\n",
|
||||
"gpt.to(device);"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": 8,
|
||||
"id": "4ddd0d51-3ade-4890-9bab-d63f141d095f",
|
||||
"metadata": {},
|
||||
"outputs": [
|
||||
{
|
||||
"name": "stdout",
|
||||
"output_type": "stream",
|
||||
"text": [
|
||||
"Output text:\n",
|
||||
" Every effort moves forward, but it's not enough.\n",
|
||||
"\n",
|
||||
"\"I'm not going to sit here and say, 'I'm not going to do this,'\n"
|
||||
]
|
||||
}
|
||||
],
|
||||
"source": [
|
||||
"import tiktoken\n",
|
||||
"from previous_chapters import generate, text_to_token_ids, token_ids_to_text\n",
|
||||
"\n",
|
||||
"torch.manual_seed(123)\n",
|
||||
"\n",
|
||||
"tokenizer = tiktoken.get_encoding(\"gpt2\")\n",
|
||||
"\n",
|
||||
"token_ids = generate(\n",
|
||||
" model=gpt,\n",
|
||||
" idx=text_to_token_ids(\"Every effort moves\", tokenizer),\n",
|
||||
" max_new_tokens=30,\n",
|
||||
" context_size=BASE_CONFIG[\"ctx_len\"],\n",
|
||||
" top_k=1,\n",
|
||||
" temperature=1.0\n",
|
||||
")\n",
|
||||
"\n",
|
||||
"print(\"Output text:\\n\", token_ids_to_text(token_ids, tokenizer))"
|
||||
]
|
||||
}
|
||||
],
|
||||
"metadata": {
|
||||
"kernelspec": {
|
||||
"display_name": "Python 3 (ipykernel)",
|
||||
"language": "python",
|
||||
"name": "python3"
|
||||
},
|
||||
"language_info": {
|
||||
"codemirror_mode": {
|
||||
"name": "ipython",
|
||||
"version": 3
|
||||
},
|
||||
"file_extension": ".py",
|
||||
"mimetype": "text/x-python",
|
||||
"name": "python",
|
||||
"nbconvert_exporter": "python",
|
||||
"pygments_lexer": "ipython3",
|
||||
"version": "3.11.4"
|
||||
}
|
||||
},
|
||||
"nbformat": 4,
|
||||
"nbformat_minor": 5
|
||||
}
|
||||
@@ -0,0 +1,122 @@
|
||||
# Pretraining GPT on the Project Gutenberg Dataset
|
||||
|
||||
The code in this directory contains code for training a small GPT model on the free books provided by Project Gutenberg.
|
||||
|
||||
As the Project Gutenberg website states, "the vast majority of Project Gutenberg eBooks are in the public domain in the US."
|
||||
|
||||
Please read the [Project Gutenberg Permissions, Licensing and other Common Requests](https://www.gutenberg.org/policy/permission.html) page for more information about using the resources provided by Project Gutenberg.
|
||||
|
||||
|
||||
## How to use this code
|
||||
|
||||
|
||||
|
||||
### 1) Download the dataset
|
||||
|
||||
As of this writing, this will require approximately 50 GB of disk space, but it may be more depending on how much Project Gutenberg grew since then.
|
||||
|
||||
Follow these steps to download the dataset:
|
||||
|
||||
|
||||
1. `git clone https://github.com/pgcorpus/gutenberg.git`
|
||||
|
||||
2. `cd gutenberg`
|
||||
|
||||
3. `pip install -r requirements.txt`
|
||||
|
||||
4. `python get_data.py`
|
||||
|
||||
5. `cd ..`
|
||||
|
||||
|
||||
### 2) Prepare the dataset
|
||||
|
||||
Next, run the `prepare_dataset.py` script, which concatenates the (as of this writing, 60,173) text files into fewer larger files so that they can be more efficiently transferred and accessed:
|
||||
|
||||
```
|
||||
prepare_dataset.py \
|
||||
--data_dir "gutenberg/data" \
|
||||
--max_size_mb 500 \
|
||||
--output_dir "gutenberg_preprocessed"
|
||||
```
|
||||
|
||||
> [!TIP]
|
||||
> Note that the produced files are stored in plaintext format and are not pre-tokenized for simplicity. However, you may want to update the codes to store the dataset in a pre-tokenized form to save computation time if you are planning to use the dataset more often or train for multiple epochs. See the *Design Decisions and Improvements* at the bottom of this page for more information.
|
||||
|
||||
> [!TIP]
|
||||
> You can choose smaller file sizes, for example, 50 MB. This will result in more files but might be useful for quicker pretraining runs on a small number of files for testing purposes.
|
||||
|
||||
|
||||
|
||||
### 3) Run the pretraining script
|
||||
|
||||
You can run the pretraining script as follows. Note that the additional command line arguments are shown with the default values for illustration purposes:
|
||||
|
||||
```bash
|
||||
pretraining_simple.py \
|
||||
--data_dir "gutenberg_preprocessed" \
|
||||
--n_epochs 1 \
|
||||
--batch_size 4 \
|
||||
--output_dir model_checkpoints
|
||||
```
|
||||
|
||||
The output will be formatted in the following way:
|
||||
|
||||
```
|
||||
Total files: 3
|
||||
Tokenizing file 1 of 3: data_small/combined_1.txt
|
||||
Training ...
|
||||
Ep 1 (Step 0): Train loss 9.694, Val loss 9.724
|
||||
Ep 1 (Step 100): Train loss 6.672, Val loss 6.683
|
||||
Ep 1 (Step 200): Train loss 6.543, Val loss 6.434
|
||||
Ep 1 (Step 300): Train loss 5.772, Val loss 6.313
|
||||
Ep 1 (Step 400): Train loss 5.547, Val loss 6.249
|
||||
Ep 1 (Step 500): Train loss 6.182, Val loss 6.155
|
||||
Ep 1 (Step 600): Train loss 5.742, Val loss 6.122
|
||||
Ep 1 (Step 700): Train loss 6.309, Val loss 5.984
|
||||
Ep 1 (Step 800): Train loss 5.435, Val loss 5.975
|
||||
Ep 1 (Step 900): Train loss 5.582, Val loss 5.935
|
||||
...
|
||||
Ep 1 (Step 31900): Train loss 3.664, Val loss 3.946
|
||||
Ep 1 (Step 32000): Train loss 3.493, Val loss 3.939
|
||||
Ep 1 (Step 32100): Train loss 3.940, Val loss 3.961
|
||||
Saved model_checkpoints/model_pg_32188.pth
|
||||
Book processed 3h 46m 55s
|
||||
Total time elapsed 3h 46m 55s
|
||||
ETA for remaining books: 7h 33m 50s
|
||||
Tokenizing file 2 of 3: data_small/combined_2.txt
|
||||
Training ...
|
||||
Ep 1 (Step 32200): Train loss 2.982, Val loss 4.094
|
||||
Ep 1 (Step 32300): Train loss 3.920, Val loss 4.097
|
||||
...
|
||||
```
|
||||
|
||||
|
||||
|
||||
> [!TIP]
|
||||
> In practice, if you are using macOS or Linux, I recommend using the `tee` command to save the log outputs to a `log.txt` file in addition to printing them on the terminal:
|
||||
|
||||
```bash
|
||||
python -u pretraining_simple.py | tee log.txt
|
||||
```
|
||||
|
||||
|
||||
> [!WARNING]
|
||||
> Note that training on 1 of the ~500 Mb text files in the `gutenberg_preprocessed` folder will take approximately 4 hours on a V100 GPU.
|
||||
> The folder contains 47 files and will take approximately 200 hours (more than 1 week) to complete. You may want to run it on a smaller number of files.
|
||||
|
||||
|
||||
|
||||
## Design Decisions and Improvements
|
||||
|
||||
Note that this code focuses on keeping things simple and minimal for educational purposes. The code could be improved in the following ways to improve modeling performance and training efficiency:
|
||||
|
||||
1. Modify the `prepare_dataset.py` script to strip the Gutenberg boilerplate text from each book file.
|
||||
2. Update the data preparation and loading utilities to pre-tokenize the dataset and save it in a tokenized form so that it doesn't have to be re-tokenized each time when calling the pretraining script.
|
||||
3. Update the `train_model_simple` script by adding the features introduced in [Appendix D: Adding Bells and Whistles to the Training Loop](../../appendix-D/01_main-chapter-code/appendix-D.ipynb), namely, cosine decay, linear warmup, and gradient clipping.
|
||||
4. Update the pretraining script to save the optimizer state (see section *5.4 Loading and saving weights in PyTorch* in chapter 5; [ch05.ipynb](../../ch05/01_main-chapter-code/ch05.ipynb)) and add the option to load an existing model and optimizer checkpoint and continue training if the training run was interrupted.
|
||||
5. Add a more advanced logger (for example, Weights and Biases) to view the loss and validation curves live
|
||||
6. Add distributed data parallelism (DDP) and train the model on multiple GPUs (see section *A.9.3 Training with multiple GPUs* in appendix A; [DDP-script.py](../../appendix-A/03_main-chapter-code/DDP-script.py)).
|
||||
7. Swap the from scratch `MultiheadAttention` class in the `previous_chapter.py` script with the efficient `MHAPyTorchScaledDotProduct` class implemented in the [Efficient Multi-Head Attention Implementations](../../ch03/02_bonus_efficient-multihead-attention/mha-implementations.ipynb) bonus section, which uses Flash Attention via PyTorch's `nn.functional.scaled_dot_product_attention` function.
|
||||
8. Speeding up the training by optimizing the model via [torch.compile](https://pytorch.org/tutorials/intermediate/torch_compile_tutorial.html) (`model = torch.compile`) or [thunder](https://github.com/Lightning-AI/lightning-thunder) (`model = thunder.jit(model)`).
|
||||
9. Implement Gradient Low-Rank Projection (GaLore) to further speed up the pretraining process. This can be achieved by just replacing the `AdamW` optimizer with the provided `GaLoreAdamW` provided in the [GaLore Python library](https://github.com/jiaweizzhao/GaLore).
|
||||
@@ -0,0 +1,70 @@
|
||||
# Copyright (c) Sebastian Raschka under Apache License 2.0 (see LICENSE.txt).
|
||||
# Source for "Build a Large Language Model From Scratch"
|
||||
# - https://www.manning.com/books/build-a-large-language-model-from-scratch
|
||||
# Code: https://github.com/rasbt/LLMs-from-scratch
|
||||
|
||||
"""
|
||||
Script that processes the Project Gutenberg files into fewer larger files.
|
||||
"""
|
||||
|
||||
import argparse
|
||||
import os
|
||||
|
||||
|
||||
def combine_files(file_paths, target_dir, max_size_mb=500, separator="<|endoftext|>", fallback_encoding="latin1"):
|
||||
if not os.path.exists(target_dir):
|
||||
os.makedirs(target_dir)
|
||||
|
||||
current_content = []
|
||||
current_size = 0
|
||||
file_counter = 1
|
||||
|
||||
for file_path in file_paths:
|
||||
try:
|
||||
with open(file_path, "r", encoding="utf-8") as file:
|
||||
content = file.read()
|
||||
except UnicodeDecodeError:
|
||||
# Attempt to read the file with a fallback encoding
|
||||
print(f"Warning: UnicodeDecodeError encountered. Trying fallback encoding for {file_path}")
|
||||
with open(file_path, "r", encoding=fallback_encoding) as file:
|
||||
content = file.read()
|
||||
|
||||
estimated_size = len(content.encode("utf-8"))
|
||||
|
||||
if current_size + estimated_size > max_size_mb * 1024 * 1024:
|
||||
target_file_path = os.path.join(target_dir, f"combined_{file_counter}.txt")
|
||||
with open(target_file_path, "w", encoding="utf-8") as target_file:
|
||||
target_file.write(separator.join(current_content))
|
||||
file_counter += 1
|
||||
current_content = [content]
|
||||
current_size = estimated_size
|
||||
else:
|
||||
current_content.append(content)
|
||||
current_size += estimated_size
|
||||
|
||||
if current_content:
|
||||
target_file_path = os.path.join(target_dir, f"combined_{file_counter}.txt")
|
||||
with open(target_file_path, "w", encoding="utf-8") as target_file:
|
||||
target_file.write(separator.join(current_content))
|
||||
|
||||
|
||||
if __name__ == "__main__":
|
||||
|
||||
parser = argparse.ArgumentParser(description="GPT Model Training Configuration")
|
||||
|
||||
parser.add_argument("--data_dir", type=str, default="gutenberg/data",
|
||||
help="Directory containing the downloaded raw training data")
|
||||
parser.add_argument("--max_size_mb", type=int, default=500,
|
||||
help="The maximum file size for each concatenated file in megabytes")
|
||||
parser.add_argument("--output_dir", type=str, default="gutenberg_preprocessed",
|
||||
help="Directory where the preprocessed data will be saved")
|
||||
|
||||
args = parser.parse_args()
|
||||
|
||||
all_files = [os.path.join(path, name) for path, subdirs, files in os.walk(args.data_dir)
|
||||
for name in files if name.endswith((".txt", ".txt.utf8")) and "raw" not in path]
|
||||
|
||||
target_dir = "path_to_your_large_files"
|
||||
print(f"{len(all_files)} files to process.")
|
||||
|
||||
combine_files(all_files, args.output_dir)
|
||||
@@ -0,0 +1,218 @@
|
||||
# Copyright (c) Sebastian Raschka under Apache License 2.0 (see LICENSE.txt).
|
||||
# Source for "Build a Large Language Model From Scratch"
|
||||
# - https://www.manning.com/books/build-a-large-language-model-from-scratch
|
||||
# Code: https://github.com/rasbt/LLMs-from-scratch
|
||||
|
||||
"""
|
||||
Script for pretraining a small GPT-2 124M parameter model
|
||||
on books from Project Gutenberg.
|
||||
|
||||
Before running this script, make sure you downloaded and
|
||||
processed the dataset as described in the README.md.
|
||||
"""
|
||||
|
||||
import argparse
|
||||
import os
|
||||
from pathlib import Path
|
||||
import time
|
||||
import torch
|
||||
from previous_chapters import (
|
||||
create_dataloader_v1,
|
||||
GPTModel,
|
||||
generate_and_print_sample,
|
||||
calc_loss_batch,
|
||||
evaluate_model,
|
||||
plot_losses
|
||||
)
|
||||
|
||||
|
||||
def read_text_file(file_path):
|
||||
with open(file_path, "r", encoding="utf-8") as file:
|
||||
text_data = file.read()
|
||||
return text_data
|
||||
|
||||
|
||||
def create_dataloaders(text_data, train_ratio, batch_size, max_length, stride):
|
||||
split_idx = int(train_ratio * len(text_data))
|
||||
train_loader = create_dataloader_v1(
|
||||
text_data[:split_idx],
|
||||
batch_size=batch_size,
|
||||
max_length=max_length,
|
||||
stride=stride,
|
||||
drop_last=True,
|
||||
shuffle=True
|
||||
)
|
||||
val_loader = create_dataloader_v1(
|
||||
text_data[split_idx:],
|
||||
batch_size=batch_size,
|
||||
max_length=max_length,
|
||||
stride=stride,
|
||||
drop_last=False,
|
||||
shuffle=False
|
||||
)
|
||||
return train_loader, val_loader
|
||||
|
||||
|
||||
def convert_time(seconds):
|
||||
hours, rem = divmod(seconds, 3600)
|
||||
minutes, seconds = divmod(rem, 60)
|
||||
return int(hours), int(minutes), int(seconds)
|
||||
|
||||
|
||||
def print_eta(start_time, book_start_time, index, total_files):
|
||||
book_end_time = time.time() # End time of processing this book
|
||||
elapsed_time = book_end_time - book_start_time
|
||||
total_elapsed_time = book_end_time - start_time
|
||||
books_remaining = total_files - index
|
||||
average_time_per_book = total_elapsed_time / index
|
||||
eta = average_time_per_book * books_remaining
|
||||
|
||||
book_h, book_m, book_s = convert_time(elapsed_time)
|
||||
total_h, total_m, total_s = convert_time(total_elapsed_time)
|
||||
eta_h, eta_m, eta_s = convert_time(eta)
|
||||
|
||||
print(f"Book processed {book_h}h {book_m}m {book_s}s"
|
||||
f"\nTotal time elapsed {total_h}h {total_m}m {total_s}s"
|
||||
f"\nETA for remaining books: {eta_h}h {eta_m}m {eta_s}s")
|
||||
|
||||
|
||||
def train_model_simple(model, optimizer, device, n_epochs,
|
||||
eval_freq, eval_iter, print_sample_iter, start_context,
|
||||
output_dir, save_ckpt_freq,
|
||||
batch_size=1024, train_ratio=0.90):
|
||||
|
||||
train_losses, val_losses, track_tokens_seen = [], [], []
|
||||
tokens_seen = 0
|
||||
global_step = -1
|
||||
start_time = time.time()
|
||||
|
||||
try:
|
||||
for epoch in range(n_epochs):
|
||||
|
||||
# Iterate over the books in the training corpus
|
||||
for index, file_path in enumerate(all_files, 1):
|
||||
book_start_time = time.time()
|
||||
text_data = read_text_file(file_path) + " <|endoftext|> "
|
||||
print(f"Tokenizing file {index} of {total_files}: {file_path}")
|
||||
|
||||
# Initialize new data loaders for each book
|
||||
train_loader, val_loader = create_dataloaders(
|
||||
text_data,
|
||||
train_ratio=train_ratio,
|
||||
batch_size=batch_size,
|
||||
max_length=GPT_CONFIG_124M["ctx_len"],
|
||||
stride=GPT_CONFIG_124M["ctx_len"]
|
||||
)
|
||||
print("Training ...")
|
||||
model.train()
|
||||
for input_batch, target_batch in train_loader:
|
||||
optimizer.zero_grad()
|
||||
loss = calc_loss_batch(input_batch, target_batch, model, device)
|
||||
loss.backward()
|
||||
optimizer.step()
|
||||
tokens_seen += input_batch.numel()
|
||||
global_step += 1
|
||||
|
||||
# Optional evaluation step
|
||||
if global_step % eval_freq == 0:
|
||||
train_loss, val_loss = evaluate_model(
|
||||
model, train_loader, val_loader, device, eval_iter)
|
||||
train_losses.append(train_loss)
|
||||
val_losses.append(val_loss)
|
||||
track_tokens_seen.append(tokens_seen)
|
||||
print(f"Ep {epoch+1} (Step {global_step}): "
|
||||
f"Train loss {train_loss:.3f}, Val loss {val_loss:.3f}")
|
||||
|
||||
# Generate text passage
|
||||
if global_step % print_sample_iter == 0:
|
||||
generate_and_print_sample(
|
||||
model, train_loader.dataset.tokenizer, device, start_context
|
||||
)
|
||||
|
||||
if global_step % save_ckpt_freq:
|
||||
file_name = output_dir / f"model_pg_{global_step}.pth"
|
||||
torch.save(model.state_dict(), file_name)
|
||||
print(f"Saved {file_name}")
|
||||
|
||||
print_eta(start_time, book_start_time, index, total_files)
|
||||
|
||||
except KeyboardInterrupt:
|
||||
file_name = output_dir / f"model_pg_{global_step}_interrupted.pth"
|
||||
torch.save(model.state_dict(), file_name)
|
||||
print(f"Saved {file_name}")
|
||||
|
||||
return train_losses, val_losses, track_tokens_seen
|
||||
|
||||
|
||||
if __name__ == "__main__":
|
||||
|
||||
parser = argparse.ArgumentParser(description='GPT Model Training Configuration')
|
||||
|
||||
parser.add_argument('--data_dir', type=str, default='gutenberg/data',
|
||||
help='Directory containing the training data')
|
||||
parser.add_argument('--output_dir', type=str, default='model_checkpoints',
|
||||
help='Directory where the model checkpoints will be saved')
|
||||
parser.add_argument('--n_epochs', type=int, default=1,
|
||||
help='Number of epochs to train the model')
|
||||
parser.add_argument('--print_sample_iter', type=int, default=1000,
|
||||
help='Iterations between printing sample outputs')
|
||||
parser.add_argument('--eval_freq', type=int, default=100,
|
||||
help='Frequency of evaluations during training')
|
||||
parser.add_argument('--save_ckpt_freq', type=int, default=100_000,
|
||||
help='Frequency of saving model checkpoints during training')
|
||||
parser.add_argument('--lr', type=float, default=5e-4,
|
||||
help='Learning rate for the optimizer')
|
||||
parser.add_argument('--batch_size', type=int, default=4,
|
||||
help='Batch size for training')
|
||||
|
||||
args = parser.parse_args()
|
||||
|
||||
GPT_CONFIG_124M = {
|
||||
"vocab_size": 50257, # Vocabulary size
|
||||
"ctx_len": 1024, # Context length
|
||||
"emb_dim": 768, # Embedding dimension
|
||||
"n_heads": 12, # Number of attention heads
|
||||
"n_layers": 12, # Number of layers
|
||||
"drop_rate": 0.1, # Dropout rate
|
||||
"qkv_bias": False # Query-key-value bias
|
||||
}
|
||||
|
||||
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
|
||||
torch.manual_seed(123)
|
||||
model = GPTModel(GPT_CONFIG_124M)
|
||||
model.to(device)
|
||||
optimizer = torch.optim.AdamW(model.parameters(), lr=args.lr, weight_decay=0.1)
|
||||
|
||||
data_dir = args.data_dir
|
||||
all_files = [os.path.join(path, name) for path, subdirs, files
|
||||
in os.walk(data_dir) for name in files if name.endswith((".txt"))]
|
||||
total_files = len(all_files)
|
||||
|
||||
if total_files == 0:
|
||||
print("No training text files found. Make sure you "
|
||||
"selected the correct input directory")
|
||||
quit()
|
||||
print("Total files:", total_files)
|
||||
|
||||
output_dir = Path(args.output_dir)
|
||||
output_dir.mkdir(parents=True, exist_ok=True)
|
||||
|
||||
train_losses, val_losses, tokens_seen = train_model_simple(
|
||||
model, optimizer, device,
|
||||
batch_size=args.batch_size,
|
||||
n_epochs=args.n_epochs,
|
||||
eval_freq=args.eval_freq,
|
||||
eval_iter=1,
|
||||
print_sample_iter=args.print_sample_iter,
|
||||
output_dir=output_dir,
|
||||
save_ckpt_freq=args.save_ckpt_freq,
|
||||
start_context="Every effort moves you",
|
||||
)
|
||||
|
||||
epochs_tensor = torch.linspace(0, args.n_epochs, len(train_losses))
|
||||
|
||||
print("debug", epochs_tensor, tokens_seen, train_losses, val_losses, output_dir)
|
||||
plot_losses(epochs_tensor, tokens_seen, train_losses, val_losses, output_dir)
|
||||
|
||||
torch.save(model.state_dict(), output_dir / "model_pg_final.pth")
|
||||
print(f"Maximum GPU memory allocated: {torch.cuda.max_memory_allocated() / 1e9:.2f} GB")
|
||||
@@ -0,0 +1,316 @@
|
||||
# Copyright (c) Sebastian Raschka under Apache License 2.0 (see LICENSE.txt).
|
||||
# Source for "Build a Large Language Model From Scratch"
|
||||
# - https://www.manning.com/books/build-a-large-language-model-from-scratch
|
||||
# Code: https://github.com/rasbt/LLMs-from-scratch
|
||||
|
||||
# This file collects all the relevant code that we covered thus far
|
||||
# throughout Chapters 2-4.
|
||||
# This file can be run as a standalone script.
|
||||
|
||||
import tiktoken
|
||||
import torch
|
||||
import torch.nn as nn
|
||||
from torch.utils.data import Dataset, DataLoader
|
||||
import matplotlib.pyplot as plt
|
||||
|
||||
|
||||
#####################################
|
||||
# Chapter 2
|
||||
#####################################
|
||||
|
||||
|
||||
class GPTDatasetV1(Dataset):
|
||||
def __init__(self, txt, tokenizer, max_length, stride):
|
||||
self.tokenizer = tokenizer
|
||||
self.input_ids = []
|
||||
self.target_ids = []
|
||||
|
||||
token_ids = tokenizer.encode(txt, allowed_special={'<|endoftext|>'})
|
||||
|
||||
for i in range(0, len(token_ids) - max_length, stride):
|
||||
input_chunk = token_ids[i:i + max_length]
|
||||
target_chunk = token_ids[i + 1: i + max_length + 1]
|
||||
self.input_ids.append(torch.tensor(input_chunk))
|
||||
self.target_ids.append(torch.tensor(target_chunk))
|
||||
|
||||
def __len__(self):
|
||||
return len(self.input_ids)
|
||||
|
||||
def __getitem__(self, idx):
|
||||
return self.input_ids[idx], self.target_ids[idx]
|
||||
|
||||
|
||||
def create_dataloader_v1(txt, batch_size=4, max_length=256,
|
||||
stride=128, shuffle=True, drop_last=True):
|
||||
tokenizer = tiktoken.get_encoding("gpt2")
|
||||
dataset = GPTDatasetV1(txt, tokenizer, max_length, stride)
|
||||
dataloader = DataLoader(
|
||||
dataset, batch_size=batch_size, shuffle=shuffle, drop_last=drop_last)
|
||||
|
||||
return dataloader
|
||||
|
||||
|
||||
#####################################
|
||||
# Chapter 3
|
||||
#####################################
|
||||
|
||||
class MultiHeadAttention(nn.Module):
|
||||
def __init__(self, d_in, d_out, block_size, dropout, num_heads, qkv_bias=False):
|
||||
super().__init__()
|
||||
assert d_out % num_heads == 0, "d_out must be divisible by n_heads"
|
||||
|
||||
self.d_out = d_out
|
||||
self.num_heads = num_heads
|
||||
self.head_dim = d_out // num_heads # Reduce the projection dim to match desired output dim
|
||||
|
||||
self.W_query = nn.Linear(d_in, d_out, bias=qkv_bias)
|
||||
self.W_key = nn.Linear(d_in, d_out, bias=qkv_bias)
|
||||
self.W_value = nn.Linear(d_in, d_out, bias=qkv_bias)
|
||||
self.out_proj = nn.Linear(d_out, d_out) # Linear layer to combine head outputs
|
||||
self.dropout = nn.Dropout(dropout)
|
||||
self.register_buffer('mask', torch.triu(torch.ones(block_size, block_size), diagonal=1))
|
||||
|
||||
def forward(self, x):
|
||||
b, num_tokens, d_in = x.shape
|
||||
|
||||
keys = self.W_key(x) # Shape: (b, num_tokens, d_out)
|
||||
queries = self.W_query(x)
|
||||
values = self.W_value(x)
|
||||
|
||||
# We implicitly split the matrix by adding a `num_heads` dimension
|
||||
# Unroll last dim: (b, num_tokens, d_out) -> (b, num_tokens, num_heads, head_dim)
|
||||
keys = keys.view(b, num_tokens, self.num_heads, self.head_dim)
|
||||
values = values.view(b, num_tokens, self.num_heads, self.head_dim)
|
||||
queries = queries.view(b, num_tokens, self.num_heads, self.head_dim)
|
||||
|
||||
# Transpose: (b, num_tokens, num_heads, head_dim) -> (b, num_heads, num_tokens, head_dim)
|
||||
keys = keys.transpose(1, 2)
|
||||
queries = queries.transpose(1, 2)
|
||||
values = values.transpose(1, 2)
|
||||
|
||||
# Compute scaled dot-product attention (aka self-attention) with a causal mask
|
||||
attn_scores = queries @ keys.transpose(2, 3) # Dot product for each head
|
||||
|
||||
# Original mask truncated to the number of tokens and converted to boolean
|
||||
mask_bool = self.mask.bool()[:num_tokens, :num_tokens]
|
||||
|
||||
# Use the mask to fill attention scores
|
||||
attn_scores.masked_fill_(mask_bool, -torch.inf)
|
||||
|
||||
attn_weights = torch.softmax(attn_scores / keys.shape[-1]**0.5, dim=-1)
|
||||
attn_weights = self.dropout(attn_weights)
|
||||
|
||||
# Shape: (b, num_tokens, num_heads, head_dim)
|
||||
context_vec = (attn_weights @ values).transpose(1, 2)
|
||||
|
||||
# Combine heads, where self.d_out = self.num_heads * self.head_dim
|
||||
context_vec = context_vec.reshape(b, num_tokens, self.d_out)
|
||||
context_vec = self.out_proj(context_vec) # optional projection
|
||||
|
||||
return context_vec
|
||||
|
||||
|
||||
#####################################
|
||||
# Chapter 4
|
||||
#####################################
|
||||
|
||||
class LayerNorm(nn.Module):
|
||||
def __init__(self, emb_dim):
|
||||
super().__init__()
|
||||
self.eps = 1e-5
|
||||
self.scale = nn.Parameter(torch.ones(emb_dim))
|
||||
self.shift = nn.Parameter(torch.zeros(emb_dim))
|
||||
|
||||
def forward(self, x):
|
||||
mean = x.mean(dim=-1, keepdim=True)
|
||||
var = x.var(dim=-1, keepdim=True, unbiased=False)
|
||||
norm_x = (x - mean) / torch.sqrt(var + self.eps)
|
||||
return self.scale * norm_x + self.shift
|
||||
|
||||
|
||||
class GELU(nn.Module):
|
||||
def __init__(self):
|
||||
super().__init__()
|
||||
|
||||
def forward(self, x):
|
||||
return 0.5 * x * (1 + torch.tanh(
|
||||
torch.sqrt(torch.tensor(2.0 / torch.pi)) *
|
||||
(x + 0.044715 * torch.pow(x, 3))
|
||||
))
|
||||
|
||||
|
||||
class FeedForward(nn.Module):
|
||||
def __init__(self, cfg):
|
||||
super().__init__()
|
||||
self.layers = nn.Sequential(
|
||||
nn.Linear(cfg["emb_dim"], 4 * cfg["emb_dim"]),
|
||||
GELU(),
|
||||
nn.Linear(4 * cfg["emb_dim"], cfg["emb_dim"]),
|
||||
nn.Dropout(cfg["drop_rate"])
|
||||
)
|
||||
|
||||
def forward(self, x):
|
||||
return self.layers(x)
|
||||
|
||||
|
||||
class TransformerBlock(nn.Module):
|
||||
def __init__(self, cfg):
|
||||
super().__init__()
|
||||
self.att = MultiHeadAttention(
|
||||
d_in=cfg["emb_dim"],
|
||||
d_out=cfg["emb_dim"],
|
||||
block_size=cfg["ctx_len"],
|
||||
num_heads=cfg["n_heads"],
|
||||
dropout=cfg["drop_rate"],
|
||||
qkv_bias=cfg["qkv_bias"])
|
||||
self.ff = FeedForward(cfg)
|
||||
self.norm1 = LayerNorm(cfg["emb_dim"])
|
||||
self.norm2 = LayerNorm(cfg["emb_dim"])
|
||||
self.drop_resid = nn.Dropout(cfg["drop_rate"])
|
||||
|
||||
def forward(self, x):
|
||||
# Shortcut connection for attention block
|
||||
shortcut = x
|
||||
x = self.norm1(x)
|
||||
x = self.att(x) # Shape [batch_size, num_tokens, emb_size]
|
||||
x = self.drop_resid(x)
|
||||
x = x + shortcut # Add the original input back
|
||||
|
||||
# Shortcut connection for feed-forward block
|
||||
shortcut = x
|
||||
x = self.norm2(x)
|
||||
x = self.ff(x)
|
||||
x = self.drop_resid(x)
|
||||
x = x + shortcut # Add the original input back
|
||||
|
||||
return x
|
||||
|
||||
|
||||
class GPTModel(nn.Module):
|
||||
def __init__(self, cfg):
|
||||
super().__init__()
|
||||
self.tok_emb = nn.Embedding(cfg["vocab_size"], cfg["emb_dim"])
|
||||
self.pos_emb = nn.Embedding(cfg["ctx_len"], cfg["emb_dim"])
|
||||
self.drop_emb = nn.Dropout(cfg["drop_rate"])
|
||||
|
||||
self.trf_blocks = nn.Sequential(
|
||||
*[TransformerBlock(cfg) for _ in range(cfg["n_layers"])])
|
||||
|
||||
self.final_norm = LayerNorm(cfg["emb_dim"])
|
||||
self.out_head = nn.Linear(cfg["emb_dim"], cfg["vocab_size"], bias=False)
|
||||
|
||||
def forward(self, in_idx):
|
||||
batch_size, seq_len = in_idx.shape
|
||||
tok_embeds = self.tok_emb(in_idx)
|
||||
pos_embeds = self.pos_emb(torch.arange(seq_len, device=in_idx.device))
|
||||
x = tok_embeds + pos_embeds # Shape [batch_size, num_tokens, emb_size]
|
||||
x = self.drop_emb(x)
|
||||
x = self.trf_blocks(x)
|
||||
x = self.final_norm(x)
|
||||
logits = self.out_head(x)
|
||||
return logits
|
||||
|
||||
|
||||
def generate_text_simple(model, idx, max_new_tokens, context_size):
|
||||
# idx is (B, T) array of indices in the current context
|
||||
for _ in range(max_new_tokens):
|
||||
|
||||
# Crop current context if it exceeds the supported context size
|
||||
# E.g., if LLM supports only 5 tokens, and the context size is 10
|
||||
# then only the last 5 tokens are used as context
|
||||
idx_cond = idx[:, -context_size:]
|
||||
|
||||
# Get the predictions
|
||||
with torch.no_grad():
|
||||
logits = model(idx_cond)
|
||||
|
||||
# Focus only on the last time step
|
||||
# (batch, n_token, vocab_size) becomes (batch, vocab_size)
|
||||
logits = logits[:, -1, :]
|
||||
|
||||
# Get the idx of the vocab entry with the highest logits value
|
||||
idx_next = torch.argmax(logits, dim=-1, keepdim=True) # (batch, 1)
|
||||
|
||||
# Append sampled index to the running sequence
|
||||
idx = torch.cat((idx, idx_next), dim=1) # (batch, n_tokens+1)
|
||||
|
||||
return idx
|
||||
|
||||
|
||||
#####################################
|
||||
# Chapter 5
|
||||
####################################
|
||||
|
||||
|
||||
def calc_loss_batch(input_batch, target_batch, model, device):
|
||||
input_batch, target_batch = input_batch.to(device), target_batch.to(device)
|
||||
logits = model(input_batch)
|
||||
loss = torch.nn.functional.cross_entropy(logits.flatten(0, -1), target_batch.flatten())
|
||||
return loss
|
||||
|
||||
|
||||
def calc_loss_loader(data_loader, model, device, num_batches=None):
|
||||
total_loss = 0.
|
||||
if num_batches is None:
|
||||
num_batches = len(data_loader)
|
||||
else:
|
||||
num_batches = min(num_batches, len(data_loader))
|
||||
for i, (input_batch, target_batch) in enumerate(data_loader):
|
||||
if i < num_batches:
|
||||
loss = calc_loss_batch(input_batch, target_batch, model, device)
|
||||
total_loss += loss.item()
|
||||
else:
|
||||
break
|
||||
return total_loss / num_batches
|
||||
|
||||
|
||||
def evaluate_model(model, train_loader, val_loader, device, eval_iter):
|
||||
model.eval()
|
||||
with torch.no_grad():
|
||||
train_loss = calc_loss_loader(train_loader, model, device, num_batches=eval_iter)
|
||||
val_loss = calc_loss_loader(val_loader, model, device, num_batches=eval_iter)
|
||||
model.train()
|
||||
return train_loss, val_loss
|
||||
|
||||
|
||||
def generate_and_print_sample(model, tokenizer, device, start_context):
|
||||
model.eval()
|
||||
context_size = model.pos_emb.weight.shape[0]
|
||||
encoded = text_to_token_ids(start_context, tokenizer).to(device)
|
||||
with torch.no_grad():
|
||||
token_ids = generate_text_simple(
|
||||
model=model, idx=encoded,
|
||||
max_new_tokens=50, context_size=context_size)
|
||||
decoded_text = token_ids_to_text(token_ids, tokenizer)
|
||||
print(decoded_text.replace("\n", " ")) # Compact print format
|
||||
model.train()
|
||||
|
||||
|
||||
def plot_losses(epochs_seen, tokens_seen, train_losses, val_losses, output_dir):
|
||||
fig, ax1 = plt.subplots()
|
||||
|
||||
# Plot training and validation loss against epochs
|
||||
ax1.plot(epochs_seen, train_losses, label="Training loss")
|
||||
ax1.plot(epochs_seen, val_losses, linestyle="-.", label="Validation loss")
|
||||
ax1.set_xlabel("Epochs")
|
||||
ax1.set_ylabel("Loss")
|
||||
ax1.legend(loc="upper right")
|
||||
|
||||
# Create a second x-axis for tokens seen
|
||||
ax2 = ax1.twiny() # Create a second x-axis that shares the same y-axis
|
||||
ax2.plot(tokens_seen, train_losses, alpha=0) # Invisible plot for aligning ticks
|
||||
ax2.set_xlabel("Tokens seen")
|
||||
|
||||
fig.tight_layout() # Adjust layout to make room
|
||||
plt.savefig(output_dir / "losses.pdf")
|
||||
|
||||
|
||||
def text_to_token_ids(text, tokenizer):
|
||||
encoded = tokenizer.encode(text, allowed_special={'<|endoftext|>'})
|
||||
encoded_tensor = torch.tensor(encoded).unsqueeze(0) # Add batch dimension
|
||||
return encoded_tensor
|
||||
|
||||
|
||||
def token_ids_to_text(token_ids, tokenizer):
|
||||
flat = token_ids.squeeze(0) # Remove batch dimension
|
||||
return tokenizer.decode(flat.tolist())
|
||||
@@ -0,0 +1,5 @@
|
||||
# Adding Bells and Whistles to the Training Loop
|
||||
|
||||
The main chapter used a relatively simple training function to keep the code readable and fit Chapter 5 within the page limits. Optionally, we can add a linear warm-up, a cosine decay schedule, and gradient clipping to improve the training stability and convergence.
|
||||
|
||||
You can find the code for this more sophisticated training function in [Appendix D: Adding Bells and Whistles to the Training Loop](../../appendix-D/01_main-chapter-code/appendix-D.ipynb).
|
||||
@@ -0,0 +1,10 @@
|
||||
# Optimizing Hyperparameters for Pretraining
|
||||
|
||||
The [hparam_search.py](hparam_search.py) is script based on the extended training function in [
|
||||
Appendix D: Adding Bells and Whistles to the Training Loop](../appendix-D/01_main-chapter-code/appendix-D.ipynb) to find optimal hyperparameters via grid search
|
||||
|
||||
The [hparam_search.py](hparam_search.py) script, based on the extended training function in [
|
||||
Appendix D: Adding Bells and Whistles to the Training Loop](../appendix-D/01_main-chapter-code/appendix-D.ipynb), is designed to find optimal hyperparameters via grid search.
|
||||
|
||||
>[!NOTE]
|
||||
This script will take a long time to run. You may want to reduce the number of hyperparameter configurations explored in the `HPARAM_GRID` dictionary at the top.
|
||||
@@ -0,0 +1,208 @@
|
||||
# Copyright (c) Sebastian Raschka under Apache License 2.0 (see LICENSE.txt).
|
||||
# Source for "Build a Large Language Model From Scratch"
|
||||
# - https://www.manning.com/books/build-a-large-language-model-from-scratch
|
||||
# Code: https://github.com/rasbt/LLMs-from-scratch
|
||||
|
||||
import itertools
|
||||
import math
|
||||
import os
|
||||
import torch
|
||||
from previous_chapters import GPTModel, create_dataloader_v1
|
||||
|
||||
|
||||
# Define a grid of hyperparameters to search over
|
||||
HPARAM_GRID = {
|
||||
"batch_size": [2, 4, 8, 16],
|
||||
"drop_rate": [0.0, 0.1, 0.2],
|
||||
"warmup_iters": [10, 20, 30],
|
||||
"weight_decay": [0.1, 0.01, 0.0],
|
||||
"peak_lr": [0.0001, 0.0005, 0.001, 0.005],
|
||||
"initial_lr": [0.00005, 0.0001],
|
||||
"min_lr": [0.00005, 0.00001, 0.0001],
|
||||
"n_epochs": [5, 10, 15, 20, 25],
|
||||
}
|
||||
|
||||
|
||||
def calc_loss_loader(data_loader, model, device, num_batches=None):
|
||||
total_loss = 0.
|
||||
if num_batches is None:
|
||||
num_batches = len(data_loader)
|
||||
else:
|
||||
num_batches = min(num_batches, len(data_loader))
|
||||
for i, (input_batch, target_batch) in enumerate(data_loader):
|
||||
if i < num_batches:
|
||||
loss = calc_loss_batch(input_batch, target_batch, model, device)
|
||||
total_loss += loss.item()
|
||||
else:
|
||||
break
|
||||
return total_loss / num_batches
|
||||
|
||||
|
||||
def calc_loss_batch(input_batch, target_batch, model, device):
|
||||
input_batch, target_batch = input_batch.to(device), target_batch.to(device)
|
||||
|
||||
logits = model(input_batch)
|
||||
logits = logits.view(-1, logits.size(-1))
|
||||
loss = torch.nn.functional.cross_entropy(logits, target_batch.view(-1))
|
||||
return loss
|
||||
|
||||
|
||||
def evaluate_model(model, train_loader, val_loader, device, eval_iter):
|
||||
model.eval()
|
||||
with torch.no_grad():
|
||||
train_loss = calc_loss_loader(train_loader, model, device, num_iters=eval_iter)
|
||||
val_loss = calc_loss_loader(val_loader, model, device, num_iters=eval_iter)
|
||||
model.train()
|
||||
return train_loss, val_loss
|
||||
|
||||
|
||||
def train_model(model, train_loader, val_loader, optimizer, device,
|
||||
n_epochs, eval_freq, eval_iter,
|
||||
encoded_start_context, warmup_iters=10,
|
||||
initial_lr=3e-05, min_lr=1e-6):
|
||||
global_step = 0
|
||||
|
||||
max_lr = optimizer.param_groups[0]["lr"]
|
||||
|
||||
# Calculate total number of iterations
|
||||
total_training_iters = len(train_loader) * n_epochs
|
||||
|
||||
# Calculate the learning rate increment at each step during warmup
|
||||
lr_increment = (optimizer.param_groups[0]["lr"] - initial_lr) / warmup_iters
|
||||
|
||||
for epoch in range(n_epochs):
|
||||
model.train()
|
||||
for input_batch, target_batch in train_loader:
|
||||
optimizer.zero_grad()
|
||||
|
||||
# Increment the global step at the beginning of the iteration
|
||||
global_step += 1
|
||||
|
||||
# Warmup: adjust learning rate linearly
|
||||
if global_step < warmup_iters:
|
||||
lr = initial_lr + global_step * lr_increment
|
||||
# Cosine annealing phase
|
||||
else:
|
||||
progress = (global_step - warmup_iters) / (total_training_iters - warmup_iters)
|
||||
lr = min_lr + (max_lr - min_lr) * 0.5 * (1 + math.cos(math.pi * progress))
|
||||
|
||||
# Apply the calculated learning rate
|
||||
for param_group in optimizer.param_groups:
|
||||
param_group["lr"] = lr
|
||||
|
||||
loss = calc_loss_batch(input_batch, target_batch, model, device)
|
||||
loss.backward()
|
||||
|
||||
# Apply gradient clipping
|
||||
if global_step >= warmup_iters:
|
||||
torch.nn.utils.clip_grad_norm_(model.parameters(), max_norm=1.0)
|
||||
|
||||
optimizer.step()
|
||||
|
||||
train_loss, val_loss = evaluate_model(model, train_loader, val_loader, device, eval_iter)
|
||||
|
||||
return train_loss, val_loss
|
||||
|
||||
|
||||
if __name__ == "__main__":
|
||||
|
||||
# Generate all combinations of hyperparameters
|
||||
hyperparameter_combinations = list(itertools.product(*HPARAM_GRID.values()))
|
||||
total_combinations = len(hyperparameter_combinations)
|
||||
print(f"Total hyperparameter configurations: {total_combinations}")
|
||||
|
||||
# Placeholder for the best loss and best hyperparameters
|
||||
best_val_loss = float('inf')
|
||||
best_hparams = {}
|
||||
|
||||
script_path = os.path.abspath(__file__)
|
||||
script_dir = os.path.dirname(script_path)
|
||||
with open(os.path.join(script_dir, "the-verdict.txt"), "r", encoding="utf-8") as file:
|
||||
text_data = file.read()
|
||||
|
||||
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
|
||||
|
||||
train_ratio = 0.95
|
||||
split_idx = int(train_ratio * len(text_data))
|
||||
|
||||
torch.manual_seed(123)
|
||||
|
||||
interrupted = False
|
||||
current_config = 0
|
||||
for combination in hyperparameter_combinations:
|
||||
|
||||
try:
|
||||
current_config += 1
|
||||
print(f"Evaluating configuration {current_config} of {total_combinations}")
|
||||
|
||||
# Unpack the current combination of hyperparameters
|
||||
HPARAM_CONFIG = dict(zip(HPARAM_GRID.keys(), combination))
|
||||
|
||||
GPT_CONFIG_124M = {
|
||||
"vocab_size": 50257, # Vocabulary size
|
||||
"ctx_len": 256, # Context length -- shortened from original 1024 tokens
|
||||
"emb_dim": 768, # Embedding dimension
|
||||
"n_heads": 12, # Number of attention heads
|
||||
"n_layers": 12, # Number of layers
|
||||
"drop_rate": HPARAM_CONFIG["drop_rate"],
|
||||
"qkv_bias": False, # Query-Key-Value bias
|
||||
}
|
||||
|
||||
torch.manual_seed(123)
|
||||
train_loader = create_dataloader_v1(
|
||||
text_data[:split_idx],
|
||||
batch_size=HPARAM_CONFIG["batch_size"],
|
||||
max_length=GPT_CONFIG_124M["ctx_len"],
|
||||
stride=GPT_CONFIG_124M["ctx_len"],
|
||||
drop_last=True,
|
||||
shuffle=True
|
||||
)
|
||||
|
||||
val_loader = create_dataloader_v1(
|
||||
text_data[split_idx:],
|
||||
batch_size=HPARAM_CONFIG["batch_size"],
|
||||
max_length=GPT_CONFIG_124M["ctx_len"],
|
||||
stride=GPT_CONFIG_124M["ctx_len"],
|
||||
drop_last=False,
|
||||
shuffle=False
|
||||
)
|
||||
|
||||
model = GPTModel(GPT_CONFIG_124M)
|
||||
model.to(device)
|
||||
|
||||
optimizer = torch.optim.AdamW(
|
||||
model.parameters(),
|
||||
lr=HPARAM_CONFIG["peak_lr"],
|
||||
weight_decay=HPARAM_CONFIG["weight_decay"]
|
||||
)
|
||||
|
||||
encoded_start_context = train_loader.dataset.tokenizer.encode("Nevertheless")
|
||||
encoded_tensor = torch.tensor(encoded_start_context).unsqueeze(0)
|
||||
|
||||
train_loss, val_loss = train_model(
|
||||
model, train_loader, val_loader, optimizer, device,
|
||||
n_epochs=HPARAM_CONFIG["n_epochs"],
|
||||
eval_freq=5, eval_iter=1,
|
||||
encoded_start_context=encoded_tensor,
|
||||
warmup_iters=HPARAM_CONFIG["warmup_iters"],
|
||||
initial_lr=HPARAM_CONFIG["initial_lr"],
|
||||
min_lr=HPARAM_CONFIG["min_lr"]
|
||||
)
|
||||
|
||||
# Log the best hyperparameters based on validation loss
|
||||
if val_loss < best_val_loss:
|
||||
best_val_loss = val_loss
|
||||
best_train_loss = train_loss
|
||||
best_hparams = HPARAM_CONFIG
|
||||
|
||||
except KeyboardInterrupt:
|
||||
print("Hyperparameter search completed.")
|
||||
print(f"Best hyperparameters: {best_hparams}")
|
||||
print(f"Best Val loss: {best_val_loss} | Training loss {train_loss}")
|
||||
interrupted = True
|
||||
break
|
||||
|
||||
if not interrupted:
|
||||
print("Hyperparameter search completed.")
|
||||
print(f"Best hyperparameters: {best_hparams}")
|
||||
print(f"Best Val loss: {best_val_loss} | Training loss {train_loss}")
|
||||
@@ -0,0 +1,281 @@
|
||||
# Copyright (c) Sebastian Raschka under Apache License 2.0 (see LICENSE.txt).
|
||||
# Source for "Build a Large Language Model From Scratch"
|
||||
# - https://www.manning.com/books/build-a-large-language-model-from-scratch
|
||||
# Code: https://github.com/rasbt/LLMs-from-scratch
|
||||
|
||||
# This file collects all the relevant code that we covered thus far
|
||||
# throughout Chapters 2-4.
|
||||
# This file can be run as a standalone script.
|
||||
|
||||
import tiktoken
|
||||
import torch
|
||||
import torch.nn as nn
|
||||
from torch.utils.data import Dataset, DataLoader
|
||||
|
||||
#####################################
|
||||
# Chapter 2
|
||||
#####################################
|
||||
|
||||
|
||||
class GPTDatasetV1(Dataset):
|
||||
def __init__(self, txt, tokenizer, max_length, stride):
|
||||
self.tokenizer = tokenizer
|
||||
self.input_ids = []
|
||||
self.target_ids = []
|
||||
|
||||
# Tokenize the entire text
|
||||
token_ids = tokenizer.encode(txt)
|
||||
|
||||
# Use a sliding window to chunk the book into overlapping sequences of max_length
|
||||
for i in range(0, len(token_ids) - max_length, stride):
|
||||
input_chunk = token_ids[i:i + max_length]
|
||||
target_chunk = token_ids[i + 1: i + max_length + 1]
|
||||
self.input_ids.append(torch.tensor(input_chunk))
|
||||
self.target_ids.append(torch.tensor(target_chunk))
|
||||
|
||||
def __len__(self):
|
||||
return len(self.input_ids)
|
||||
|
||||
def __getitem__(self, idx):
|
||||
return self.input_ids[idx], self.target_ids[idx]
|
||||
|
||||
|
||||
def create_dataloader_v1(txt, batch_size=4, max_length=256,
|
||||
stride=128, shuffle=True, drop_last=True):
|
||||
# Initialize the tokenizer
|
||||
tokenizer = tiktoken.get_encoding("gpt2")
|
||||
|
||||
# Create dataset
|
||||
dataset = GPTDatasetV1(txt, tokenizer, max_length, stride)
|
||||
|
||||
# Create dataloader
|
||||
dataloader = DataLoader(
|
||||
dataset, batch_size=batch_size, shuffle=shuffle, drop_last=drop_last)
|
||||
|
||||
return dataloader
|
||||
|
||||
|
||||
#####################################
|
||||
# Chapter 3
|
||||
#####################################
|
||||
class MultiHeadAttention(nn.Module):
|
||||
def __init__(self, d_in, d_out, block_size, dropout, num_heads, qkv_bias=False):
|
||||
super().__init__()
|
||||
assert d_out % num_heads == 0, "d_out must be divisible by num_heads"
|
||||
|
||||
self.d_out = d_out
|
||||
self.num_heads = num_heads
|
||||
self.head_dim = d_out // num_heads # Reduce the projection dim to match desired output dim
|
||||
|
||||
self.W_query = nn.Linear(d_in, d_out, bias=qkv_bias)
|
||||
self.W_key = nn.Linear(d_in, d_out, bias=qkv_bias)
|
||||
self.W_value = nn.Linear(d_in, d_out, bias=qkv_bias)
|
||||
self.out_proj = nn.Linear(d_out, d_out) # Linear layer to combine head outputs
|
||||
self.dropout = nn.Dropout(dropout)
|
||||
self.register_buffer('mask', torch.triu(torch.ones(block_size, block_size), diagonal=1))
|
||||
|
||||
def forward(self, x):
|
||||
b, num_tokens, d_in = x.shape
|
||||
|
||||
keys = self.W_key(x) # Shape: (b, num_tokens, d_out)
|
||||
queries = self.W_query(x)
|
||||
values = self.W_value(x)
|
||||
|
||||
# We implicitly split the matrix by adding a `num_heads` dimension
|
||||
# Unroll last dim: (b, num_tokens, d_out) -> (b, num_tokens, num_heads, head_dim)
|
||||
keys = keys.view(b, num_tokens, self.num_heads, self.head_dim)
|
||||
values = values.view(b, num_tokens, self.num_heads, self.head_dim)
|
||||
queries = queries.view(b, num_tokens, self.num_heads, self.head_dim)
|
||||
|
||||
# Transpose: (b, num_tokens, num_heads, head_dim) -> (b, num_heads, num_tokens, head_dim)
|
||||
keys = keys.transpose(1, 2)
|
||||
queries = queries.transpose(1, 2)
|
||||
values = values.transpose(1, 2)
|
||||
|
||||
# Compute scaled dot-product attention (aka self-attention) with a causal mask
|
||||
attn_scores = queries @ keys.transpose(2, 3) # Dot product for each head
|
||||
|
||||
# Original mask truncated to the number of tokens and converted to boolean
|
||||
mask_bool = self.mask.bool()[:num_tokens, :num_tokens]
|
||||
|
||||
# Use the mask to fill attention scores
|
||||
attn_scores.masked_fill_(mask_bool, -torch.inf)
|
||||
|
||||
attn_weights = torch.softmax(attn_scores / keys.shape[-1]**0.5, dim=-1)
|
||||
attn_weights = self.dropout(attn_weights)
|
||||
|
||||
# Shape: (b, num_tokens, num_heads, head_dim)
|
||||
context_vec = (attn_weights @ values).transpose(1, 2)
|
||||
|
||||
# Combine heads, where self.d_out = self.num_heads * self.head_dim
|
||||
context_vec = context_vec.contiguous().view(b, num_tokens, self.d_out)
|
||||
context_vec = self.out_proj(context_vec) # optional projection
|
||||
|
||||
return context_vec
|
||||
|
||||
|
||||
#####################################
|
||||
# Chapter 4
|
||||
#####################################
|
||||
class LayerNorm(nn.Module):
|
||||
def __init__(self, emb_dim):
|
||||
super().__init__()
|
||||
self.eps = 1e-5
|
||||
self.scale = nn.Parameter(torch.ones(emb_dim))
|
||||
self.shift = nn.Parameter(torch.zeros(emb_dim))
|
||||
|
||||
def forward(self, x):
|
||||
mean = x.mean(dim=-1, keepdim=True)
|
||||
var = x.var(dim=-1, keepdim=True, unbiased=False)
|
||||
norm_x = (x - mean) / torch.sqrt(var + self.eps)
|
||||
return self.scale * norm_x + self.shift
|
||||
|
||||
|
||||
class GELU(nn.Module):
|
||||
def __init__(self):
|
||||
super().__init__()
|
||||
|
||||
def forward(self, x):
|
||||
return 0.5 * x * (1 + torch.tanh(
|
||||
torch.sqrt(torch.tensor(2.0 / torch.pi)) *
|
||||
(x + 0.044715 * torch.pow(x, 3))
|
||||
))
|
||||
|
||||
|
||||
class FeedForward(nn.Module):
|
||||
def __init__(self, cfg):
|
||||
super().__init__()
|
||||
self.layers = nn.Sequential(
|
||||
nn.Linear(cfg["emb_dim"], 4 * cfg["emb_dim"]),
|
||||
GELU(),
|
||||
nn.Linear(4 * cfg["emb_dim"], cfg["emb_dim"]),
|
||||
nn.Dropout(cfg["drop_rate"])
|
||||
)
|
||||
|
||||
def forward(self, x):
|
||||
return self.layers(x)
|
||||
|
||||
|
||||
class TransformerBlock(nn.Module):
|
||||
def __init__(self, cfg):
|
||||
super().__init__()
|
||||
self.att = MultiHeadAttention(
|
||||
d_in=cfg["emb_dim"],
|
||||
d_out=cfg["emb_dim"],
|
||||
block_size=cfg["ctx_len"],
|
||||
num_heads=cfg["n_heads"],
|
||||
dropout=cfg["drop_rate"],
|
||||
qkv_bias=cfg["qkv_bias"])
|
||||
self.ff = FeedForward(cfg)
|
||||
self.norm1 = LayerNorm(cfg["emb_dim"])
|
||||
self.norm2 = LayerNorm(cfg["emb_dim"])
|
||||
self.drop_resid = nn.Dropout(cfg["drop_rate"])
|
||||
|
||||
def forward(self, x):
|
||||
# Shortcut connection for attention block
|
||||
shortcut = x
|
||||
x = self.norm1(x)
|
||||
x = self.att(x) # Shape [batch_size, num_tokens, emb_size]
|
||||
x = self.drop_resid(x)
|
||||
x = x + shortcut # Add the original input back
|
||||
|
||||
# Shortcut connection for feed-forward block
|
||||
shortcut = x
|
||||
x = self.norm2(x)
|
||||
x = self.ff(x)
|
||||
x = self.drop_resid(x)
|
||||
x = x + shortcut # Add the original input back
|
||||
|
||||
return x
|
||||
|
||||
|
||||
class GPTModel(nn.Module):
|
||||
def __init__(self, cfg):
|
||||
super().__init__()
|
||||
self.tok_emb = nn.Embedding(cfg["vocab_size"], cfg["emb_dim"])
|
||||
self.pos_emb = nn.Embedding(cfg["ctx_len"], cfg["emb_dim"])
|
||||
self.drop_emb = nn.Dropout(cfg["drop_rate"])
|
||||
|
||||
self.trf_blocks = nn.Sequential(
|
||||
*[TransformerBlock(cfg) for _ in range(cfg["n_layers"])])
|
||||
|
||||
self.final_norm = LayerNorm(cfg["emb_dim"])
|
||||
self.out_head = nn.Linear(cfg["emb_dim"], cfg["vocab_size"], bias=False)
|
||||
|
||||
def forward(self, in_idx):
|
||||
batch_size, seq_len = in_idx.shape
|
||||
tok_embeds = self.tok_emb(in_idx)
|
||||
pos_embeds = self.pos_emb(torch.arange(seq_len, device=in_idx.device))
|
||||
x = tok_embeds + pos_embeds # Shape [batch_size, num_tokens, emb_size]
|
||||
x = self.drop_emb(x)
|
||||
x = self.trf_blocks(x)
|
||||
x = self.final_norm(x)
|
||||
logits = self.out_head(x)
|
||||
return logits
|
||||
|
||||
|
||||
def generate_text_simple(model, idx, max_new_tokens, context_size):
|
||||
# idx is (B, T) array of indices in the current context
|
||||
for _ in range(max_new_tokens):
|
||||
|
||||
# Crop current context if it exceeds the supported context size
|
||||
# E.g., if LLM supports only 5 tokens, and the context size is 10
|
||||
# then only the last 5 tokens are used as context
|
||||
idx_cond = idx[:, -context_size:]
|
||||
|
||||
# Get the predictions
|
||||
with torch.no_grad():
|
||||
logits = model(idx_cond)
|
||||
|
||||
# Focus only on the last time step
|
||||
# (batch, n_token, vocab_size) becomes (batch, vocab_size)
|
||||
logits = logits[:, -1, :]
|
||||
|
||||
# Get the idx of the vocab entry with the highest logits value
|
||||
idx_next = torch.argmax(logits, dim=-1, keepdim=True) # (batch, 1)
|
||||
|
||||
# Append sampled index to the running sequence
|
||||
idx = torch.cat((idx, idx_next), dim=1) # (batch, n_tokens+1)
|
||||
|
||||
return idx
|
||||
|
||||
|
||||
if __name__ == "__main__":
|
||||
|
||||
GPT_CONFIG_124M = {
|
||||
"vocab_size": 50257, # Vocabulary size
|
||||
"ctx_len": 1024, # Context length
|
||||
"emb_dim": 768, # Embedding dimension
|
||||
"n_heads": 12, # Number of attention heads
|
||||
"n_layers": 12, # Number of layers
|
||||
"drop_rate": 0.1, # Dropout rate
|
||||
"qkv_bias": False # Query-Key-Value bias
|
||||
}
|
||||
|
||||
torch.manual_seed(123)
|
||||
model = GPTModel(GPT_CONFIG_124M)
|
||||
model.eval() # disable dropout
|
||||
|
||||
start_context = "Hello, I am"
|
||||
|
||||
tokenizer = tiktoken.get_encoding("gpt2")
|
||||
encoded = tokenizer.encode(start_context)
|
||||
encoded_tensor = torch.tensor(encoded).unsqueeze(0)
|
||||
|
||||
print(f"\n{50*'='}\n{22*' '}IN\n{50*'='}")
|
||||
print("\nInput text:", start_context)
|
||||
print("Encoded input text:", encoded)
|
||||
print("encoded_tensor.shape:", encoded_tensor.shape)
|
||||
|
||||
out = generate_text_simple(
|
||||
model=model,
|
||||
idx=encoded_tensor,
|
||||
max_new_tokens=10,
|
||||
context_size=GPT_CONFIG_124M["ctx_len"]
|
||||
)
|
||||
decoded_text = tokenizer.decode(out.squeeze(0).tolist())
|
||||
|
||||
print(f"\n\n{50*'='}\n{22*' '}OUT\n{50*'='}")
|
||||
print("\nOutput:", out)
|
||||
print("Output length:", len(out[0]))
|
||||
print("Output text:", decoded_text)
|
||||
@@ -0,0 +1,165 @@
|
||||
I HAD always thought Jack Gisburn rather a cheap genius--though a good fellow enough--so it was no great surprise to me to hear that, in the height of his glory, he had dropped his painting, married a rich widow, and established himself in a villa on the Riviera. (Though I rather thought it would have been Rome or Florence.)
|
||||
|
||||
"The height of his glory"--that was what the women called it. I can hear Mrs. Gideon Thwing--his last Chicago sitter--deploring his unaccountable abdication. "Of course it's going to send the value of my picture 'way up; but I don't think of that, Mr. Rickham--the loss to Arrt is all I think of." The word, on Mrs. Thwing's lips, multiplied its _rs_ as though they were reflected in an endless vista of mirrors. And it was not only the Mrs. Thwings who mourned. Had not the exquisite Hermia Croft, at the last Grafton Gallery show, stopped me before Gisburn's "Moon-dancers" to say, with tears in her eyes: "We shall not look upon its like again"?
|
||||
|
||||
Well!--even through the prism of Hermia's tears I felt able to face the fact with equanimity. Poor Jack Gisburn! The women had made him--it was fitting that they should mourn him. Among his own sex fewer regrets were heard, and in his own trade hardly a murmur. Professional jealousy? Perhaps. If it were, the honour of the craft was vindicated by little Claude Nutley, who, in all good faith, brought out in the Burlington a very handsome "obituary" on Jack--one of those showy articles stocked with random technicalities that I have heard (I won't say by whom) compared to Gisburn's painting. And so--his resolve being apparently irrevocable--the discussion gradually died out, and, as Mrs. Thwing had predicted, the price of "Gisburns" went up.
|
||||
|
||||
It was not till three years later that, in the course of a few weeks' idling on the Riviera, it suddenly occurred to me to wonder why Gisburn had given up his painting. On reflection, it really was a tempting problem. To accuse his wife would have been too easy--his fair sitters had been denied the solace of saying that Mrs. Gisburn had "dragged him down." For Mrs. Gisburn--as such--had not existed till nearly a year after Jack's resolve had been taken. It might be that he had married her--since he liked his ease--because he didn't want to go on painting; but it would have been hard to prove that he had given up his painting because he had married her.
|
||||
|
||||
Of course, if she had not dragged him down, she had equally, as Miss Croft contended, failed to "lift him up"--she had not led him back to the easel. To put the brush into his hand again--what a vocation for a wife! But Mrs. Gisburn appeared to have disdained it--and I felt it might be interesting to find out why.
|
||||
|
||||
The desultory life of the Riviera lends itself to such purely academic speculations; and having, on my way to Monte Carlo, caught a glimpse of Jack's balustraded terraces between the pines, I had myself borne thither the next day.
|
||||
|
||||
I found the couple at tea beneath their palm-trees; and Mrs. Gisburn's welcome was so genial that, in the ensuing weeks, I claimed it frequently. It was not that my hostess was "interesting": on that point I could have given Miss Croft the fullest reassurance. It was just because she was _not_ interesting--if I may be pardoned the bull--that I found her so. For Jack, all his life, had been surrounded by interesting women: they had fostered his art, it had been reared in the hot-house of their adulation. And it was therefore instructive to note what effect the "deadening atmosphere of mediocrity" (I quote Miss Croft) was having on him.
|
||||
|
||||
I have mentioned that Mrs. Gisburn was rich; and it was immediately perceptible that her husband was extracting from this circumstance a delicate but substantial satisfaction. It is, as a rule, the people who scorn money who get most out of it; and Jack's elegant disdain of his wife's big balance enabled him, with an appearance of perfect good-breeding, to transmute it into objects of art and luxury. To the latter, I must add, he remained relatively indifferent; but he was buying Renaissance bronzes and eighteenth-century pictures with a discrimination that bespoke the amplest resources.
|
||||
|
||||
"Money's only excuse is to put beauty into circulation," was one of the axioms he laid down across the Sevres and silver of an exquisitely appointed luncheon-table, when, on a later day, I had again run over from Monte Carlo; and Mrs. Gisburn, beaming on him, added for my enlightenment: "Jack is so morbidly sensitive to every form of beauty."
|
||||
|
||||
Poor Jack! It had always been his fate to have women say such things of him: the fact should be set down in extenuation. What struck me now was that, for the first time, he resented the tone. I had seen him, so often, basking under similar tributes--was it the conjugal note that robbed them of their savour? No--for, oddly enough, it became apparent that he was fond of Mrs. Gisburn--fond enough not to see her absurdity. It was his own absurdity he seemed to be wincing under--his own attitude as an object for garlands and incense.
|
||||
|
||||
"My dear, since I've chucked painting people don't say that stuff about me--they say it about Victor Grindle," was his only protest, as he rose from the table and strolled out onto the sunlit terrace.
|
||||
|
||||
I glanced after him, struck by his last word. Victor Grindle was, in fact, becoming the man of the moment--as Jack himself, one might put it, had been the man of the hour. The younger artist was said to have formed himself at my friend's feet, and I wondered if a tinge of jealousy underlay the latter's mysterious abdication. But no--for it was not till after that event that the _rose Dubarry_ drawing-rooms had begun to display their "Grindles."
|
||||
|
||||
I turned to Mrs. Gisburn, who had lingered to give a lump of sugar to her spaniel in the dining-room.
|
||||
|
||||
"Why _has_ he chucked painting?" I asked abruptly.
|
||||
|
||||
She raised her eyebrows with a hint of good-humoured surprise.
|
||||
|
||||
"Oh, he doesn't _have_ to now, you know; and I want him to enjoy himself," she said quite simply.
|
||||
|
||||
I looked about the spacious white-panelled room, with its _famille-verte_ vases repeating the tones of the pale damask curtains, and its eighteenth-century pastels in delicate faded frames.
|
||||
|
||||
"Has he chucked his pictures too? I haven't seen a single one in the house."
|
||||
|
||||
A slight shade of constraint crossed Mrs. Gisburn's open countenance. "It's his ridiculous modesty, you know. He says they're not fit to have about; he's sent them all away except one--my portrait--and that I have to keep upstairs."
|
||||
|
||||
His ridiculous modesty--Jack's modesty about his pictures? My curiosity was growing like the bean-stalk. I said persuasively to my hostess: "I must really see your portrait, you know."
|
||||
|
||||
She glanced out almost timorously at the terrace where her husband, lounging in a hooded chair, had lit a cigar and drawn the Russian deerhound's head between his knees.
|
||||
|
||||
"Well, come while he's not looking," she said, with a laugh that tried to hide her nervousness; and I followed her between the marble Emperors of the hall, and up the wide stairs with terra-cotta nymphs poised among flowers at each landing.
|
||||
|
||||
In the dimmest corner of her boudoir, amid a profusion of delicate and distinguished objects, hung one of the familiar oval canvases, in the inevitable garlanded frame. The mere outline of the frame called up all Gisburn's past!
|
||||
|
||||
Mrs. Gisburn drew back the window-curtains, moved aside a _jardiniere_ full of pink azaleas, pushed an arm-chair away, and said: "If you stand here you can just manage to see it. I had it over the mantel-piece, but he wouldn't let it stay."
|
||||
|
||||
Yes--I could just manage to see it--the first portrait of Jack's I had ever had to strain my eyes over! Usually they had the place of honour--say the central panel in a pale yellow or _rose Dubarry_ drawing-room, or a monumental easel placed so that it took the light through curtains of old Venetian point. The more modest place became the picture better; yet, as my eyes grew accustomed to the half-light, all the characteristic qualities came out--all the hesitations disguised as audacities, the tricks of prestidigitation by which, with such consummate skill, he managed to divert attention from the real business of the picture to some pretty irrelevance of detail. Mrs. Gisburn, presenting a neutral surface to work on--forming, as it were, so inevitably the background of her own picture--had lent herself in an unusual degree to the display of this false virtuosity. The picture was one of Jack's "strongest," as his admirers would have put it--it represented, on his part, a swelling of muscles, a congesting of veins, a balancing, straddling and straining, that reminded one of the circus-clown's ironic efforts to lift a feather. It met, in short, at every point the demand of lovely woman to be painted "strongly" because she was tired of being painted "sweetly"--and yet not to lose an atom of the sweetness.
|
||||
|
||||
"It's the last he painted, you know," Mrs. Gisburn said with pardonable pride. "The last but one," she corrected herself--"but the other doesn't count, because he destroyed it."
|
||||
|
||||
"Destroyed it?" I was about to follow up this clue when I heard a footstep and saw Jack himself on the threshold.
|
||||
|
||||
As he stood there, his hands in the pockets of his velveteen coat, the thin brown waves of hair pushed back from his white forehead, his lean sunburnt cheeks furrowed by a smile that lifted the tips of a self-confident moustache, I felt to what a degree he had the same quality as his pictures--the quality of looking cleverer than he was.
|
||||
|
||||
His wife glanced at him deprecatingly, but his eyes travelled past her to the portrait.
|
||||
|
||||
"Mr. Rickham wanted to see it," she began, as if excusing herself. He shrugged his shoulders, still smiling.
|
||||
|
||||
"Oh, Rickham found me out long ago," he said lightly; then, passing his arm through mine: "Come and see the rest of the house."
|
||||
|
||||
He showed it to me with a kind of naive suburban pride: the bath-rooms, the speaking-tubes, the dress-closets, the trouser-presses--all the complex simplifications of the millionaire's domestic economy. And whenever my wonder paid the expected tribute he said, throwing out his chest a little: "Yes, I really don't see how people manage to live without that."
|
||||
|
||||
Well--it was just the end one might have foreseen for him. Only he was, through it all and in spite of it all--as he had been through, and in spite of, his pictures--so handsome, so charming, so disarming, that one longed to cry out: "Be dissatisfied with your leisure!" as once one had longed to say: "Be dissatisfied with your work!"
|
||||
|
||||
But, with the cry on my lips, my diagnosis suffered an unexpected check.
|
||||
|
||||
"This is my own lair," he said, leading me into a dark plain room at the end of the florid vista. It was square and brown and leathery: no "effects"; no bric-a-brac, none of the air of posing for reproduction in a picture weekly--above all, no least sign of ever having been used as a studio.
|
||||
|
||||
The fact brought home to me the absolute finality of Jack's break with his old life.
|
||||
|
||||
"Don't you ever dabble with paint any more?" I asked, still looking about for a trace of such activity.
|
||||
|
||||
"Never," he said briefly.
|
||||
|
||||
"Or water-colour--or etching?"
|
||||
|
||||
His confident eyes grew dim, and his cheeks paled a little under their handsome sunburn.
|
||||
|
||||
"Never think of it, my dear fellow--any more than if I'd never touched a brush."
|
||||
|
||||
And his tone told me in a flash that he never thought of anything else.
|
||||
|
||||
I moved away, instinctively embarrassed by my unexpected discovery; and as I turned, my eye fell on a small picture above the mantel-piece--the only object breaking the plain oak panelling of the room.
|
||||
|
||||
"Oh, by Jove!" I said.
|
||||
|
||||
It was a sketch of a donkey--an old tired donkey, standing in the rain under a wall.
|
||||
|
||||
"By Jove--a Stroud!" I cried.
|
||||
|
||||
He was silent; but I felt him close behind me, breathing a little quickly.
|
||||
|
||||
"What a wonder! Made with a dozen lines--but on everlasting foundations. You lucky chap, where did you get it?"
|
||||
|
||||
He answered slowly: "Mrs. Stroud gave it to me."
|
||||
|
||||
"Ah--I didn't know you even knew the Strouds. He was such an inflexible hermit."
|
||||
|
||||
"I didn't--till after. . . . She sent for me to paint him when he was dead."
|
||||
|
||||
"When he was dead? You?"
|
||||
|
||||
I must have let a little too much amazement escape through my surprise, for he answered with a deprecating laugh: "Yes--she's an awful simpleton, you know, Mrs. Stroud. Her only idea was to have him done by a fashionable painter--ah, poor Stroud! She thought it the surest way of proclaiming his greatness--of forcing it on a purblind public. And at the moment I was _the_ fashionable painter."
|
||||
|
||||
"Ah, poor Stroud--as you say. Was _that_ his history?"
|
||||
|
||||
"That was his history. She believed in him, gloried in him--or thought she did. But she couldn't bear not to have all the drawing-rooms with her. She couldn't bear the fact that, on varnishing days, one could always get near enough to see his pictures. Poor woman! She's just a fragment groping for other fragments. Stroud is the only whole I ever knew."
|
||||
|
||||
"You ever knew? But you just said--"
|
||||
|
||||
Gisburn had a curious smile in his eyes.
|
||||
|
||||
"Oh, I knew him, and he knew me--only it happened after he was dead."
|
||||
|
||||
I dropped my voice instinctively. "When she sent for you?"
|
||||
|
||||
"Yes--quite insensible to the irony. She wanted him vindicated--and by me!"
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||||
He laughed again, and threw back his head to look up at the sketch of the donkey. "There were days when I couldn't look at that thing--couldn't face it. But I forced myself to put it here; and now it's cured me--cured me. That's the reason why I don't dabble any more, my dear Rickham; or rather Stroud himself is the reason."
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||||
For the first time my idle curiosity about my companion turned into a serious desire to understand him better.
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||||
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||||
"I wish you'd tell me how it happened," I said.
|
||||
|
||||
He stood looking up at the sketch, and twirling between his fingers a cigarette he had forgotten to light. Suddenly he turned toward me.
|
||||
|
||||
"I'd rather like to tell you--because I've always suspected you of loathing my work."
|
||||
|
||||
I made a deprecating gesture, which he negatived with a good-humoured shrug.
|
||||
|
||||
"Oh, I didn't care a straw when I believed in myself--and now it's an added tie between us!"
|
||||
|
||||
He laughed slightly, without bitterness, and pushed one of the deep arm-chairs forward. "There: make yourself comfortable--and here are the cigars you like."
|
||||
|
||||
He placed them at my elbow and continued to wander up and down the room, stopping now and then beneath the picture.
|
||||
|
||||
"How it happened? I can tell you in five minutes--and it didn't take much longer to happen. . . . I can remember now how surprised and pleased I was when I got Mrs. Stroud's note. Of course, deep down, I had always _felt_ there was no one like him--only I had gone with the stream, echoed the usual platitudes about him, till I half got to think he was a failure, one of the kind that are left behind. By Jove, and he _was_ left behind--because he had come to stay! The rest of us had to let ourselves be swept along or go under, but he was high above the current--on everlasting foundations, as you say.
|
||||
|
||||
"Well, I went off to the house in my most egregious mood--rather moved, Lord forgive me, at the pathos of poor Stroud's career of failure being crowned by the glory of my painting him! Of course I meant to do the picture for nothing--I told Mrs. Stroud so when she began to stammer something about her poverty. I remember getting off a prodigious phrase about the honour being _mine_--oh, I was princely, my dear Rickham! I was posing to myself like one of my own sitters.
|
||||
|
||||
"Then I was taken up and left alone with him. I had sent all my traps in advance, and I had only to set up the easel and get to work. He had been dead only twenty-four hours, and he died suddenly, of heart disease, so that there had been no preliminary work of destruction--his face was clear and untouched. I had met him once or twice, years before, and thought him insignificant and dingy. Now I saw that he was superb.
|
||||
|
||||
"I was glad at first, with a merely aesthetic satisfaction: glad to have my hand on such a 'subject.' Then his strange life-likeness began to affect me queerly--as I blocked the head in I felt as if he were watching me do it. The sensation was followed by the thought: if he _were_ watching me, what would he say to my way of working? My strokes began to go a little wild--I felt nervous and uncertain.
|
||||
|
||||
"Once, when I looked up, I seemed to see a smile behind his close grayish beard--as if he had the secret, and were amusing himself by holding it back from me. That exasperated me still more. The secret? Why, I had a secret worth twenty of his! I dashed at the canvas furiously, and tried some of my bravura tricks. But they failed me, they crumbled. I saw that he wasn't watching the showy bits--I couldn't distract his attention; he just kept his eyes on the hard passages between. Those were the ones I had always shirked, or covered up with some lying paint. And how he saw through my lies!
|
||||
|
||||
"I looked up again, and caught sight of that sketch of the donkey hanging on the wall near his bed. His wife told me afterward it was the last thing he had done--just a note taken with a shaking hand, when he was down in Devonshire recovering from a previous heart attack. Just a note! But it tells his whole history. There are years of patient scornful persistence in every line. A man who had swum with the current could never have learned that mighty up-stream stroke. . . .
|
||||
|
||||
"I turned back to my work, and went on groping and muddling; then I looked at the donkey again. I saw that, when Stroud laid in the first stroke, he knew just what the end would be. He had possessed his subject, absorbed it, recreated it. When had I done that with any of my things? They hadn't been born of me--I had just adopted them. . . .
|
||||
|
||||
"Hang it, Rickham, with that face watching me I couldn't do another stroke. The plain truth was, I didn't know where to put it--_I had never known_. Only, with my sitters and my public, a showy splash of colour covered up the fact--I just threw paint into their faces. . . . Well, paint was the one medium those dead eyes could see through--see straight to the tottering foundations underneath. Don't you know how, in talking a foreign language, even fluently, one says half the time not what one wants to but what one can? Well--that was the way I painted; and as he lay there and watched me, the thing they called my 'technique' collapsed like a house of cards. He didn't sneer, you understand, poor Stroud--he just lay there quietly watching, and on his lips, through the gray beard, I seemed to hear the question: 'Are you sure you know where you're coming out?'
|
||||
|
||||
"If I could have painted that face, with that question on it, I should have done a great thing. The next greatest thing was to see that I couldn't--and that grace was given me. But, oh, at that minute, Rickham, was there anything on earth I wouldn't have given to have Stroud alive before me, and to hear him say: 'It's not too late--I'll show you how'?
|
||||
|
||||
"It _was_ too late--it would have been, even if he'd been alive. I packed up my traps, and went down and told Mrs. Stroud. Of course I didn't tell her _that_--it would have been Greek to her. I simply said I couldn't paint him, that I was too moved. She rather liked the idea--she's so romantic! It was that that made her give me the donkey. But she was terribly upset at not getting the portrait--she did so want him 'done' by some one showy! At first I was afraid she wouldn't let me off--and at my wits' end I suggested Grindle. Yes, it was I who started Grindle: I told Mrs. Stroud he was the 'coming' man, and she told somebody else, and so it got to be true. . . . And he painted Stroud without wincing; and she hung the picture among her husband's things. . . ."
|
||||
|
||||
He flung himself down in the arm-chair near mine, laid back his head, and clasping his arms beneath it, looked up at the picture above the chimney-piece.
|
||||
|
||||
"I like to fancy that Stroud himself would have given it to me, if he'd been able to say what he thought that day."
|
||||
|
||||
And, in answer to a question I put half-mechanically--"Begin again?" he flashed out. "When the one thing that brings me anywhere near him is that I knew enough to leave off?"
|
||||
|
||||
He stood up and laid his hand on my shoulder with a laugh. "Only the irony of it is that I _am_ still painting--since Grindle's doing it for me! The Strouds stand alone, and happen once--but there's no exterminating our kind of art."
|
||||
@@ -0,0 +1,7 @@
|
||||
# Chapter 5: 使用未标记数据进行预训练
|
||||
|
||||
- [01_main-chapter-code](01_main-chapter-code) 主要章节代码
|
||||
- [02_alternative_weight_loading](02_alternative_weight_loading) 从其他途径下载GPT模型的代码防止OpenAI某天不开源该模型权重了
|
||||
- [03_bonus_pretraining_on_gutenberg](03_bonus_pretraining_on_gutenberg) 在整个Gutenberg项目语料库上进行预训练的代码
|
||||
- [04_learning_rate_schedulers](04_learning_rate_schedulers)实现更复杂的训练函数，包括学习率调整和梯度剪裁
|
||||
- [05_hparam_tuning](05_hparam_tuning) 可选的超参数调优脚本
|
||||
Reference in New Issue
Block a user