update some explain of the code

This commit is contained in:
gongjy
2024-09-20 17:04:16 +08:00
parent b4170e3766
commit ee218402cd
13 changed files with 19932 additions and 338 deletions
+45 -45
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@@ -1,58 +1,58 @@
from transformers import PretrainedConfig
from typing import List
# 定义 LMConfig 类,继承自 PretrainedConfig
class LMConfig(PretrainedConfig):
model_type = "minimind" # 设置模型类型为 "minimind"
model_type = "minimind"
def __init__(
self,
dim: int = 512, # 模型维度,默认为 512
n_layers: int = 8, # Transformer 层数,默认为 8
n_heads: int = 16, # 注意力头数,默认为 16
n_kv_heads: int = 8, # KV 头数,默认为 8
vocab_size: int = 6400, # 词汇表大小,默认为 6400
hidden_dim: int = None, # 隐藏层维度,默认为 None
multiple_of: int = 64, # 隐藏层维度的倍数,默认为 64
norm_eps: float = 1e-5, # 归一化层的 epsilon 值,默认为 1e-5
max_seq_len: int = 512, # 最大序列长度,默认为 512
dropout: float = 0.0, # Dropout 概率,默认为 0.0
flash_attn: bool = True, # 是否使用 Flash Attention,默认为 True
dim: int = 768,
n_layers: int = 16,
n_heads: int = 16,
n_kv_heads: int = 8,
vocab_size: int = 6400,
hidden_dim: int = None,
multiple_of: int = 64,
norm_eps: float = 1e-5,
max_seq_len: int = 512,
dropout: float = 0.0,
flash_attn: bool = True,
####################################################
# 以下是 MOEMixture of Experts)的特定配置
# use_moe 为 False 时,以下配置无效
# Here are the specific configurations of MOE
# When use_moe is false, the following is invalid
####################################################
use_moe: bool = False, # 是否使用 MOE,默认为 False
num_experts_per_tok=2, # 每个 token 选择的专家数量,默认为 2
n_routed_experts=4, # 总的专家数量,默认为 4
n_shared_experts: bool = True, # 是否使用共享专家,默认为 True
scoring_func='softmax', # 评分函数,默认为 'softmax'
aux_loss_alpha=0.01, # 辅助损失的 alpha 参数,默认为 0.01
seq_aux=True, # 是否在序列级别上计算辅助损失,默认为 True
norm_topk_prob=True, # 是否标准化 top-k 概率,默认为 True
use_moe: bool = False,
num_experts_per_tok=2,
n_routed_experts=4,
n_shared_experts: bool = True,
scoring_func='softmax',
aux_loss_alpha=0.01,
seq_aux=True,
norm_topk_prob=True,
**kwargs,
):
self.dim = dim # 设置模型维度
self.n_layers = n_layers # 设置 Transformer 层数
self.n_heads = n_heads # 设置注意力头数
self.n_kv_heads = n_kv_heads # 设置 KV 头数
self.vocab_size = vocab_size # 设置词汇表大小
self.hidden_dim = hidden_dim # 设置隐藏层维度
self.multiple_of = multiple_of # 设置隐藏层维度的倍数
self.norm_eps = norm_eps # 设置归一化层的 epsilon 值
self.max_seq_len = max_seq_len # 设置最大序列长度
self.dropout = dropout # 设置 Dropout 概率
self.flash_attn = flash_attn # 设置是否使用 Flash Attention
self.dim = dim
self.n_layers = n_layers
self.n_heads = n_heads
self.n_kv_heads = n_kv_heads
self.vocab_size = vocab_size
self.hidden_dim = hidden_dim
self.multiple_of = multiple_of
self.norm_eps = norm_eps
self.max_seq_len = max_seq_len
self.dropout = dropout
self.flash_attn = flash_attn
####################################################
# 以下是 MOEMixture of Experts)的特定配置
# use_moe 为 False 时,以下配置无效
# Here are the specific configurations of MOE
# When use_moe is false, the following is invalid
####################################################
self.use_moe = use_moe # 设置是否使用 MOE
self.num_experts_per_tok = num_experts_per_tok # 设置每个 token 选择的专家数量
self.n_routed_experts = n_routed_experts # 设置总的专家数量
self.n_shared_experts = n_shared_experts # 设置是否使用共享专家
self.scoring_func = scoring_func # 设置评分函数
self.aux_loss_alpha = aux_loss_alpha # 设置辅助损失的 alpha 参数
self.seq_aux = seq_aux # 设置是否在序列级别上计算辅助损失
self.norm_topk_prob = norm_topk_prob # 设置是否标准化 top-k 概率
super().__init__(**kwargs) # 调用父类 PretrainedConfig 的初始化方法
self.use_moe = use_moe
self.num_experts_per_tok = num_experts_per_tok # 每个token选择的专家数量
self.n_routed_experts = n_routed_experts # 总的专家数量
self.n_shared_experts = n_shared_experts # 共享专家
self.scoring_func = scoring_func # 评分函数,默认为'softmax'
self.aux_loss_alpha = aux_loss_alpha # 辅助损失的alpha参数
self.seq_aux = seq_aux # 是否在序列级别上计算辅助损失
self.norm_topk_prob = norm_topk_prob # 是否标准化top-k概率
super().__init__(**kwargs)
+41 -41
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@@ -9,79 +9,79 @@ import torch
from sklearn.model_selection import train_test_split
import os
os.environ["TOKENIZERS_PARALLELISM"] = "false" # 禁用 tokenizer 的并行处理
os.environ["TOKENIZERS_PARALLELISM"] = "false"
# 定义 PretrainDataset 类,继承自 Dataset
class PretrainDataset(Dataset):
def __init__(self, data_path_lst, max_length=512, memmap=False):
super().__init__()
# 如果使用内存映射(memmap
#
if memmap:
with open(data_path_lst[0], 'r') as f:
nbytes = f.seek(0, 2) # 获取文件总字节数
flen = f.tell() // np.dtype('uint16').itemsize # 计算文件长度
self.data = np.memmap(data_path_lst[0], dtype=np.dtype('uint16'), shape=(flen // max_length, max_length)) # 使用内存映射加载数据
nbytes = f.seek(0, 2)
flen = f.tell() // np.dtype('uint16').itemsize
self.data = np.memmap(data_path_lst[0], dtype=np.dtype('uint16'), shape=(flen // max_length, max_length))
else:
data_lst = []
for data_path in data_path_lst:
with open(data_path, 'rb') as f:
data = np.fromfile(f, dtype=np.uint16) # 从文件中读取数据
data = np.fromfile(f, dtype=np.uint16)
data_lst.append(data)
data = np.concatenate(data_lst) # 合并所有数据
data = data[:max_length * int(len(data) / max_length)] # 截取数据
# np.random.shuffle(data) # 打乱数据(注释掉了)
self.data = data.reshape(-1, max_length) # 将数据重塑为 (样本数, 最大长度) 的形状
# 打印数据形状
data = np.concatenate(data_lst)
data = data[:max_length * int(len(data) / max_length)]
# np.random.shuffle(data)
self.data = data.reshape(-1, max_length)
#
print("memmap:{} train data.shape:{}".format(memmap, self.data.shape))
print("downloading finished.....")
def __len__(self):
return self.data.shape[0] # 返回数据集的长度
return self.data.shape[0]
def __getitem__(self, index: int):
# 获取指定索引的样本
#
sample = self.data[index]
X = np.array(sample[:-1]).astype(np.int64) # 输入数据(去掉最后一个 token)
Y = np.array(sample[1:]).astype(np.int64) # 目标数据(去掉第一个 token
X = np.array(sample[:-1]).astype(np.int64)
Y = np.array(sample[1:]).astype(np.int64)
return torch.from_numpy(X), torch.from_numpy(Y)
return torch.from_numpy(X), torch.from_numpy(Y) # 返回 PyTorch 张量
# 定义 SFTDataset 类,继承自 Dataset
class SFTDataset(Dataset):
def __init__(self, df, tokenizer, max_length=1024, prompt_max_len=512, answer_max_len=256):
super().__init__()
self.df = df # 数据框
self.max_length = max_length # 最大序列长度
self.prompt_max_len = prompt_max_len # 提示的最大长度
self.answer_max_len = answer_max_len # 回答的最大长度
self.df = df
self.max_length = max_length
self.prompt_max_len = prompt_max_len
self.answer_max_len = answer_max_len
#
self.tokenizer = tokenizer # 分词器
self.padding = 0 # 填充 token ID
self.bos_id = self.tokenizer('<s>assistant').data['input_ids'] # 开始 token ID
self.tokenizer = tokenizer
self.padding = 0 # self.tokenizer.special_tokens['<pad>']
self.bos_id = self.tokenizer('<s>assistant').data['input_ids']
def __len__(self):
return self.df.shape[0] # 返回数据集的长度
return self.df.shape[0]
def find_sublist_index(self, main_list, sub_list) -> int:
last_index = -1
for i in range(len(main_list) - len(sub_list) + 1):
if main_list[i:i + len(sub_list)] == sub_list:
last_index = i
return last_index # 查找子列表在主列表中的最后一个索引
return last_index
def safe_eval(self, s):
try:
res = eval(s)
except Exception as e:
return []
return res # 安全地执行 eval 函数
return res
def __getitem__(self, index: int):
# 获取指定索引的样本
#
sample = self.df.iloc[index]
history = self.safe_eval(sample['history']) # 获取历史对话
q = str(sample['q']) # 获取问题
a = str(sample['a']) # 获取回答
history = self.safe_eval(sample['history'])
q = str(sample['q'])
a = str(sample['a'])
messages = []
for history_message in history:
@@ -102,29 +102,29 @@ class SFTDataset(Dataset):
messages,
tokenize=False,
add_generation_prompt=True
) # 生成新的提示
input_id = self.tokenizer(new_prompt).data['input_ids'][:self.max_length] # 分词并截取
)
input_id = self.tokenizer(new_prompt).data['input_ids'][:self.max_length]
# 实际长度
question_length = self.find_sublist_index(input_id, self.bos_id) + len(self.bos_id)
# 没满最大长度的剩余部分
padding_len = self.max_length - len(input_id)
input_id = input_id + [self.padding] * padding_len # 填充到最大长度
input_id = input_id + [self.padding] * padding_len
mask_len = len(input_id) - question_length - padding_len
# 0表示不计算损失
loss_mask = [0] * question_length + [1] * (mask_len) + [0] * padding_len
input_id = np.array(input_id)
X = np.array(input_id[:-1]).astype(np.int64) # 输入数据(去掉最后一个 token)
Y = np.array(input_id[1:]).astype(np.int64) # 目标数据(去掉第一个 token
loss_mask = np.array(loss_mask[1:]).astype(np.int64) # 损失掩码
X = np.array(input_id[:-1]).astype(np.int64)
Y = np.array(input_id[1:]).astype(np.int64)
loss_mask = np.array(loss_mask[1:]).astype(np.int64)
X_tensor = torch.from_numpy(X)
Y_tensor = torch.from_numpy(Y)
loss_mask_tensor = torch.from_numpy(loss_mask)
return X_tensor, Y_tensor, loss_mask_tensor # 返回 PyTorch 张量
return X_tensor, Y_tensor, loss_mask_tensor
# 主函数
if __name__ == "__main__":
pass
pass
+161 -172
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@@ -10,29 +10,29 @@ from torch import nn
from transformers import PreTrainedModel
from transformers.modeling_outputs import CausalLMOutputWithPast
# 定义 RMSNorm 类,实现一种归一化方法,类似于 LayerNorm,但计算方式不同
class RMSNorm(torch.nn.Module):
def __init__(self, dim: int, eps: float):
super().__init__()
self.eps = eps # 设置 epsilon,防止除零错误
self.weight = nn.Parameter(torch.ones(dim)) # 初始化权重参数
self.eps = eps
self.weight = nn.Parameter(torch.ones(dim))
def _norm(self, x):
return x * torch.rsqrt(x.pow(2).mean(-1, keepdim=True) + self.eps) # 计算 RMSNorm
return x * torch.rsqrt(x.pow(2).mean(-1, keepdim=True) + self.eps)
def forward(self, x):
output = self._norm(x.float()).type_as(x) # 应用 RMSNorm
return output * self.weight # 乘以权重参数
output = self._norm(x.float()).type_as(x)
return output * self.weight
# 定义 precompute_pos_cis 函数,用于预计算位置编码的复数形式
def precompute_pos_cis(dim: int, end: int, theta: float = 10000.0):
freqs = 1.0 / (theta ** (torch.arange(0, dim, 2)[: (dim // 2)].float() / dim)) # 计算频率
t = torch.arange(end, device=freqs.device) # 生成时间序列
freqs = torch.outer(t, freqs).float() # 计算外积
pos_cis = torch.polar(torch.ones_like(freqs), freqs) # 计算复数形式的位置编码
freqs = 1.0 / (theta ** (torch.arange(0, dim, 2)[: (dim // 2)].float() / dim))
t = torch.arange(end, device=freqs.device) # type: ignore
freqs = torch.outer(t, freqs).float() # type: ignore
pos_cis = torch.polar(torch.ones_like(freqs), freqs) # complex64
return pos_cis
# 定义 apply_rotary_emb 函数,用于应用旋转位置编码
def apply_rotary_emb(xq, xk, pos_cis):
def unite_shape(pos_cis, x):
ndim = x.ndim
@@ -41,14 +41,14 @@ def apply_rotary_emb(xq, xk, pos_cis):
shape = [d if i == 1 or i == ndim - 1 else 1 for i, d in enumerate(x.shape)]
return pos_cis.view(*shape)
xq_ = torch.view_as_complex(xq.float().reshape(*xq.shape[:-1], -1, 2)) # 将 xq 转换为复数形式
xk_ = torch.view_as_complex(xk.float().reshape(*xk.shape[:-1], -1, 2)) # 将 xk 转换为复数形式
pos_cis = unite_shape(pos_cis, xq_) # 调整 pos_cis 的形状
xq_out = torch.view_as_real(xq_ * pos_cis).flatten(3) # 应用旋转位置编码
xk_out = torch.view_as_real(xk_ * pos_cis).flatten(3) # 应用旋转位置编码
return xq_out.type_as(xq), xk_out.type_as(xk) # 返回结果
xq_ = torch.view_as_complex(xq.float().reshape(*xq.shape[:-1], -1, 2))
xk_ = torch.view_as_complex(xk.float().reshape(*xk.shape[:-1], -1, 2))
pos_cis = unite_shape(pos_cis, xq_)
xq_out = torch.view_as_real(xq_ * pos_cis).flatten(3)
xk_out = torch.view_as_real(xk_ * pos_cis).flatten(3)
return xq_out.type_as(xq), xk_out.type_as(xk)
# 定义 repeat_kv 函数,用于重复 KV 头的值
def repeat_kv(x: torch.Tensor, n_rep: int) -> torch.Tensor:
"""torch.repeat_interleave(x, dim=2, repeats=n_rep)"""
bs, slen, n_kv_heads, head_dim = x.shape
@@ -60,130 +60,130 @@ def repeat_kv(x: torch.Tensor, n_rep: int) -> torch.Tensor:
.reshape(bs, slen, n_kv_heads * n_rep, head_dim)
)
# 定义 Attention 类,实现自注意力机制
class Attention(nn.Module):
def __init__(self, args: LMConfig):
super().__init__()
self.n_kv_heads = args.n_heads if args.n_kv_heads is None else args.n_kv_heads # 设置 KV 头的数量
assert args.n_heads % self.n_kv_heads == 0 # 确保 KV 头的数量是总头数的因数
self.n_local_heads = args.n_heads # 设置本地头的数量
self.n_local_kv_heads = self.n_kv_heads # 设置本地 KV 头的数量
self.n_rep = self.n_local_heads // self.n_local_kv_heads # 计算重复次数
self.head_dim = args.dim // args.n_heads # 计算每个头的维度
self.wq = nn.Linear(args.dim, args.n_heads * self.head_dim, bias=False) # 初始化 Q 矩阵
self.wk = nn.Linear(args.dim, self.n_kv_heads * self.head_dim, bias=False) # 初始化 K 矩阵
self.wv = nn.Linear(args.dim, self.n_kv_heads * self.head_dim, bias=False) # 初始化 V 矩阵
self.wo = nn.Linear(args.n_heads * self.head_dim, args.dim, bias=False) # 初始化输出矩阵
self.k_cache, self.v_cache = None, None # 初始化 KV 缓存
self.attn_dropout = nn.Dropout(args.dropout) # 初始化注意力 dropout
self.resid_dropout = nn.Dropout(args.dropout) # 初始化残差 dropout
self.dropout = args.dropout # 设置 dropout 概率
self.flash = hasattr(torch.nn.functional, 'scaled_dot_product_attention') and args.flash_attn # 判断是否使用 Flash Attention
self.n_kv_heads = args.n_heads if args.n_kv_heads is None else args.n_kv_heads
assert args.n_heads % self.n_kv_heads == 0
self.n_local_heads = args.n_heads
self.n_local_kv_heads = self.n_kv_heads
self.n_rep = self.n_local_heads // self.n_local_kv_heads
self.head_dim = args.dim // args.n_heads
self.wq = nn.Linear(args.dim, args.n_heads * self.head_dim, bias=False)
self.wk = nn.Linear(args.dim, self.n_kv_heads * self.head_dim, bias=False)
self.wv = nn.Linear(args.dim, self.n_kv_heads * self.head_dim, bias=False)
self.wo = nn.Linear(args.n_heads * self.head_dim, args.dim, bias=False)
self.k_cache, self.v_cache = None, None
self.attn_dropout = nn.Dropout(args.dropout)
self.resid_dropout = nn.Dropout(args.dropout)
self.dropout = args.dropout
self.flash = hasattr(torch.nn.functional, 'scaled_dot_product_attention') and args.flash_attn
if not self.flash:
# print("WARNING: using slow attention. Flash Attention requires PyTorch >= 2.0")
mask = torch.full((1, 1, args.max_seq_len, args.max_seq_len), float("-inf")) # 初始化掩码
mask = torch.triu(mask, diagonal=1) # 生成上三角掩码
self.register_buffer("mask", mask) # 注册掩码
mask = torch.full((1, 1, args.max_seq_len, args.max_seq_len), float("-inf"))
mask = torch.triu(mask, diagonal=1)
self.register_buffer("mask", mask)
def forward(self, x: torch.Tensor, pos_cis: torch.Tensor, use_kv_cache=False):
bsz, seqlen, _ = x.shape
if use_kv_cache and self.eval(): # 如果使用 KV 缓存且在评估模式下
if use_kv_cache and self.eval():
if self.k_cache is None or self.k_cache.shape[1] != x.shape[1] - 1:
xq, xk, xv = self.wq(x), self.wk(x), self.wv(x) # 计算 Q, K, V
xq, xk, xv = self.wq(x), self.wk(x), self.wv(x)
else:
token = x[:, -1:, :] # 获取最后一个 token
xq = torch.cat((torch.zeros_like(x[:, :-1, :]), self.wq(token)), dim=1) # 更新 Q
xk = torch.cat((self.k_cache, self.wk(token)), dim=1) # 更新 K
xv = torch.cat((self.v_cache, self.wv(token)), dim=1) # 更新 V
token = x[:, -1:, :]
xq = torch.cat((torch.zeros_like(x[:, :-1, :]), self.wq(token)), dim=1)
xk = torch.cat((self.k_cache, self.wk(token)), dim=1)
xv = torch.cat((self.v_cache, self.wv(token)), dim=1)
self.k_cache, self.v_cache = xk, xv # 更新 KV 缓存
self.k_cache, self.v_cache = xk, xv
else:
xq, xk, xv = self.wq(x), self.wk(x), self.wv(x) # 计算 Q, K, V
xq, xk, xv = self.wq(x), self.wk(x), self.wv(x)
xq = xq.view(bsz, seqlen, self.n_local_heads, self.head_dim) # 调整 Q 的形状
xk = xk.view(bsz, seqlen, self.n_local_kv_heads, self.head_dim) # 调整 K 的形状
xv = xv.view(bsz, seqlen, self.n_local_kv_heads, self.head_dim) # 调整 V 的形状
xq = xq.view(bsz, seqlen, self.n_local_heads, self.head_dim)
xk = xk.view(bsz, seqlen, self.n_local_kv_heads, self.head_dim)
xv = xv.view(bsz, seqlen, self.n_local_kv_heads, self.head_dim)
xq, xk = apply_rotary_emb(xq, xk, pos_cis) # 应用旋转位置编码
xq, xk = apply_rotary_emb(xq, xk, pos_cis)
xk = repeat_kv(xk, self.n_rep) # 重复 K 的值
xv = repeat_kv(xv, self.n_rep) # 重复 V 的值
xk = repeat_kv(xk, self.n_rep) # (bs, seqlen, n_local_heads, head_dim)
xv = repeat_kv(xv, self.n_rep) # (bs, seqlen, n_local_heads, head_dim)
xq = xq.transpose(1, 2) # 调整 Q 的形状
xk = xk.transpose(1, 2) # 调整 K 的形状
xv = xv.transpose(1, 2) # 调整 V 的形状
xq = xq.transpose(1, 2)
xk = xk.transpose(1, 2)
xv = xv.transpose(1, 2)
if self.flash:
output = torch.nn.functional.scaled_dot_product_attention(xq, xk, xv, attn_mask=None,
dropout_p=self.dropout if self.training else 0.0,
is_causal=True) # 使用 Flash Attention
is_causal=True)
else:
scores = torch.matmul(xq, xk.transpose(2, 3)) / math.sqrt(self.head_dim) # 计算注意力分数
scores = torch.matmul(xq, xk.transpose(2, 3)) / math.sqrt(self.head_dim)
assert hasattr(self, 'mask')
scores = scores + self.mask[:, :, :seqlen, :seqlen] # 应用掩码
scores = F.softmax(scores.float(), dim=-1).type_as(xq) # 计算 softmax
scores = self.attn_dropout(scores) # 应用注意力 dropout
output = torch.matmul(scores, xv) # 计算输出
scores = scores + self.mask[:, :, :seqlen, :seqlen] # (bs, n_local_heads, seqlen, cache_len + seqlen)
scores = F.softmax(scores.float(), dim=-1).type_as(xq)
scores = self.attn_dropout(scores)
output = torch.matmul(scores, xv) # (bs, n_local_heads, seqlen, head_dim)
output = output.transpose(1, 2).contiguous().view(bsz, seqlen, -1) # 调整输出的形状
output = output.transpose(1, 2).contiguous().view(bsz, seqlen, -1)
output = self.wo(output)
output = self.resid_dropout(output)
return output
output = self.wo(output) # 应用输出矩阵
output = self.resid_dropout(output) # 应用残差 dropout
return output # 返回输出
# 定义 FeedForward 类,实现前馈神经网络
class FeedForward(nn.Module):
def __init__(self, dim: int, hidden_dim: int, multiple_of: int, dropout: float):
super().__init__()
if hidden_dim is None:
hidden_dim = 4 * dim # 设置隐藏层维度
hidden_dim = int(2 * hidden_dim / 3) # 调整隐藏层维度
hidden_dim = multiple_of * ((hidden_dim + multiple_of - 1) // multiple_of) # 调整隐藏层维度
self.w1 = nn.Linear(dim, hidden_dim, bias=False) # 初始化第一层线性变换
self.w2 = nn.Linear(hidden_dim, dim, bias=False) # 初始化第二层线性变换
self.w3 = nn.Linear(dim, hidden_dim, bias=False) # 初始化第三层线性变换
self.dropout = nn.Dropout(dropout) # 初始化 dropout
hidden_dim = 4 * dim
hidden_dim = int(2 * hidden_dim / 3)
hidden_dim = multiple_of * ((hidden_dim + multiple_of - 1) // multiple_of)
self.w1 = nn.Linear(dim, hidden_dim, bias=False)
self.w2 = nn.Linear(hidden_dim, dim, bias=False)
self.w3 = nn.Linear(dim, hidden_dim, bias=False)
self.dropout = nn.Dropout(dropout)
def forward(self, x):
return self.dropout(self.w2(F.silu(self.w1(x)) * self.w3(x))) # 前向传播
return self.dropout(self.w2(F.silu(self.w1(x)) * self.w3(x)))
# 定义 MoEGate 类,实现专家混合(MoE)的门控机制
class MoEGate(nn.Module):
def __init__(self, config: LMConfig):
super().__init__()
self.config = config
self.top_k = config.num_experts_per_tok # 设置每个 token 选择的专家数量
self.n_routed_experts = config.n_routed_experts # 设置路由专家的数量
self.top_k = config.num_experts_per_tok
self.n_routed_experts = config.n_routed_experts
self.scoring_func = config.scoring_func # 设置评分函数
self.alpha = config.aux_loss_alpha # 设置辅助损失的权重
self.seq_aux = config.seq_aux # 设置序列辅助损失
self.scoring_func = config.scoring_func
self.alpha = config.aux_loss_alpha
self.seq_aux = config.seq_aux
self.norm_topk_prob = config.norm_topk_prob # 设置是否归一化 top-k 概率
self.gating_dim = config.dim # 设置门控维度
self.weight = nn.Parameter(torch.empty((self.n_routed_experts, self.gating_dim))) # 初始化权重参数
self.reset_parameters() # 重置参数
self.norm_topk_prob = config.norm_topk_prob
self.gating_dim = config.dim
self.weight = nn.Parameter(torch.empty((self.n_routed_experts, self.gating_dim)))
self.reset_parameters()
def reset_parameters(self) -> None:
import torch.nn.init as init
init.kaiming_uniform_(self.weight, a=math.sqrt(5)) # 使用 Kaiming 初始化权重
init.kaiming_uniform_(self.weight, a=math.sqrt(5))
def forward(self, hidden_states):
bsz, seq_len, h = hidden_states.shape
hidden_states = hidden_states.view(-1, h) # 调整隐藏状态的形状
logits = F.linear(hidden_states, self.weight, None) # 计算 logits
hidden_states = hidden_states.view(-1, h)
logits = F.linear(hidden_states, self.weight, None)
if self.scoring_func == 'softmax':
scores = logits.softmax(dim=-1) # 计算 softmax 评分
scores = logits.softmax(dim=-1)
else:
raise NotImplementedError(f'insupportable scoring function for MoE gating: {self.scoring_func}')
topk_weight, topk_idx = torch.topk(scores, k=self.top_k, dim=-1, sorted=False) # 选择 top-k 专家
topk_weight, topk_idx = torch.topk(scores, k=self.top_k, dim=-1, sorted=False)
if self.top_k > 1 and self.norm_topk_prob:
denominator = topk_weight.sum(dim=-1, keepdim=True) + 1e-20 # 计算归一化分母
topk_weight = topk_weight / denominator # 归一化 top-k 概率
denominator = topk_weight.sum(dim=-1, keepdim=True) + 1e-20
topk_weight = topk_weight / denominator
if self.training and self.alpha > 0.0:
scores_for_aux = scores
@@ -204,9 +204,9 @@ class MoEGate(nn.Module):
aux_loss = (Pi * fi).sum() * self.alpha
else:
aux_loss = None
return topk_idx, topk_weight, aux_loss # 返回 top-k 专家索引、权重和辅助损失
return topk_idx, topk_weight, aux_loss
# 定义 MOEFeedForward 类,实现专家混合(MoE)的前馈神经网络
class MOEFeedForward(nn.Module):
def __init__(self, config: LMConfig):
super().__init__()
@@ -219,16 +219,16 @@ class MOEFeedForward(nn.Module):
dropout=config.dropout,
)
for _ in range(config.n_routed_experts)
]) # 初始化专家列表
])
self.gate = MoEGate(config) # 初始化门控机制
self.gate = MoEGate(config)
if config.n_shared_experts is not None:
self.shared_experts = FeedForward(
dim=config.dim,
hidden_dim=config.hidden_dim,
multiple_of=config.multiple_of,
dropout=config.dropout,
) # 初始化共享专家
)
def forward(self, x):
identity = x
@@ -281,46 +281,35 @@ class MOEFeedForward(nn.Module):
return expert_cache
# 定义 TransformerBlock 类,实现 Transformer 的一个块,包括自注意力和前馈神经网络
class TransformerBlock(nn.Module):
def __init__(self, layer_id: int, args: LMConfig):
super().__init__()
self.n_heads = args.n_heads
self.dim = args.dim
self.head_dim = args.dim // args.n_heads
self.attention = Attention(args) # 初始化自注意力机制
self.attention = Attention(args)
self.layer_id = layer_id
self.attention_norm = RMSNorm(args.dim, eps=args.norm_eps) # 初始化注意力归一化
self.ffn_norm = RMSNorm(args.dim, eps=args.norm_eps) # 初始化前馈神经网络归一化
self.attention_norm = RMSNorm(args.dim, eps=args.norm_eps)
self.ffn_norm = RMSNorm(args.dim, eps=args.norm_eps)
if args.use_moe:
self.feed_forward = MOEFeedForward(args) # 初始化专家混合前馈神经网络
self.feed_forward = MOEFeedForward(args)
else:
self.feed_forward = FeedForward(
dim=args.dim,
hidden_dim=args.hidden_dim,
multiple_of=args.multiple_of,
dropout=args.dropout,
) # 初始化前馈神经网络
)
def forward(self, x, pos_cis, use_kv_cache=False):
h = x + self.attention(self.attention_norm(x), pos_cis, use_kv_cache) # 计算自注意力
out = h + self.feed_forward(self.ffn_norm(h)) # 计算前馈神经网络
return out # 返回输出
h = x + self.attention(self.attention_norm(x), pos_cis, use_kv_cache)
out = h + self.feed_forward(self.ffn_norm(h))
return out
# 定义 Transformer 类,实现整个 Transformer 模型
class Transformer(PreTrainedModel):
config_class = LMConfig
last_loss: Optional[torch.Tensor]
def __init__(self, params: LMConfig = None):
super().__init__(params)
if not params:
params = LMConfig()
self.params = params
self.vocab_size = params.vocab_size
self.n_layers = params.n_layers
class Transformer(PreTrainedModel):
config_class = LMConfig
last_loss: Optional[torch.Tensor]
@@ -333,99 +322,99 @@ class Transformer(PreTrainedModel):
self.vocab_size = params.vocab_size
self.n_layers = params.n_layers
self.tok_embeddings = nn.Embedding(params.vocab_size, params.dim) # 初始化词嵌入层
self.dropout = nn.Dropout(params.dropout) # 初始化 dropout 层
self.layers = torch.nn.ModuleList() # 初始化 Transformer 块列表
self.tok_embeddings = nn.Embedding(params.vocab_size, params.dim)
self.dropout = nn.Dropout(params.dropout)
self.layers = torch.nn.ModuleList()
for layer_id in range(self.n_layers):
self.layers.append(TransformerBlock(layer_id, params)) # 添加 Transformer 块
self.norm = RMSNorm(params.dim, eps=params.norm_eps) # 初始化归一化层
self.output = nn.Linear(params.dim, params.vocab_size, bias=False) # 初始化输出层
self.tok_embeddings.weight = self.output.weight # 共享词嵌入和输出层的权重
pos_cis = precompute_pos_cis(self.params.dim // self.params.n_heads, self.params.max_seq_len) # 预计算位置编码
self.register_buffer("pos_cis", pos_cis, persistent=False) # 注册位置编码缓冲区
self.layers.append(TransformerBlock(layer_id, params))
self.norm = RMSNorm(params.dim, eps=params.norm_eps)
self.output = nn.Linear(params.dim, params.vocab_size, bias=False)
self.tok_embeddings.weight = self.output.weight
pos_cis = precompute_pos_cis(self.params.dim // self.params.n_heads, self.params.max_seq_len)
self.register_buffer("pos_cis", pos_cis, persistent=False)
self.apply(self._init_weights) # 初始化模型权重
self.apply(self._init_weights)
for pn, p in self.named_parameters():
if pn.endswith('w3.weight') or pn.endswith('wo.weight'):
torch.nn.init.normal_(p, mean=0.0, std=0.02 / math.sqrt(2 * params.n_layers)) # 对特定权重进行初始化
torch.nn.init.normal_(p, mean=0.0, std=0.02 / math.sqrt(2 * params.n_layers))
self.last_loss = None # 初始化最后一个损失
self.OUT = CausalLMOutputWithPast() # 初始化输出对象
self.last_loss = None
self.OUT = CausalLMOutputWithPast()
def _init_weights(self, module):
if isinstance(module, nn.Linear):
torch.nn.init.normal_(module.weight, mean=0.0, std=0.02) # 初始化线性层的权重
torch.nn.init.normal_(module.weight, mean=0.0, std=0.02)
if module.bias is not None:
torch.nn.init.zeros_(module.bias) # 初始化线性层的偏置
torch.nn.init.zeros_(module.bias)
elif isinstance(module, nn.Embedding):
torch.nn.init.normal_(module.weight, mean=0.0, std=0.02) # 初始化嵌入层的权重
torch.nn.init.normal_(module.weight, mean=0.0, std=0.02)
def forward(self, tokens: Optional[torch.Tensor] = None, targets: Optional[torch.Tensor] = None,
use_kv_cache=False, **keyargs):
if 'input_ids' in keyargs:
tokens = keyargs['input_ids'] # 如果传入了 input_ids,则使用 input_ids
tokens = keyargs['input_ids']
if 'attention_mask' in keyargs:
targets = keyargs['attention_mask'] # 如果传入了 attention_mask,则使用 attention_mask
targets = keyargs['attention_mask']
_bsz, seqlen = tokens.shape # 获取批量大小和序列长度
h = self.tok_embeddings(tokens) # 获取词嵌入
h = self.dropout(h) # 应用 dropout
pos_cis = self.pos_cis[:seqlen] # 获取对应序列长度的位置编码
_bsz, seqlen = tokens.shape
h = self.tok_embeddings(tokens)
h = self.dropout(h)
pos_cis = self.pos_cis[:seqlen]
for idx, layer in enumerate(self.layers):
h = layer(h, pos_cis, use_kv_cache) # 逐层应用 Transformer 块
h = layer(h, pos_cis, use_kv_cache)
h = self.norm(h) # 应用归一化
h = self.norm(h)
if targets is not None:
logits = self.output(h) # 计算 logits
self.last_loss = F.cross_entropy(logits.view(-1, logits.size(-1)), targets.view(-1), ignore_index=-1) # 计算交叉熵损失
logits = self.output(h)
self.last_loss = F.cross_entropy(logits.view(-1, logits.size(-1)), targets.view(-1), ignore_index=-1)
else:
logits = self.output(h[:, [-1], :]) # 计算最后一个 token 的 logits
self.last_loss = None # 没有目标时,损失为 None
logits = self.output(h[:, [-1], :])
self.last_loss = None
self.OUT.__setitem__('logits', logits) # 设置输出对象的 logits
self.OUT.__setitem__('last_loss', self.last_loss) # 设置输出对象的 last_loss
self.OUT.__setitem__('logits', logits)
self.OUT.__setitem__('last_loss', self.last_loss)
return self.OUT # 返回输出对象
return self.OUT
@torch.inference_mode() # 推理模式
@torch.inference_mode()
def generate(self, idx, eos, max_new_tokens, temperature=0.7, top_k=None, stream=True, repetition_penalty=1.,
use_kv_cache=True):
index = idx.shape[1] # 获取当前序列长度
while idx.shape[1] < max_new_tokens - 1: # 当生成的 token 数量小于最大数量时
inference_res = self(idx, use_kv_cache=use_kv_cache) # 进行前向传播
logits = inference_res.logits # 获取 logits
logits = logits[:, -1, :] # 获取最后一个 token 的 logits
index = idx.shape[1]
while idx.shape[1] < max_new_tokens - 1:
inference_res = self(idx, use_kv_cache=use_kv_cache)
logits = inference_res.logits
logits = logits[:, -1, :]
for token in set(idx.tolist()[0]): # 对重复 token 进行惩罚
for token in set(idx.tolist()[0]):
logits[:, token] /= repetition_penalty
if temperature == 0.0: # 如果温度为 0,直接选择概率最高的 token
if temperature == 0.0:
_, idx_next = torch.topk(logits, k=1, dim=-1)
else:
logits = logits / temperature # 调整 logits
if top_k is not None: # 如果设置了 top-k 采样
logits = logits / temperature
if top_k is not None:
v, _ = torch.topk(logits, min(top_k, logits.size(-1)))
logits[logits < v[:, [-1]]] = -float('Inf') # 将小于 top-k 的 logits 设为负无穷
logits[logits < v[:, [-1]]] = -float('Inf')
probs = F.softmax(logits, dim=-1) # 计算概率
idx_next = torch.multinomial(probs, num_samples=1, generator=None) # 采样下一个 token
probs = F.softmax(logits, dim=-1)
idx_next = torch.multinomial(probs, num_samples=1, generator=None)
if idx_next == eos: # 如果生成的 token 是结束符,停止生成
if idx_next == eos:
break
idx = torch.cat((idx, idx_next), dim=1) # 将生成的 token 添加到序列中
if stream: # 如果需要流式输出
yield idx[:, index:] # 返回生成的 token
idx = torch.cat((idx, idx_next), dim=1)
if stream:
yield idx[:, index:]
if not stream: # 如果不需要流式输出
yield idx[:, index:] # 返回生成的 token
if not stream:
yield idx[:, index:]
@torch.inference_mode() # 推理模式
@torch.inference_mode()
def eval_answer(self, idx):
idx_cond = idx if idx.size(1) <= self.params.max_seq_len else idx[:, -self.params.max_seq_len:] # 截取序列
inference_res = self(idx_cond) # 进行前向传播
logits = inference_res.logits # 获取 logits
logits = logits[:, -1, :] # 获取最后一个 token 的 logits
return logits # 返回 logits
idx_cond = idx if idx.size(1) <= self.params.max_seq_len else idx[:, -self.params.max_seq_len:]
inference_res = self(idx_cond)
logits = inference_res.logits
logits = logits[:, -1, :]
return logits