mirror of
https://github.com/datawhalechina/llms-from-scratch-cn.git
synced 2026-02-20 01:34:46 +08:00
319 lines
11 KiB
Python
319 lines
11 KiB
Python
########################################################################################################
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# The RWKV Language Model - https://github.com/BlinkDL/RWKV-LM
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########################################################################################################
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import types
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import copy
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import torch
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import math
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from torch.nn import functional as F
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import torch.nn as nn
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RWKV_K_CLAMP = 60
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RWKV_K_EPS = 1e-8
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RWKV_HEAD_QK_DIM = 256
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print(f'\nRWKV_K_CLAMP {RWKV_K_CLAMP} RWKV_K_EPS {RWKV_K_EPS} RWKV_HEAD_QK_DIM {RWKV_HEAD_QK_DIM}\n')
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DEBUG_TIME = False # True False - show trained time-coeffs
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############################################################################################################
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RWKV_CFG = types.SimpleNamespace()
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class RWKV_ChannelMix(nn.Module):
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def __init__(self, layer_id):
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super().__init__()
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self.layer_id = layer_id
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self.time_shift = nn.ZeroPad2d((0,0,1,-1))
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self.time_mix_k = nn.Parameter(torch.ones(1, 1, RWKV_CFG.n_embd))
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self.time_mix_r = nn.Parameter(torch.ones(1, 1, RWKV_CFG.n_embd))
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hidden_sz = 4 * RWKV_CFG.n_embd
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self.key = nn.Linear(RWKV_CFG.n_embd, hidden_sz, bias=False)
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self.receptance = nn.Linear(RWKV_CFG.n_embd, RWKV_CFG.n_embd, bias=False)
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self.value = nn.Linear(hidden_sz, RWKV_CFG.n_embd, bias=False)
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def forward(self, x):
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xx = self.time_shift(x)
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xk = x * self.time_mix_k + xx * (1 - self.time_mix_k)
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xr = x * self.time_mix_r + xx * (1 - self.time_mix_r)
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k = self.key(xk)
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k = torch.square(torch.relu(k))
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kv = self.value(k)
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rkv = torch.sigmoid(self.receptance(xr)) * kv
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return rkv
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class RWKV_TimeMix(nn.Module):
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def __init__(self, layer_id):
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super().__init__()
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self.layer_id = layer_id
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self.time_decay = nn.Parameter(torch.ones(RWKV_CFG.n_embd, 1))
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self.time_curve = torch.tensor([-(RWKV_CFG.ctx_len - 2 - i) for i in range(RWKV_CFG.ctx_len-1)]).unsqueeze(0)
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self.time_first = nn.Parameter(torch.ones(RWKV_CFG.n_embd, 1) * math.log(0.3))
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self.time_shift = nn.ZeroPad2d((0,0,1,-1))
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self.time_mix_k = nn.Parameter(torch.ones(1,1,RWKV_CFG.n_embd))
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self.time_mix_v = nn.Parameter(torch.ones(1,1,RWKV_CFG.n_embd))
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self.time_mix_r = nn.Parameter(torch.ones(1,1,RWKV_CFG.n_embd))
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self.key = nn.Linear(RWKV_CFG.n_embd, RWKV_CFG.n_embd, bias=False)
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self.value = nn.Linear(RWKV_CFG.n_embd, RWKV_CFG.n_embd, bias=False)
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self.receptance = nn.Linear(RWKV_CFG.n_embd, RWKV_CFG.n_embd, bias=False)
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self.output = nn.Linear(RWKV_CFG.n_embd, RWKV_CFG.n_embd, bias=False)
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def forward(self, x):
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B, T, C = x.size()
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xx = self.time_shift(x)
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xk = x * self.time_mix_k + xx * (1 - self.time_mix_k)
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xv = x * self.time_mix_v + xx * (1 - self.time_mix_v)
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xr = x * self.time_mix_r + xx * (1 - self.time_mix_r)
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k = self.key(xk).transpose(-1, -2)
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v = self.value(xv).transpose(-1, -2)
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r = self.receptance(xr)
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k = torch.clamp(k, max=RWKV_K_CLAMP)
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k = torch.exp(k)
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kv = k * v
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self.time_w = torch.cat([torch.exp(self.time_decay) * self.time_curve.to(self.time_decay.device), self.time_first], dim=-1)
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w = torch.exp(self.time_w)
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w = w[:,-T:].unsqueeze(1)
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wkv = F.conv1d(nn.ZeroPad2d((T-1, 0, 0, 0))(kv), w, groups=C)
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wk = F.conv1d(nn.ZeroPad2d((T-1, 0, 0, 0))(k), w, groups=C) + RWKV_K_EPS
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rwkv = torch.sigmoid(r) * (wkv / wk).transpose(-1, -2)
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rwkv = self.output(rwkv)
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return rwkv
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class Block(nn.Module):
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def __init__(self, layer_id):
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super().__init__()
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self.layer_id = layer_id
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self.ln1 = nn.LayerNorm(RWKV_CFG.n_embd)
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self.ln2 = nn.LayerNorm(RWKV_CFG.n_embd)
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if self.layer_id == 0:
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self.ln0 = nn.LayerNorm(RWKV_CFG.n_embd)
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if self.layer_id == 0 and RWKV_CFG.model_type == 'RWKV-ffnPre':
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self.ffnPre = RWKV_ChannelMix(layer_id+1000)
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else:
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self.att = RWKV_TimeMix(layer_id)
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self.ffn = RWKV_ChannelMix(layer_id)
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def forward(self, x):
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if self.layer_id == 0:
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x = self.ln0(x)
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if self.layer_id == 0 and RWKV_CFG.model_type == 'RWKV-ffnPre':
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x = x + self.ffnPre(self.ln1(x))
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else:
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x = x + self.att(self.ln1(x))
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x = x + self.ffn(self.ln2(x))
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return x
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class RWKV_GPT(nn.Module):
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def __init__(self, MODEL_NAME, RUN_DEVICE, model_type, vocab_size, n_layer, n_embd, ctx_len):
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global RWKV_CFG
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super().__init__()
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RWKV_CFG.RUN_DEVICE = RUN_DEVICE
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RWKV_CFG.model_type = model_type
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RWKV_CFG.vocab_size = vocab_size
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RWKV_CFG.n_layer = n_layer
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RWKV_CFG.n_embd = n_embd
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RWKV_CFG.ctx_len = ctx_len
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print('\nloading RWKV-GPT', MODEL_NAME)
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self.emb = nn.Embedding(vocab_size, n_embd)
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self.blocks = nn.Sequential(*[Block(i) for i in range(n_layer)])
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self.ln_out = nn.LayerNorm(n_embd)
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self.head = nn.Linear(n_embd, vocab_size, bias=False)
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if RWKV_HEAD_QK_DIM > 0:
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self.head_q = nn.Linear(n_embd, RWKV_HEAD_QK_DIM, bias=False)
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self.head_q.scale_init = 0
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self.head_k = nn.Linear(n_embd, RWKV_HEAD_QK_DIM, bias=False)
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self.head_k.scale_init = 0.1
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self.register_buffer("copy_mask", torch.tril(
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torch.ones(ctx_len, ctx_len)))
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self.ctx_len = ctx_len
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self.eval()
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self.load_state_dict(torch.load(MODEL_NAME + '.pth'))
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self.eval()
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def forward(self, idx):
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B, T = idx.size()
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assert T <= self.ctx_len, "Cannot forward, because len(input) > model ctx_len."
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x = self.emb(idx)
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x = self.blocks(x)
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x = self.ln_out(x)
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if RWKV_HEAD_QK_DIM > 0:
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q = self.head_q(x)[:, :T, :]
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k = self.head_k(x)[:, :T, :]
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c = (q @ k.transpose(-2, -1)) * (1.0 / RWKV_HEAD_QK_DIM)
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c = c.masked_fill(self.copy_mask[:T, :T] == 0, 0)
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c = c @ F.one_hot(idx, num_classes=RWKV_CFG.vocab_size).float()
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x = self.head(x) + c
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else:
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x = self.head(x)
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return x
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############################################################################################################
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class RWKV_RNN():
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def __init__(self, MODEL_NAME, RUN_DEVICE, model_type, n_layer, n_embd, ctx_len):
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self.RUN_DEVICE = RUN_DEVICE
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self.model_type = model_type
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self.n_layer = n_layer
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self.n_embd = n_embd
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self.ctx_len = ctx_len
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self.w = types.SimpleNamespace()
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w = torch.load(MODEL_NAME + '.pth',
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map_location=torch.device(RUN_DEVICE))
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for x in w.keys():
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if '.time_' in x:
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w[x] = w[x].squeeze()
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if '.time_decay' in x:
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w[x] = torch.exp(-torch.exp(w[x]))
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if '.time_first' in x:
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w[x] = torch.exp(w[x])
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if DEBUG_TIME and '.time_' in x:
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print(x, w[x].squeeze().cpu().numpy())
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xx = x.split('.')
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here = self.w
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for i in range(len(xx)):
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if xx[i].isdigit():
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ii = int(xx[i])
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if ii not in here:
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here[ii] = types.SimpleNamespace()
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here = here[ii]
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else:
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if i == len(xx) - 1:
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setattr(here, xx[i], w[x])
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elif not hasattr(here, xx[i]):
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if xx[i+1].isdigit():
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setattr(here, xx[i], {})
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else:
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setattr(here, xx[i], types.SimpleNamespace())
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here = getattr(here, xx[i])
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self.clear()
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def clear(self):
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self.xx = {}
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self.aa = {}
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self.bb = {}
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self.hk = None
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def save(self, target):
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target.xx = copy.deepcopy(self.xx)
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target.aa = copy.deepcopy(self.aa)
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target.bb = copy.deepcopy(self.bb)
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target.hk = copy.deepcopy(self.hk)
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def load(self, target):
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self.xx = copy.deepcopy(target.xx)
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self.aa = copy.deepcopy(target.aa)
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self.bb = copy.deepcopy(target.bb)
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self.hk = copy.deepcopy(target.hk)
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def LN(self, xx, w):
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return F.layer_norm(xx, (self.n_embd,), weight=w.weight, bias=w.bias)
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def FF(self, xx, w, name):
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if name not in self.xx:
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self.xx[name] = torch.zeros(self.n_embd, device=self.RUN_DEVICE)
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xk = xx * w.time_mix_k + self.xx[name] * (1 - w.time_mix_k)
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xr = xx * w.time_mix_r + self.xx[name] * (1 - w.time_mix_r)
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self.xx[name] = xx
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r = torch.sigmoid(w.receptance.weight @ xr)
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k = torch.square(torch.relu(w.key.weight @ xk))
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kv = w.value.weight @ k
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return r * kv
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def SA(self, xx, w, name):
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if name not in self.xx:
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self.xx[name] = torch.zeros(self.n_embd, device=self.RUN_DEVICE)
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self.aa[name] = torch.zeros(self.n_embd, device=self.RUN_DEVICE)
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self.bb[name] = torch.zeros(self.n_embd, device=self.RUN_DEVICE)
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xk = xx * w.time_mix_k + self.xx[name] * (1 - w.time_mix_k)
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xv = xx * w.time_mix_v + self.xx[name] * (1 - w.time_mix_v)
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xr = xx * w.time_mix_r + self.xx[name] * (1 - w.time_mix_r)
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self.xx[name] = xx
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r = torch.sigmoid(w.receptance.weight @ xr)
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k = torch.exp(torch.clamp(w.key.weight @ xk, max=RWKV_K_CLAMP))
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v = w.value.weight @ xv
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kv = k * v
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a = self.aa[name] + w.time_first * kv
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b = self.bb[name] + w.time_first * k
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self.aa[name] = w.time_decay * self.aa[name] + kv
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self.bb[name] = w.time_decay * self.bb[name] + k
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rwkv = r * a / (b + RWKV_K_EPS)
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return w.output.weight @ rwkv
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def run(self, ctx):
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w = self.w
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x = w.emb.weight[ctx[-1]]
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for i in range(self.n_layer):
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if i == 0:
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x = self.LN(x, w.blocks[i].ln0)
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if i == 0 and self.model_type == 'RWKV-ffnPre':
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x = x + self.FF(self.LN(x, w.blocks[i].ln1), w.blocks[i].ffnPre, f'ffnPre.{i}')
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else:
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x = x + self.SA(self.LN(x, w.blocks[i].ln1), w.blocks[i].att, f'att.{i}')
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x = x + self.FF(self.LN(x, w.blocks[i].ln2), w.blocks[i].ffn, f'ffn.{i}')
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x = self.LN(x, w.ln_out)
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if RWKV_HEAD_QK_DIM > 0:
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if self.hk == None:
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self.hk = (w.head_k.weight @ x).unsqueeze(0)
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else:
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self.hk = torch.cat(
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[self.hk, (w.head_k.weight @ x).unsqueeze(0)], dim=0)
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if self.hk.shape[0] > self.ctx_len:
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self.hk = self.hk[-self.ctx_len:, :]
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q = w.head_q.weight @ x
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x = w.head.weight @ x
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x = x.cpu().numpy().tolist()
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c = (self.hk @ q) / RWKV_HEAD_QK_DIM
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for i in range(len(c)):
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x[ctx[i]] += c[i]
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else:
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x = w.head.weight @ x
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x = x.cpu().numpy().tolist()
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return x |