BERT-pytorch源码实现，解决内存溢出问题

BERT-pytorch源码实现，解决内存溢出问题

相信大家很多人都在做BERT这个模型，但是，有些人可能就是直接从transfermer这个模型里直接导入数据，但是这种方法不方便我们修改模型，于是有些人就通过pytorch详细实现了BERT,但是博主发现，这些详细实现BERT的代码出现了内存溢出问题，博主就做了改进，下面代码，我们可以解决掉内存溢出问题，主要还是因为中间结果并没有完全释放，代码如下：
注：大家如果要解决内存溢出问题，关注del语句就可以了。

'''
  code by Tae Hwan Jung(Jeff Jung) @graykode, modify by wmathor
  Reference : https://github.com/jadore801120/attention-is-all-you-need-pytorch
         https://github.com/JayParks/transformer, https://github.com/dhlee347/pytorchic-bert
'''
import re
import math
import torch
import numpy as np
from random import *
import torch.nn as nn
import torch.optim as optim
import torch.utils.data as Data
 
import matplotlib.pyplot as plt
from data_process import get_data

setences,label,setences_test,label_test=get_data()
device = torch.device('cpu')

sentences=setences
#text = (
#    'Hello, how are you? I am Romeo.\n' # R
#    'Hello, Romeo My name is Juliet. Nice to meet you.\n' # J
#    'Nice meet you too. How are you today?\n' # R
#    'Great. My baseball team won the competition.\n' # J
#    'Oh Congratulations, Juliet\n' # R
#    'Thank you Romeo\n' # J
#    'Where are you going today?\n' # R
#    'I am going shopping. What about you?\n' # J
#    'I am going to visit my grandmother. she is not very well' # R
#)
#sentences = re.sub("[.,!?\\-]", '', text.lower()).split('\n') # filt
#print(sentences)

word_list = list(set(" ".join(setences).split())|set(" ".join(setences_test).split())) # ['hello', 'how', 'are', 'you',...]
word2idx = {'[PAD]' : 0, '[CLS]' : 1, '[SEP]' : 2, '[MASK]' : 3}
for i, w in enumerate(word_list):
    word2idx[w] = i + 4
idx2word = {i: w for i, w in enumerate(word2idx)}
vocab_size = len(word2idx)
 
token_list = list()
for sentence in setences:
    arr = [word2idx[s] for s in sentence.split()]
    token_list.append(arr)







#print(token_list)
'''
[[12, 7, 22, 5, 39, 21, 15],
 [12, 15, 13, 35, 10, 27, 34, 14, 19, 5],
 [34, 19, 5, 17, 7, 22, 5, 8],
 [33, 13, 37, 32, 28, 11, 16],
 [30, 23, 27],
 [6, 5, 15],
 [36, 22, 5, 31, 8],
 [39, 21, 31, 18, 9, 20, 5],
 [39, 21, 31, 14, 29, 13, 4, 25, 10, 26, 38, 24]]
'''
# BERT Parameters
maxlen = 30
batch_size = 6
max_pred = 5 # max tokens of prediction
n_layers = 6
n_heads = 12
d_model = 768
d_ff = 768*4 # 4*d_model, FeedForward dimension
d_k = d_v = 64  # dimension of K(=Q), V
n_segments = 3
# sample IsNext and NotNext to be same in small batch size
def make_data():
    batch = []
    for i in range(len(setences)):
        tokens_a_index =  i
        tokens_a = token_list[tokens_a_index]
        input_ids = [word2idx['[CLS]']] + tokens_a + [word2idx['[SEP]']]
        segment_ids = [0] * (1 + len(tokens_a) + 1) 
 
        # MASK LM
        n_pred = min(max_pred, max(1, int(len(input_ids) * 0.15)))  # 15 % of tokens in one sentence
        cand_maked_pos = [i for i, token in enumerate(input_ids)
                          if token != word2idx['[CLS]'] and token != word2idx['[SEP]']]  # candidate masked position
        shuffle(cand_maked_pos)

        masked_tokens, masked_pos = [], []
        for pos in cand_maked_pos[:n_pred]:
            masked_pos.append(pos)
            masked_tokens.append(input_ids[pos])
            if random() < 0.8:  # 80%
                input_ids[pos] = word2idx['[MASK]']  # make mask
            elif random() > 0.9:  # 10%
                index = randint(0, vocab_size - 1)  # random index in vocabulary
                while index < 4:  # can't involve 'CLS', 'SEP', 'PAD'
                    index = randint(0, vocab_size - 1)
                input_ids[pos] = index  # replace
 
        # Zero Paddings
        n_pad = maxlen - len(input_ids)
        input_ids.extend([0] * n_pad)
        segment_ids.extend([0] * n_pad)
 
        # Zero Padding (100% - 15%) tokens
        if max_pred > n_pred:
            n_pad = max_pred - n_pred
            masked_tokens.extend([0] * n_pad)
            masked_pos.extend([0] * n_pad)
 
       
        batch.append([input_ids, segment_ids, masked_tokens, masked_pos, label[tokens_a_index]])  # IsNext
    return batch
batch = make_data()
input_ids, segment_ids, masked_tokens, masked_pos, isNext = zip(*batch)
'''>>> a = [1,2,3]
b = [4,5,6]
zipped = zip(a,b)     # 打包为元组的列表
[(1, 4), (2, 5), (3, 6)]
zip(*zipped)          # 与 zip 相反，可理解为解压，为zip的逆过程，可用于矩阵的转置
[(1, 2, 3), (4, 5, 6)]
'''
input_ids, segment_ids, masked_tokens, masked_pos, isNext = \
    torch.LongTensor(input_ids), torch.LongTensor(segment_ids), torch.LongTensor(masked_tokens), \
    torch.LongTensor(masked_pos), torch.LongTensor(isNext)
 
 
class MyDataSet(Data.Dataset):
    def __init__(self, input_ids, segment_ids, masked_tokens, masked_pos, isNext):
        self.input_ids = input_ids
        self.segment_ids = segment_ids
        self.masked_tokens = masked_tokens
        self.masked_pos = masked_pos
        self.isNext = isNext
 
    def __len__(self):
        return len(self.input_ids)
 
    def __getitem__(self, idx):
        return self.input_ids[idx], self.segment_ids[idx], self.masked_tokens[idx], self.masked_pos[idx], self.isNext[
            idx]
 
loader = Data.DataLoader(MyDataSet(input_ids, segment_ids, masked_tokens, masked_pos, isNext), batch_size, True)
def get_attn_pad_mask(seq_q, seq_k):
    batch_size, seq_len = seq_q.size()   #[batch_size,maxlen]
    # eq(zero) is PAD token
    pad_attn_mask = seq_q.data.eq(0).unsqueeze(1)  # [batch_size, 1, seq_len]
    return pad_attn_mask.expand(batch_size, seq_len, seq_len)  # [batch_size, seq_len, seq_len]
 
def gelu(x):
    return x * 0.5 * (1.0 + torch.erf(x / math.sqrt(2.0)))
 
class Embedding(nn.Module):
    def __init__(self):
        super(Embedding, self).__init__()
        self.tok_embed = nn.Embedding(vocab_size, d_model)  # token embedding
        self.pos_embed = nn.Embedding(maxlen, d_model)  # position embedding
        self.seg_embed = nn.Embedding(n_segments, d_model)  # segment(token type) embedding
        self.norm = nn.LayerNorm(d_model)
 
    def forward(self, x, seg):
        seq_len = x.size(1)
        pos = torch.arange(seq_len, dtype=torch.long)
        # print("pos:",pos)
        '''pos: tensor([ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17,
        18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29])'''
        pos = pos.unsqueeze(0).expand_as(x).to(device)  # [seq_len] -> [batch_size, seq_len]
        # print("pos_batch:", pos)
        embedding = self.tok_embed(x) + self.pos_embed(pos) + self.seg_embed(seg)
        del pos,x, seg
        return self.norm(embedding)
 
class ScaledDotProductAttention(nn.Module):
    def __init__(self):
        super(ScaledDotProductAttention, self).__init__()
 
    def forward(self, Q, K, V, attn_mask):
        scores = torch.matmul(Q, K.transpose(-1, -2)) / np.sqrt(d_k) # scores : [batch_size, n_heads, seq_len, seq_len]
        scores.masked_fill_(attn_mask, -1e9) # Fills elements of self tensor with value where mask is one.
        attn = nn.Softmax(dim=-1)(scores)
        context = torch.matmul(attn, V)
        del attn,scores,Q, K, V,attn_mask
        return context
 
class MultiHeadAttention(nn.Module):
    def __init__(self):
        super(MultiHeadAttention, self).__init__()
        self.W_Q = nn.Linear(d_model, d_k * n_heads)
        self.W_K = nn.Linear(d_model, d_k * n_heads)
        self.W_V = nn.Linear(d_model, d_v * n_heads)
    def forward(self, Q, K, V, attn_mask):
        # q: [batch_size, seq_len, d_model], k: [batch_size, seq_len, d_model], v: [batch_size, seq_len, d_model]
        residual, batch_size = Q, Q.size(0)
        residual=residual.to(device)
       
        # (B, S, D) -proj-> (B, S, D) -split-> (B, S, H, W) -trans-> (B, H, S, W)
        q_s = self.W_Q(Q).view(batch_size, -1, n_heads, d_k).transpose(1,2)  # q_s: [batch_size, n_heads, seq_len, d_k]
        k_s = self.W_K(K).view(batch_size, -1, n_heads, d_k).transpose(1,2)  # k_s: [batch_size, n_heads, seq_len, d_k]
        v_s = self.W_V(V).view(batch_size, -1, n_heads, d_v).transpose(1,2)  # v_s: [batch_size, n_heads, seq_len, d_v]
 
        attn_mask = attn_mask.unsqueeze(1).repeat(1, n_heads, 1, 1) # attn_mask : [batch_size, n_heads, seq_len, seq_len]
 
        # context: [batch_size, n_heads, seq_len, d_v], attn: [batch_size, n_heads, seq_len, seq_len]
        context = ScaledDotProductAttention()(q_s, k_s, v_s, attn_mask)
        context = context.transpose(1, 2).contiguous().view(batch_size, -1, n_heads * d_v)# context: [batch_size, seq_len, n_heads, d_v]
        output = nn.Linear(n_heads * d_v, d_model).to(device)(context)
        del context,attn_mask,q_s,k_s,v_s
        
        return nn.LayerNorm(d_model).to(device)(output + residual) # output: [batch_size, seq_len, d_model]
 
class PoswiseFeedForwardNet(nn.Module):
    def __init__(self):
        super(PoswiseFeedForwardNet, self).__init__()
        self.fc1 = nn.Linear(d_model, d_ff)
        self.fc2 = nn.Linear(d_ff, d_model)
 
    def forward(self, x):
        # (batch_size, seq_len, d_model) -> (batch_size, seq_len, d_ff) -> (batch_size, seq_len, d_model)
       
        return self.fc2(gelu(self.fc1(x)))
 
class EncoderLayer(nn.Module):
    def __init__(self):
        super(EncoderLayer, self).__init__()
        self.enc_self_attn = MultiHeadAttention()
        self.pos_ffn = PoswiseFeedForwardNet()
 
    def forward(self, enc_inputs, enc_self_attn_mask):
        enc_outputs = self.enc_self_attn(enc_inputs, enc_inputs, enc_inputs, enc_self_attn_mask) # enc_inputs to same Q,K,V
        enc_outputs = self.pos_ffn(enc_outputs) # enc_outputs: [batch_size, seq_len, d_model]
        del enc_self_attn_mask,enc_inputs
        return enc_outputs

class BERT(nn.Module):
    def __init__(self):
        super(BERT, self).__init__()
        self.embedding = Embedding()
        self.layers = nn.ModuleList([EncoderLayer() for _ in range(n_layers)])
        self.fc = nn.Sequential(
            nn.Linear(d_model, d_model),
            nn.Dropout(0.5),
            nn.Tanh(),
        )
        self.classifier = nn.Linear(d_model, 3)
        self.linear = nn.Linear(d_model, d_model)
        self.activ2 = gelu
        # fc2 is shared with embedding layer
        embed_weight = self.embedding.tok_embed.weight
        self.fc2 = nn.Linear(d_model, vocab_size, bias=False)
        self.fc2.weight = embed_weight
 
    def forward(self, input_ids, segment_ids, masked_pos):
        output = self.embedding(input_ids, segment_ids) # [bach_size, seq_len, d_model]
        enc_self_attn_mask = get_attn_pad_mask(input_ids, input_ids) # [batch_size, maxlen, maxlen]
        for layer in self.layers:
            # output: [batch_size, max_len, d_model]
            output = layer(output, enc_self_attn_mask)
        # it will be decided by first token(CLS)
        '''
         (fc): Sequential(
            (0): Linear(in_features=768, out_features=768, bias=True)
            (1): Dropout(p=0.5, inplace=False)
            (2): Tanh()
            )
          (classifier): Linear(in_features=768, out_features=2, bias=True)
          (linear): Linear(in_features=768, out_features=768, bias=True)
          (fc2): Linear(in_features=768, out_features=40, bias=False)
        '''
        # logits_clsf :根据[CLS]预测是否是连续的句子,[CLS]在第一维
        h_pooled = self.fc(output[:, 0]) # [batch_size, d_model]
        logits_clsf = self.classifier(h_pooled) # [batch_size, 2] predict isNext
 
        masked_pos = masked_pos[:, :, None].expand(-1, -1, d_model) # [batch_size, max_pred, d_model]
        h_masked = torch.gather(output, 1, masked_pos) # masking position [batch_size, max_pred, d_model]
        h_masked = self.activ2(self.linear(h_masked)) # [batch_size, max_pred, d_model]
        #logits_lm：预测mask的token
        logits_lm = self.fc2(h_masked) # [batch_size, max_pred, vocab_size]
        del h_masked,h_pooled,output,enc_self_attn_mask,masked_pos,input_ids,segment_ids
        return logits_lm, logits_clsf
model = BERT().to(device)
# print(model)
criterion = nn.CrossEntropyLoss()
optimizer = optim.Adam(model.parameters(), lr=0.000001)
#out = torch.gather(input, dim, index)
index = torch.from_numpy(np.array([[1, 2, 0], [2, 0, 1]])).type(torch.LongTensor)
index = index[:, :, None].expand(-1, -1, 10)
loss_list=[]
for epoch in range(10):
    loss_sum=0
    for input_ids, segment_ids, masked_tokens, masked_pos, isNext in loader:
   
      
      logits_lm, logits_clsf = model(input_ids, segment_ids, masked_pos)
      #logits_lm:[batch_size,max_pred,vocab_size] -> [batch_size*max_pred,vocab_size],batch_size*max_pred个词。每个词都有vocab_size种可能。
      loss_lm = criterion(logits_lm.view(-1, vocab_size), masked_tokens.view(-1)) # for masked LM
      loss_lm = (loss_lm.float()).mean()
    #  isNext=isNext.to(device)
      loss_clsf = criterion(logits_clsf, isNext) # for sentence classification
      loss = loss_lm + loss_clsf
      loss_sum=loss_sum+loss
      loss_list.append(float(loss))

      print('Epoch:', '%04d' % (epoch + 1), 'loss =', '{:.6f}'.format(loss))
      optimizer.zero_grad()
      loss.backward()
      optimizer.step()
      del loss, logits_clsf, input_ids,segment_ids,masked_tokens,masked_pos,logits_lm,isNext,loss_clsf,loss_lm
     
    

# Predict mask tokens ans isNext



print('test')

token_list=[]

for sentence in setences_test:
    arr = [word2idx[s] for s in sentence.split()]
    token_list.append(arr)


def make_data_test():
    batch = []
  
    for i in range(len(setences_test)):
        tokens_a_index =  i
        tokens_a = token_list[tokens_a_index]
        input_ids = [word2idx['[CLS]']] + tokens_a + [word2idx['[SEP]']]
        segment_ids = [0] * (1 + len(tokens_a) + 1) 
 
        # MASK LM
        n_pred = min(max_pred, max(1, int(len(input_ids) * 0.15)))  # 15 % of tokens in one sentence
        cand_maked_pos = [i for i, token in enumerate(input_ids)
                          if token != word2idx['[CLS]'] and token != word2idx['[SEP]']]  # candidate masked position
        shuffle(cand_maked_pos)

        masked_tokens, masked_pos = [], []
        for pos in cand_maked_pos[:n_pred]:
            masked_pos.append(pos)
            masked_tokens.append(input_ids[pos])
            if random() < 0.8:  # 80%
                input_ids[pos] = word2idx['[MASK]']  # make mask
            elif random() > 0.9:  # 10%
                index = randint(0, vocab_size - 1)  # random index in vocabulary
                while index < 4:  # can't involve 'CLS', 'SEP', 'PAD'
                    index = randint(0, vocab_size - 1)
                input_ids[pos] = index  # replace
 
        # Zero Paddings
        n_pad = maxlen - len(input_ids)
        input_ids.extend([0] * n_pad)
        segment_ids.extend([0] * n_pad)
 
        # Zero Padding (100% - 15%) tokens
        if max_pred > n_pred:
            n_pad = max_pred - n_pred
            masked_tokens.extend([0] * n_pad)
            masked_pos.extend([0] * n_pad)
 
       
        batch.append([input_ids, segment_ids, masked_tokens, masked_pos, label_test[tokens_a_index]])  # IsNext
          
      
          
    return batch
# Proprecessing Finished
 
batch = make_data_test()
input_ids, segment_ids, masked_tokens, masked_pos, isNext = zip(*batch)
'''>>> a = [1,2,3]
b = [4,5,6]
zipped = zip(a,b)     # 打包为元组的列表
[(1, 4), (2, 5), (3, 6)]
zip(*zipped)          # 与 zip 相反，可理解为解压，为zip的逆过程，可用于矩阵的转置
[(1, 2, 3), (4, 5, 6)]
'''
input_ids, segment_ids, masked_tokens, masked_pos, isNext = \
    torch.LongTensor(input_ids), torch.LongTensor(segment_ids), torch.LongTensor(masked_tokens), \
    torch.LongTensor(masked_pos), torch.LongTensor(isNext)
 
predict_list=[]

for i in range(len(batch)):

    input_ids, segment_ids, masked_tokens, masked_pos, isNext = batch[0]

    print([idx2word[w] for w in input_ids if idx2word[w] != '[PAD]'])
 
    logits_lm, logits_clsf = model(torch.LongTensor([input_ids]), \
                     torch.LongTensor([segment_ids]), torch.LongTensor([masked_pos]))


    logits_lm = logits_lm.data.max(2)[1][0].data.numpy()
    print('masked tokens list : ',[pos for pos in masked_tokens if pos != 0])
    print('predict masked tokens list : ',[pos for pos in logits_lm if pos != 0])


 
    logits_clsf = logits_clsf.data.max(1)[1].data.numpy()[0]
    print('isNext : ', isNext )
    print('predict isNext : ', logits_clsf)
    predict_list.append(logits_clsf)


test_loss = 0
correct = 0
total = 0
target_num =[0,0,0]
predict_num = [0,0,0]
p=0
acc_num =[0,0,0]

for i in label_test:
    target_num[i]+=1

for i in predict_list:
       
      #  print(i.argmax())
        index=int(i)
        if index in [0,1,2]:
            predict_num[index]+=1
    #    print(id2word[index],id2word[p])
       
        if index==label_test[p]:
           
           
            acc_num[index]+=1
        p=p+1


#print(target_num)
#print(predict_num)
#print(acc_num)
recallz=0
precisionz=0
accuracyz=0
F1z=0

ps=0
rs=0
for i in range(3):
    if target_num[i]!=0:
        recallz=acc_num[i]/target_num[i]
    else:
        recallz=0
    if predict_num[i]!=0:
         precisionz=acc_num[i]/predict_num[i]
    else:
        precisionz=0
    ps=ps+precisionz
    rs=rs+recallz
    if recallz+precisionz!=0:
         F1z=2*recallz*precisionz/(recallz+precisionz)+F1z

#recall = [acc_num[i]/target_num[i] for i in range(3)]

#precision = [acc_num[i]/predict_num[i] for i in range(3)]

#F1 = [2*recall[i]*precision[i]/(recall[i]+precision[i]) for i in range(3)]

print()
accuracy = sum(acc_num)/sum(target_num) 


# 打印格式方便复制
print('recall:',rs/3)
print('precision:',ps/3)
print('F1:',F1z/3)
print('accuracy',accuracy)

plt.plot(loss_list,label='BERT')
plt.legend()
plt.title('loss-epoch')
plt.show()