pytorch seq2seq模型训练测试

num_sequence.py

"""
数字序列化方法
"""

class NumSequence:
    """
    input : intintint
    output :[int,int,int]
    """
    PAD_TAG = "<PAD>"
    UNK_TAG = "<UNK>"
    SOS_TAG = "<SOS>"
    EOS_TAG = "<EOS>"

    PAD = 0
    UNK = 1
    SOS = 2
    EOS = 3

    def __init__(self):
        self.dict = {
            self.PAD_TAG:self.PAD,
            self.UNK_TAG: self.UNK,
            self.SOS_TAG: self.SOS,
            self.EOS_TAG: self.EOS
        }
        #0--》int ,1--->int,2--->int
        for i in range(0,10):
            self.dict[str(i)] = len(self.dict)
        self.inverse_dict = dict(zip(self.dict.values(),self.dict.keys()))

    def transform(self,sentence,max_len=None,add_eos=False):
        """
        实现转化为数字序列
        :param sentence: list() ,["1","2","5"...str]
        :param max_len: int
        :param add_eos: 是否要添加结束符
        :return: [int,int,int]

        """

        if add_eos : #不是必须的，仅仅是为了最终句子的长度=设置的max；如果没有，最终的句子长度= max_len+1
            max_len = max_len - 1
        if max_len is not None:
            if len(sentence)> max_len:
                sentence = sentence[:max_len]
            else:
                sentence = sentence + [self.PAD_TAG]*(max_len-len(sentence))
        if add_eos:
            if sentence[-1] == self.PAD_TAG:  #句子中有PAD，在PAD之前添加EOS
                pad_index = sentence.index(self.PAD_TAG)
                sentence.insert(pad_index,self.EOS_TAG)
            else:#句子中没有PAD，在最后添加EOS
                sentence += [self.EOS_TAG]

        return [self.dict.get(i,self.UNK) for i in sentence]

    def inverse_transform(self,incides):
        """
        把序列转化为数字
        :param incides:[1,3,4,5,2,]
        :return: "12312312"
        """
        result = []
        for i in incides:
            temp = self.inverse_dict.get(i, self.UNK_TAG)
            if temp != self.EOS_TAG:  #把EOS之后的内容删除，123---》1230EOS，predict 1230EOS123
                result.append(temp)
            else:
                break

        return "".join(result)

    def __len__(self):
        return len(self.dict)


if __name__ == '__main__':
    num_Sequence = NumSequence()
    print(num_Sequence.dict)
    s = list("123123")
    ret = num_Sequence.transform(s)
    print(ret)
    ret = num_Sequence.inverse_transform(ret)
    print(ret)

　　dataset.py

"""
准备数据集
"""
from torch.utils.data import DataLoader,Dataset
import numpy as np
import config
import torch

class NumDataset(Dataset):
    def __init__(self,train=True):
        np.random.seed(9) if train else np.random.seed(10)
        self.size = 400000 if train else 100000
        self.data = np.random.randint(1,1e8,size=self.size)

    def __len__(self):
        return self.size

    def __getitem__(self, idx):
        input = list(str(self.data[idx]))
        target = input+["0"]
        return input,target,len(input),len(target)

def collate_fn(batch):
    """
    :param batch:[(一个getitem的结果)，(一个getitem的结果)，(一个getitem的结果)、、、、]
    :return:
    """
    #把batch中的数据按照input的长度降序排序
    batch = sorted(batch,key=lambda x:x[-2],reverse=True)
    input,target,input_len,target_len = zip(*batch)
    input = torch.LongTensor([config.ns.transform(i,max_len=config.max_len) for i in input])
    target = torch.LongTensor([config.ns.transform(i,max_len=config.max_len,add_eos=True) for i in target])
    input_len = torch.LongTensor(input_len)
    target_len = torch.LongTensor(target_len)
    return input,target,input_len,target_len

def get_dataloader(train=True):
    batch_size = config.train_batchsize if train else config.test_batch_size
    return DataLoader(NumDataset(train),batch_size=batch_size,shuffle=False,collate_fn=collate_fn)


if __name__ == '__main__':
    loader = get_dataloader(train=False)
    for idx,(input,target,input_len,target_len) in enumerate(loader):
        print(idx)
        print(input)
        print(target)
        print(input_len)
        print(target_len)
        break

　　config.py

"""
配置文件
"""
from num_sequence import NumSequence
import torch

device= torch.device("cpu")
# device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu")

train_batchsize = 256
test_batch_size = 1000


ns = NumSequence()
max_len = 10

　　encoder.py

"""
进行编码
"""

import torch.nn as nn
from torch.nn.utils.rnn import pad_packed_sequence,pack_padded_sequence
import config


class Encoder(nn.Module):
    def __init__(self):
        super(Encoder,self).__init__()
        self.embedding = nn.Embedding(num_embeddings=len(config.ns),
                                     embedding_dim=50,
                                     padding_idx=config.ns.PAD
                                     )
        self.gru = nn.GRU(input_size=50,
                          hidden_size=64,
                          num_layers=1,
                          batch_first=True,
                          bidirectional=False,
                          dropout=0)


    def forward(self, input,input_len):
        input_embeded = self.embedding(input)

        #对输入进行打包
        input_packed = pack_padded_sequence(input_embeded,input_len,batch_first=True)
        #经过GRU处理
        output,hidden = self.gru(input_packed)
        # print("encoder gru hidden:",hidden.size())
        #进行解包
        output_paded,seq_len = pad_packed_sequence(output,batch_first=True,padding_value=config.ns.PAD)
        return output_paded,hidden  #[1,batch_size,encoder_hidden_size]

　　decoder.py

"""
实现解码器
"""
import torch.nn as nn
import config
import torch
import torch.nn.functional as F
import numpy as np


class Decoder(nn.Module):
    def __init__(self):
        super(Decoder,self).__init__()

        self.embedding = nn.Embedding(num_embeddings=len(config.ns),
                                      embedding_dim=50,
                                      padding_idx=config.ns.PAD)

        #需要的hidden_state形状：[1,batch_size,64]
        self.gru = nn.GRU(input_size=50,
                          hidden_size=64,
                          num_layers=1,
                          bidirectional=False,
                          batch_first=True,
                          dropout=0)

        #假如encoder的hidden_size=64，num_layer=1 encoder_hidden :[2,batch_sizee,64]

        self.fc = nn.Linear(64,len(config.ns))

    def forward(self, encoder_hidden):

        #第一个时间步的输入的hidden_state
        decoder_hidden = encoder_hidden  #[1,batch_size,encoder_hidden_size]
        #第一个时间步的输入的input
        batch_size = encoder_hidden.size(1)
        decoder_input = torch.LongTensor([[config.ns.SOS]]*batch_size).to(config.device)         #[batch_size,1]
        # print("decoder_input:",decoder_input.size())


        #使用全为0的数组保存数据，[batch_size,max_len,vocab_size]
        decoder_outputs = torch.zeros([batch_size,config.max_len,len(config.ns)]).to(config.device)

        for t in range(config.max_len):
            decoder_output_t,decoder_hidden = self.forward_step(decoder_input,decoder_hidden)
            decoder_outputs[:,t,:] = decoder_output_t

            #获取当前时间步的预测值
            value,index = decoder_output_t.max(dim=-1)
            decoder_input = index.unsqueeze(-1)  #[batch_size,1]
            # print("decoder_input:",decoder_input.size())
        return decoder_outputs,decoder_hidden


    def forward_step(self,decoder_input,decoder_hidden):
        '''
        计算一个时间步的结果
        :param decoder_input: [batch_size,1]
        :param decoder_hidden: [batch_size,encoder_hidden_size]
        :return:
        '''

        decoder_input_embeded = self.embedding(decoder_input)
        # print("decoder_input_embeded:",decoder_input_embeded.size())

        out,decoder_hidden = self.gru(decoder_input_embeded,decoder_hidden)

        #out ：【batch_size,1,hidden_size】

        out_squeezed = out.squeeze(dim=1) #去掉为1的维度
        out_fc = F.log_softmax(self.fc(out_squeezed),dim=-1) #[bathc_size,vocab_size]
        # out_fc.unsqueeze_(dim=1) #[bathc_size,1,vocab_size]
        # print("out_fc:",out_fc.size())
        return out_fc,decoder_hidden

    def evaluate(self,encoder_hidden):

        # 第一个时间步的输入的hidden_state
        decoder_hidden = encoder_hidden  # [1,batch_size,encoder_hidden_size]
        # 第一个时间步的输入的input
        batch_size = encoder_hidden.size(1)
        decoder_input = torch.LongTensor([[config.ns.SOS]] * batch_size).to(config.device)  # [batch_size,1]
        # print("decoder_input:",decoder_input.size())

        # 使用全为0的数组保存数据，[batch_size,max_len,vocab_size]
        decoder_outputs = torch.zeros([batch_size, config.max_len, len(config.ns)]).to(config.device)

        decoder_predict = []  #[[],[],[]]  #123456  ,targe:123456EOS,predict:123456EOS123
        for t in range(config.max_len):
            decoder_output_t, decoder_hidden = self.forward_step(decoder_input, decoder_hidden)
            decoder_outputs[:, t, :] = decoder_output_t

            # 获取当前时间步的预测值
            value, index = decoder_output_t.max(dim=-1)
            decoder_input = index.unsqueeze(-1)  # [batch_size,1]
            # print("decoder_input:",decoder_input.size())
            decoder_predict.append(index.cpu().detach().numpy())

        #返回预测值
        decoder_predict = np.array(decoder_predict).transpose() #[batch_size,max_len]
        return decoder_outputs, decoder_predict

　　seq2seq.py

"""
完成seq2seq模型
"""
import torch.nn as nn
from encoder import Encoder
from decoder import Decoder


class Seq2Seq(nn.Module):
    def __init__(self):
        super(Seq2Seq,self).__init__()
        self.encoder = Encoder()
        self.decoder = Decoder()

    def forward(self, input,input_len):
        encoder_outputs,encoder_hidden = self.encoder(input,input_len)
        decoder_outputs,decoder_hidden = self.decoder(encoder_hidden)
        return decoder_outputs

    def evaluate(self,input,input_len):
        encoder_outputs, encoder_hidden = self.encoder(input, input_len)
        decoder_outputs, decoder_predict = self.decoder.evaluate(encoder_hidden)
        return decoder_outputs,decoder_predict

　　train.py

"""
进行模型的训练
"""
import torch
import torch.nn.functional as F
from seq2seq import Seq2Seq
from torch.optim import Adam
from dataset import get_dataloader
from tqdm import tqdm
import config
import numpy as np
import pickle
from matplotlib import pyplot as plt
from eval import eval
import os

model = Seq2Seq().to(config.device)
optimizer = Adam(model.parameters())

if os.path.exists("./models/model.pkl"):
    model.load_state_dict(torch.load("./models/model.pkl"))
    optimizer.load_state_dict(torch.load("./models/optimizer.pkl"))

loss_list = []

def train(epoch):
    data_loader = get_dataloader(train=True)
    bar = tqdm(data_loader,total=len(data_loader))

    for idx,(input,target,input_len,target_len) in enumerate(bar):
        input = input.to(config.device)
        target = target.to(config.device)
        input_len = input_len.to(config.device)
        optimizer.zero_grad()
        decoder_outputs = model(input,input_len) #[batch_Size,max_len,vocab_size]
        predict = decoder_outputs.view(-1,len(config.ns))
        target = target.view(-1)
        loss = F.nll_loss(predict,target,ignore_index=config.ns.PAD)
        loss.backward()
        optimizer.step()
        loss_list.append(loss.item())
        bar.set_description("epoch:{} idx:{} loss:{:.6f}".format(epoch,idx,np.mean(loss_list)))

        if idx%100 == 0:
            torch.save(model.state_dict(),"./models/model.pkl")
            torch.save(optimizer.state_dict(),"./models/optimizer.pkl")
            pickle.dump(loss_list,open("./models/loss_list.pkl","wb"))


if __name__ == '__main__':
    for i in range(5):
        train(i)
        eval()

    plt.figure(figsize=(50,8))
    plt.plot(range(len(loss_list)),loss_list)
    plt.show()

　　eval.py

"""
进行模型的评估
"""

import torch
import torch.nn.functional as F
from seq2seq import Seq2Seq
from torch.optim import Adam
from dataset import get_dataloader
from tqdm import tqdm
import config
import numpy as np
import pickle
from matplotlib import pyplot as plt



def eval():
    model = Seq2Seq().to(config.device)
    model.load_state_dict(torch.load("./models/model.pkl"))

    loss_list = []
    acc_list = []
    data_loader = get_dataloader(train=False) #获取测试集
    with torch.no_grad():
        for idx,(input,target,input_len,target_len) in enumerate(data_loader):
            input = input.to(config.device)
            # target = target #[batch_size,max_len]
            input_len = input_len.to(config.device)
            #decoder_predict:[batch_size,max_len]
            decoder_outputs,decoder_predict = model.evaluate(input,input_len) #[batch_Size,max_len,vocab_size]
            loss = F.nll_loss(decoder_outputs.view(-1,len(config.ns)),target.to(config.device).view(-1),ignore_index=config.ns.PAD)
            loss_list.append(loss.item())

            #把traget 和 decoder_predict进行inverse_transform
            target_inverse_tranformed = [config.ns.inverse_transform(i) for i in target.numpy()]
            predict_inverse_tranformed = [config.ns.inverse_transform(i)for i in decoder_predict]
            cur_eq =[1 if target_inverse_tranformed[i] == predict_inverse_tranformed[i] else 0 for i in range(len(target_inverse_tranformed))]
            acc_list.extend(cur_eq)
            # print(np.mean(cur_eq))


    print("mean acc:{} mean loss:{:.6f}".format(np.mean(acc_list),np.mean(loss_list)))



def interface(_input): #进行预测
    model = Seq2Seq().to(config.device)
    model.load_state_dict(torch.load("./models/model.pkl"))
    input = list(str(_input))
    input_len = torch.LongTensor([len(input)]) #[1]
    input = torch.LongTensor([config.ns.transform(input)])  #[1,max_len]

    with torch.no_grad():
        input = input.to(config.device)
        input_len = input_len.to(config.device)
        _, decoder_predict = model.evaluate(input, input_len)  # [batch_Size,max_len,vocab_size]
        # decoder_predict进行inverse_transform
        pred = [config.ns.inverse_transform(i) for i in decoder_predict]
        print(_input,"---->",pred[0])


if __name__ == '__main__':
    interface("89767678")