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B站 刘二大人 深度学习 pytorch 第十三讲代码

勇敢的趙迦禾 2022-04-27 阅读 61

用RNN实现 输入name 系统识别country (CPU版本 因此GPU的一些语句省略了~)

1.导入所需包

import torch
import numpy as np
import matplotlib.pyplot as plt
from torch.utils.data import DataLoader
from torch.utils.data import Dataset
from torchvision import transforms
from torchvision import datasets
import torch.nn.functional as F
import torch.optim as optim
import gzip
import csv
import time
import math

2.参数设置

####参数设置
HIDDEN_SIZE = 100
BATCH_SIZE = 256
N_LAYER = 2
N_EPOCHS = 100
N_CHARS = 128 ####输入字典长度
USE_GPU = False

3.NameDataset类

class NameDataset(Dataset):
def __init__(self, is_train_set=True):
filename = 'C:/Users/xxx/Desktop/pytorchliuer/names_train.csv.gz' if is_train_set else 'C:/Users/xxx/Desktop/pytorchliuer/names_test.csv.gz'
with gzip.open(filename,'rt') as f:
reader = csv.reader(f)
rows = list(reader)
self.names = [row[0] for row in rows]
self.len = len(self.names)
self.countries = [row[1] for row in rows]
self.country_list = list(sorted(set(self.countries)))
self.country_dict = self.getCountryDict()
self.country_num = len(self.country_list)

def __getitem__(self, index):
return self.names[index],self.country_dict[self.countries[index]]

def __len__(self):
return self.len

def getCountryDict(self):
country_dict = dict()
for idx,country_name in enumerate(self.country_list,0):
country_dict[country_name] = idx
return country_dict

def idx2country(self,index):
return self.country_list[index]

def getCountriesNum(self):
return self.country_num

4.数据准备工作

####数据准备工作
trainset = NameDataset(is_train_set=True)
trainloader = DataLoader(trainset,batch_size=BATCH_SIZE,shuffle=True)
testset = NameDataset(is_train_set=False)
testloader = DataLoader(testset,batch_size=BATCH_SIZE,shuffle=False)


N_COUNTRY = trainset.getCountriesNum()

5.网络模型

#####模型设计
class RNNClassifier(torch.nn.Module):
def __init__(self,input_size,hidden_size,output_size,n_layers=1,bidirectional=True):
super(RNNClassifier,self).__init__()
self.hidden_size = hidden_size
self.n_layers = n_layers
self.n_directions = 2 if bidirectional else 1
self.embedding = torch.nn.Embedding(input_size,hidden_size)
self.gru = torch.nn.GRU(hidden_size,hidden_size,n_layers,bidirectional=bidirectional)
self.fc = torch.nn.Linear(hidden_size*self.n_directions,output_size)

def __init_hidden(self,batch_size):
hidden = torch.zeros(self.n_layers*self.n_directions,batch_size,self.hidden_size)
return create_tensor(hidden)

def forward(self,input,seq_lengths):
input = input.t()
batch_size = input.size(1)

hidden = self.__init_hidden(batch_size)
embedding = self.embedding(input)

gru_input = torch.nn.utils.rnn.pack_padded_sequence(embedding,seq_lengths)
output,hidden = self.gru(gru_input,hidden)
if self.n_directions == 2:
hidden_cat = torch.cat([hidden[-1],hidden[-2]],dim=1)
else:
hidden_cat = hidden[-1]
fc_output = self.fc(hidden_cat)
return fc_output

6.功能函数构建

def make_tensors(names,countries):
sequences_and_lengths = [name2list(name) for name in names]
name_sequences = [sl[0] for sl in sequences_and_lengths]
seq_lengths = torch.LongTensor([sl[1] for sl in sequences_and_lengths])
countries = countries.long()

seq_tensor = torch.zeros(len(name_sequences),seq_lengths.max()).long()
for idx,(seq,seq_len) in enumerate(zip(name_sequences,seq_lengths),0):
seq_tensor[idx,:seq_len] = torch.LongTensor(seq)

seq_lengths,perm_idx = seq_lengths.sort(dim=0,descending=True)
seq_tensor = seq_tensor[perm_idx]
countries = countries[perm_idx]

return create_tensor(seq_tensor),\
create_tensor(seq_lengths),\
create_tensor(countries)

def name2list(name):
arr = [ord(c) for c in name]
return arr,len(arr)


def create_tensor(tensor):
return tensor


def time_since(since):
s = time.time()-since
m = math.floor(s/60)
s -= m*60
return '%dm %ds' %(m, s)

7.训练

def trainModel():
total_loss = 0
for i,(names,countries) in enumerate(trainloader,1):
inputs,seq_lengths,target = make_tensors(names,countries)
output = classifier(inputs,seq_lengths)
loss = criterion(output,target)
optimizer.zero_grad()
loss.backward()
optimizer.step()

total_loss += loss.item()
if i%10 == 0:
print(f'[{time_since(start)}] Epoch{epoch}', end='')
print(f'[{i*len(inputs)}/{len(trainset)}]', end='')
print(f'loss={total_loss/(i*len(inputs))}')

return total_loss

8.测试

def testModel():
correct = 0
total = len(testset)
print("evaluating trained model ...")
with torch.no_grad():
for i,(names,countries) in enumerate(testloader,1):
inputs, seq_lengths, target = make_tensors(names, countries)
output = classifier(inputs, seq_lengths)
pred = output.max(dim=1,keepdim=True)[1]
correct += pred.eq(target.view_as(pred)).sum().item()

percent = '%.2f' %(100*correct/total)
print(f'Test set: Accuracy {correct}/{total} {percent}%')
return correct/total

9.函数入口

if __name__ == '__main__':
classifier = RNNClassifier(N_CHARS,HIDDEN_SIZE,N_COUNTRY,N_LAYER)

criterion = torch.nn.CrossEntropyLoss()
optimizer = torch.optim.Adam(classifier.parameters(),lr = 0.001)

start = time.time()
print("Training for %d epochs..." % N_EPOCHS)
acc_list = []
for epoch in range(1,N_EPOCHS+1):
trainModel()
acc = testModel()
acc_list.append(acc)

完整代码:

import torch
import numpy as np
import matplotlib.pyplot as plt
from torch.utils.data import DataLoader
from torch.utils.data import Dataset
from torchvision import transforms
from torchvision import datasets
import torch.nn.functional as F
import torch.optim as optim
import gzip
import csv
import time
import math

####参数设置
HIDDEN_SIZE = 100
BATCH_SIZE = 256
N_LAYER = 2
N_EPOCHS = 100
N_CHARS = 128 ####输入字典长度
USE_GPU = False

class NameDataset(Dataset):
def __init__(self, is_train_set=True):
filename = 'C:/Users/xxx/Desktop/pytorchliuer/names_train.csv.gz' if is_train_set else 'C:/Users/xxx/Desktop/pytorchliuer/names_test.csv.gz'
with gzip.open(filename,'rt') as f:
reader = csv.reader(f)
rows = list(reader)
self.names = [row[0] for row in rows]
self.len = len(self.names)
self.countries = [row[1] for row in rows]
self.country_list = list(sorted(set(self.countries)))
self.country_dict = self.getCountryDict()
self.country_num = len(self.country_list)

def __getitem__(self, index):
return self.names[index],self.country_dict[self.countries[index]]

def __len__(self):
return self.len

def getCountryDict(self):
country_dict = dict()
for idx,country_name in enumerate(self.country_list,0):
country_dict[country_name] = idx
return country_dict

def idx2country(self,index):
return self.country_list[index]

def getCountriesNum(self):
return self.country_num

####数据准备工作
trainset = NameDataset(is_train_set=True)
trainloader = DataLoader(trainset,batch_size=BATCH_SIZE,shuffle=True)
testset = NameDataset(is_train_set=False)
testloader = DataLoader(testset,batch_size=BATCH_SIZE,shuffle=False)


N_COUNTRY = trainset.getCountriesNum()

#####模型设计
class RNNClassifier(torch.nn.Module):
def __init__(self,input_size,hidden_size,output_size,n_layers=1,bidirectional=True):
super(RNNClassifier,self).__init__()
self.hidden_size = hidden_size
self.n_layers = n_layers
self.n_directions = 2 if bidirectional else 1
self.embedding = torch.nn.Embedding(input_size,hidden_size)
self.gru = torch.nn.GRU(hidden_size,hidden_size,n_layers,bidirectional=bidirectional)
self.fc = torch.nn.Linear(hidden_size*self.n_directions,output_size)

def __init_hidden(self,batch_size):
hidden = torch.zeros(self.n_layers*self.n_directions,batch_size,self.hidden_size)
return create_tensor(hidden)

def forward(self,input,seq_lengths):
input = input.t()
batch_size = input.size(1)

hidden = self.__init_hidden(batch_size)
embedding = self.embedding(input)

gru_input = torch.nn.utils.rnn.pack_padded_sequence(embedding,seq_lengths)
output,hidden = self.gru(gru_input,hidden)
if self.n_directions == 2:
hidden_cat = torch.cat([hidden[-1],hidden[-2]],dim=1)
else:
hidden_cat = hidden[-1]
fc_output = self.fc(hidden_cat)
return fc_output

def make_tensors(names,countries):
sequences_and_lengths = [name2list(name) for name in names]
name_sequences = [sl[0] for sl in sequences_and_lengths]
seq_lengths = torch.LongTensor([sl[1] for sl in sequences_and_lengths])
countries = countries.long()

seq_tensor = torch.zeros(len(name_sequences),seq_lengths.max()).long()
for idx,(seq,seq_len) in enumerate(zip(name_sequences,seq_lengths),0):
seq_tensor[idx,:seq_len] = torch.LongTensor(seq)

seq_lengths,perm_idx = seq_lengths.sort(dim=0,descending=True)
seq_tensor = seq_tensor[perm_idx]
countries = countries[perm_idx]

return create_tensor(seq_tensor),\
create_tensor(seq_lengths),\
create_tensor(countries)

def name2list(name):
arr = [ord(c) for c in name]
return arr,len(arr)

def time_since(since):
s = time.time()-since
m = math.floor(s/60)
s -= m*60
return '%dm %ds' %(m, s)

def create_tensor(tensor):
return tensor

def trainModel():
total_loss = 0
for i,(names,countries) in enumerate(trainloader,1):
inputs,seq_lengths,target = make_tensors(names,countries)
output = classifier(inputs,seq_lengths)
loss = criterion(output,target)
optimizer.zero_grad()
loss.backward()
optimizer.step()

total_loss += loss.item()
if i%10 == 0:
print(f'[{time_since(start)}] Epoch{epoch}', end='')
print(f'[{i*len(inputs)}/{len(trainset)}]', end='')
print(f'loss={total_loss/(i*len(inputs))}')

return total_loss

def testModel():
correct = 0
total = len(testset)
print("evaluating trained model ...")
with torch.no_grad():
for i,(names,countries) in enumerate(testloader,1):
inputs, seq_lengths, target = make_tensors(names, countries)
output = classifier(inputs, seq_lengths)
pred = output.max(dim=1,keepdim=True)[1]
correct += pred.eq(target.view_as(pred)).sum().item()

percent = '%.2f' %(100*correct/total)
print(f'Test set: Accuracy {correct}/{total} {percent}%')
return correct/total

if __name__ == '__main__':
classifier = RNNClassifier(N_CHARS,HIDDEN_SIZE,N_COUNTRY,N_LAYER)

criterion = torch.nn.CrossEntropyLoss()
optimizer = torch.optim.Adam(classifier.parameters(),lr = 0.001)

start = time.time()
print("Training for %d epochs..." % N_EPOCHS)
acc_list = []
for epoch in range(1,N_EPOCHS+1):
trainModel()
acc = testModel()
acc_list.append(acc)

输出:训练了20个epoch:

 

 

 

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