Python 10 训练模型

原文：https://www.cnblogs.com/denny402/p/7520063.html

原文：https://www.jianshu.com/p/84f72791806f

原文：https://blog.csdn.net/lee813/article/details/89609691

1、下载fashion-mnist数据集

　　地址：https://github.com/zalandoresearch/fashion-mnist

　　下面这四个都要下载，下载完成后，解压到同一个目录，我是解压到“E:/fashion_mnist/”这个目录里面，好和下面的代码目录一致

2、在Geany中执行下面这段代码。

　　这段代码里面，需要先用pip安装skimage、torch、torchvision，前两篇文章有安装步骤。

　　这段代码的作用：将下载下来的 二进制文件 转换为 图片，会在目录中生成两个文件夹和两个文本。

　　　　　　　　　　文件夹里面全是图片，图片的内容是数字，N多数字。

　　　　　　　　　　文本的内容主要是图片和真实数字的一个关联。

import os
from skimage import io
import torchvision.datasets.mnist as mnist

root="E:/fashion_mnist/"
train_set = (
    mnist.read_image_file(os.path.join(root, 'train-images-idx3-ubyte')),
    mnist.read_label_file(os.path.join(root, 'train-labels-idx1-ubyte'))
        )
test_set = (
    mnist.read_image_file(os.path.join(root, 't10k-images-idx3-ubyte')),
    mnist.read_label_file(os.path.join(root, 't10k-labels-idx1-ubyte'))
        )
print("training set :",train_set[0].size())
print("test set :",test_set[0].size())

def convert_to_img(train=True):
    if(train):
        f=open(root+'train.txt','w')
        data_path=root+'/train/'
        if(not os.path.exists(data_path)):
            os.makedirs(data_path)
        for i, (img,label) in enumerate(zip(train_set[0],train_set[1])):
            img_path=data_path+str(i)+'.jpg'
            io.imsave(img_path,img.numpy())
            f.write(img_path+' '+str(label)+'
')
        f.close()
    else:
        f = open(root + 'test.txt', 'w')
        data_path = root + '/test/'
        if (not os.path.exists(data_path)):
            os.makedirs(data_path)
        for i, (img,label) in enumerate(zip(test_set[0],test_set[1])):
            img_path = data_path+ str(i) + '.jpg'
            io.imsave(img_path, img.numpy())
            f.write(img_path + ' ' + str(label) + '
')
        f.close()

convert_to_img(True)
convert_to_img(False)

3、原文的这段代码编译会出错，主要是跟下载的数据有关，数据格式不一样，这里还在处理，原因是找到了的，就一个int的转换，下面贴出改过后的代码

 出错的地方：

import torch
import re
import numpy
from torch.autograd import Variable
from torchvision import transforms
from torch.utils.data import Dataset, DataLoader
from PIL import Image
root="E:/fashion_mnist/"


def default_loader(path):
    return Image.open(path).convert('RGB')
class MyDataset(Dataset):
    def __init__(self, txt, transform=None, target_transform=None, loader=default_loader):
        fh = open(txt, 'r')
        imgs = []
        for line in fh:
            line = line.strip('
')
            line = line.rstrip()
            words = line.split()
            p1 = re.compile(r'[(](.*?)[)]', re.S)
            arr = re.findall(p1, words[1])
            word = arr[0]
            imgs.append((words[0],int(word)))
        self.imgs = imgs
        self.transform = transform
        self.target_transform = target_transform
        self.loader = loader

    def __getitem__(self, index):
        fn, label = self.imgs[index]
        img = self.loader(fn)
        if self.transform is not None:
            img = self.transform(img)
        return img,label

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

train_data=MyDataset(txt=root+'train.txt', transform=transforms.ToTensor())
test_data=MyDataset(txt=root+'test.txt', transform=transforms.ToTensor())
train_loader = DataLoader(dataset=train_data, batch_size=64, shuffle=True)
test_loader = DataLoader(dataset=test_data, batch_size=64)

 3、原文的代码，还有一部分也会报错，ERROR如下。

　　唉，感叹一下，下次还是看一下语法那些，能读懂了代码再改吧，本想怎个拿来主义的，结果拿来了还是不能运行

　　解决-原文地址：https://blog.csdn.net/weixin_43848267/article/details/88874584

　　解决：将 loss_return.data[0] 改为 loss_return.data

　　　　　　还有几个地方 也要将 .data[0] 改为 .data

4、可完整运行的代码

代码1：

import os
from skimage import io
import torchvision.datasets.mnist as mnist

root="E:/fashion_mnist/"
train_set = (
    mnist.read_image_file(os.path.join(root, 'train-images-idx3-ubyte')),
    mnist.read_label_file(os.path.join(root, 'train-labels-idx1-ubyte'))
        )
test_set = (
    mnist.read_image_file(os.path.join(root, 't10k-images-idx3-ubyte')),
    mnist.read_label_file(os.path.join(root, 't10k-labels-idx1-ubyte'))
        )
print("training set :",train_set[0].size())
print("test set :",test_set[0].size())

def convert_to_img(train=True):
    if(train):
        f=open(root+'train.txt','w')
        data_path=root+'/train/'
        if(not os.path.exists(data_path)):
            os.makedirs(data_path)
        for i, (img,label) in enumerate(zip(train_set[0],train_set[1])):
            img_path=data_path+str(i)+'.jpg'
            io.imsave(img_path,img.numpy())
            f.write(img_path+' '+str(label)+'
')
        f.close()
    else:
        f = open(root + 'test.txt', 'w')
        data_path = root + '/test/'
        if (not os.path.exists(data_path)):
            os.makedirs(data_path)
        for i, (img,label) in enumerate(zip(test_set[0],test_set[1])):
            img_path = data_path+ str(i) + '.jpg'
            io.imsave(img_path, img.numpy())
            f.write(img_path + ' ' + str(label) + '
')
        f.close()

convert_to_img(True)
convert_to_img(False)

代码2：

import re
import numpy
import torch
from torch.autograd import Variable
from torchvision import transforms
from torch.utils.data import Dataset, DataLoader
from PIL import Image
root="E:/fashion_mnist/"

# -----------------ready the dataset--------------------------
def default_loader(path):
    return Image.open(path).convert('RGB')
class MyDataset(Dataset):
    def __init__(self, txt, transform=None, target_transform=None, loader=default_loader):
        fh = open(txt, 'r')
        imgs = []
        for line in fh:
            line = line.strip('
')
            line = line.rstrip()
            words = line.split()
            
            p1 = re.compile(r'[(](.*?)[)]', re.S) 
            arr = re.findall(p1, words[1])
            word = arr[0]
            
            imgs.append((words[0],int(word)))
        self.imgs = imgs
        self.transform = transform
        self.target_transform = target_transform
        self.loader = loader

    def __getitem__(self, index):
        fn, label = self.imgs[index]
        img = self.loader(fn)
        if self.transform is not None:
            img = self.transform(img)
        return img,label

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

train_data=MyDataset(txt=root+'train.txt', transform=transforms.ToTensor())
test_data=MyDataset(txt=root+'test.txt', transform=transforms.ToTensor())
train_loader = DataLoader(dataset=train_data, batch_size=64, shuffle=True)
test_loader = DataLoader(dataset=test_data, batch_size=64)


#-----------------create the Net and training------------------------

class Net(torch.nn.Module):
    def __init__(self):
        super(Net, self).__init__()
        self.conv1 = torch.nn.Sequential(
            torch.nn.Conv2d(3, 32, 3, 1, 1),
            torch.nn.ReLU(),
            torch.nn.MaxPool2d(2))
        self.conv2 = torch.nn.Sequential(
            torch.nn.Conv2d(32, 64, 3, 1, 1),
            torch.nn.ReLU(),
            torch.nn.MaxPool2d(2)
        )
        self.conv3 = torch.nn.Sequential(
            torch.nn.Conv2d(64, 64, 3, 1, 1),
            torch.nn.ReLU(),
            torch.nn.MaxPool2d(2)
        )
        self.dense = torch.nn.Sequential(
            torch.nn.Linear(64 * 3 * 3, 128),
            torch.nn.ReLU(),
            torch.nn.Linear(128, 10)
        )

    def forward(self, x):
        conv1_out = self.conv1(x)
        conv2_out = self.conv2(conv1_out)
        conv3_out = self.conv3(conv2_out)
        res = conv3_out.view(conv3_out.size(0), -1)
        out = self.dense(res)
        return out


model = Net()
print(model)

optimizer = torch.optim.Adam(model.parameters())
loss_func = torch.nn.CrossEntropyLoss()

for epoch in range(10):
    print('epoch {}'.format(epoch + 1))
    # training-----------------------------
    train_loss = 0.
    train_acc = 0.
    for batch_x, batch_y in train_loader:
        batch_x, batch_y = Variable(batch_x), Variable(batch_y)
        out = model(batch_x)
        loss = loss_func(out, batch_y)
        train_loss += loss.item()
        pred = torch.max(out, 1)[1]
        train_correct = (pred == batch_y).sum()
        train_acc += train_correct.item()
        
        optimizer.zero_grad()
        loss.backward()
        optimizer.step()
    print('Train Loss: {:.6f}, Acc: {:.6f}'.format(train_loss / (len(
        train_data)), train_acc / (len(train_data))))

    # evaluation--------------------------------
    model.eval()
    eval_loss = 0.
    eval_acc = 0.
    for batch_x, batch_y in test_loader:
        batch_x, batch_y = Variable(batch_x), Variable(batch_y)
        out = model(batch_x)
        loss = loss_func(out, batch_y)
        eval_loss += loss.item()
        pred = torch.max(out, 1)[1]
        num_correct = (pred == batch_y).sum()
        eval_acc += num_correct.item()
    print('Test Loss: {:.6f}, Acc: {:.6f}'.format(eval_loss / (len(
        test_data)), eval_acc / (len(test_data))))

 5、总结

　　提示：训练模型有点耗时，这里注意一下

　　　　图片如果过小，标签页里面单独打开图片会大些，排版搞得屁理解一下，一来没时间写文章，二来排版还没学，以后空了就会学。还是先把文章的质量提高了来

　　出现的问题主要是因为 torch的版本不同造成的，所以一会我把 我这里的环境贴出来，避免发生同样的错误。

6、环境

　　系统：win7 64位

　　Python 3.7.3

　　各个包的版本号，其它的好像就没啥了

　　

可测试代码-版本2

代码1：

#coding=utf-8

import os
from skimage import io
import torchvision.datasets.mnist as mnist

root="E:/fashion_mnist/"
train_set = (
    mnist.read_image_file(os.path.join(root, 'train-images-idx3-ubyte')),
    mnist.read_label_file(os.path.join(root, 'train-labels-idx1-ubyte'))
        )
test_set = (
    mnist.read_image_file(os.path.join(root, 't10k-images-idx3-ubyte')),
    mnist.read_label_file(os.path.join(root, 't10k-labels-idx1-ubyte'))
        )
print("training set :",train_set[0].size())
print("test set :",test_set[0].size())

def convert_to_img(train=True):
    if(train):
        f=open(root+'train.txt','w')
        data_path=root+'/train/'
        if(not os.path.exists(data_path)):
            os.makedirs(data_path)
        for i, (img,label) in enumerate(zip(train_set[0],train_set[1])):
            img_path=data_path+str(i)+'.jpg'            
            io.imsave(img_path,img.numpy())
            f.write(img_path+' '+str(label.numpy())+'
') # label改为label.numpy()
        f.close()
    else:
        f = open(root + 'test.txt', 'w')
        data_path = root + '/test/'
        if (not os.path.exists(data_path)):
            os.makedirs(data_path)
        for i, (img,label) in enumerate(zip(test_set[0],test_set[1])):
            img_path = data_path+ str(i) + '.jpg'
            io.imsave(img_path, img.numpy())
            f.write(img_path + ' ' + str(label.numpy()) + '
')
        f.close()

convert_to_img(True)
convert_to_img(False)

代码2：

import torch
from torch.autograd import Variable
from torchvision import transforms
from torch.utils.data import Dataset, DataLoader
from PIL import Image
root="E:/fashion_mnist/"


def default_loader(path):
    return Image.open(path).convert('RGB')
class MyDataset(Dataset):
    def __init__(self, txt, transform=None, target_transform=None, loader=default_loader):
        fh = open(txt, 'r')
        imgs = []
        for line in fh:
            line = line.strip('
')
            line = line.rstrip()
            words = line.split()            
            imgs.append((words[0],int(words[1])))
        self.imgs = imgs
        self.transform = transform
        self.target_transform = target_transform
        self.loader = loader

    def __getitem__(self, index):
        fn, label = self.imgs[index]
        img = self.loader(fn)
        if self.transform is not None:
            img = self.transform(img)
        return img,label

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

train_data=MyDataset(txt=root+'train.txt', transform=transforms.ToTensor())
test_data=MyDataset(txt=root+'test.txt', transform=transforms.ToTensor())
train_loader = DataLoader(dataset=train_data, batch_size=64, shuffle=True)
test_loader = DataLoader(dataset=test_data, batch_size=64)





#-----------------create the Net and training------------------------

class Net(torch.nn.Module):
    def __init__(self):
        super(Net, self).__init__()
        self.conv1 = torch.nn.Sequential(
            torch.nn.Conv2d(3, 32, 3, 1, 1),
            torch.nn.ReLU(),
            torch.nn.MaxPool2d(2))
        self.conv2 = torch.nn.Sequential(
            torch.nn.Conv2d(32, 64, 3, 1, 1),
            torch.nn.ReLU(),
            torch.nn.MaxPool2d(2)
        )
        self.conv3 = torch.nn.Sequential(
            torch.nn.Conv2d(64, 64, 3, 1, 1),
            torch.nn.ReLU(),
            torch.nn.MaxPool2d(2)
        )
        self.dense = torch.nn.Sequential(
            torch.nn.Linear(64 * 3 * 3, 128),
            torch.nn.ReLU(),
            torch.nn.Linear(128, 10)
        )

    def forward(self, x):
        conv1_out = self.conv1(x)
        conv2_out = self.conv2(conv1_out)
        conv3_out = self.conv3(conv2_out)
        res = conv3_out.view(conv3_out.size(0), -1)
        out = self.dense(res)
        return out


model = Net()
print(model)

optimizer = torch.optim.Adam(model.parameters())
loss_func = torch.nn.CrossEntropyLoss()

for epoch in range(10):
    print('epoch {}'.format(epoch + 1))
    # training-----------------------------
    train_loss = 0.
    train_acc = 0.
    for batch_x, batch_y in train_loader:
        batch_x, batch_y = Variable(batch_x), Variable(batch_y)
        out = model(batch_x)
        loss = loss_func(out, batch_y)        
        train_loss += loss.data
        pred = torch.max(out, 1)[1]
        train_correct = (pred == batch_y).sum()
        train_acc += train_correct.data
        optimizer.zero_grad()
        loss.backward()
        optimizer.step()
    print('Train Loss: {:.6f}, Acc: {:.6f}'.format(train_loss / (len(
        train_data)), train_acc / (len(train_data))))

    # evaluation--------------------------------
    model.eval()
    eval_loss = 0.
    eval_acc = 0.
    for batch_x, batch_y in test_loader:
        batch_x, batch_y = Variable(batch_x, volatile=True), Variable(batch_y, volatile=True)
        out = model(batch_x)
        loss = loss_func(out, batch_y)
        eval_loss += loss.data
        pred = torch.max(out, 1)[1]
        num_correct = (pred == batch_y).sum()
        eval_acc += num_correct.data
    print('Test Loss: {:.6f}, Acc: {:.6f}'.format(eval_loss / (len(
        test_data)), eval_acc / (len(test_data))))

 版本2修改的地方

原文：https://blog.csdn.net/shang_jia/article/details/82936074

原文：https://www.liangzl.com/get-article-detail-8524.html

注意：下面的代码不管，下面是第一次测试的时候，下载错了数据集

问题：这里的数据集是数字，不是这个数据集，代码里面是用的fashion-mnist这个数据集

1、下载mnist数据集

　　地址：http://yann.lecun.com/exdb/mnist/

　　下面这四个都要下载，下载完成后，解压到同一个目录，我是解压到“E:/fashion_mnist/”这个目录里面，好和下面的代码目录一致

　　解压完成后，需要修改一下文件名，如（修改原因：保持和下面代码一样，避免出现其它问题）：

　　　　修改前：t10k-images.idx3-ubyte

　　　　修改后：t10k-images-idx3-ubyte

　　我是第一次弄这玩意，所以尽量弄得白痴些，走弯路很烦，有时候一点点小问题就弄半天，其实就是别人有那么一点没讲清楚，然后就会搞很久