pytorch实战

pytorch实战

本文出现的代码在 https://github.com/hudiework/PyTorchOrigin.git的master分支上

学完本课程之后：

1. 读读深度学习的花书，夯实理论基础
2. 通读一遍PyTorch官方文档，知道提供了什么功能以及文档结构
3. 复现经典工作（读代码=》写代码=》读代码=》…循环往复）
4. 扩充视野，广泛阅读自己领域内的工作，看看别人的工作有没有自己不会复现的块

线性模型

Overview

• 目标：
• 如何使用PyTorch实现神经网络/深度学习的基础学习系统
• 需求：
• 线性代数、概率论、python

人类智能

1. information→infer
2. image→prediction

人工智能

算法代替人脑进行处理的过程

监督学习

​ 拿出数据集，打过标签的，知道答案，建立模型，训练模型，得到算法

范围

基于规则的系统

经典机器学习

表示学习

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提取features

维度诅咒

维数增加，数据需求量增大

降维

eg: n维→3维

[ ] = [ ] [ ]

3x1 3xn nx1

找到3xn的矩阵

深度学习

传统策略

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SVM问题

1. 手工设计功能的限制。
2. 支持向量机不能很好地处理大数据集。
3. 越来越多的应用程序需要处理非结构化数据。

import numpy as np
import matplotlib.pyplot as plt

# 准备数据

x_data = [1.0, 2.0, 3.0]
y_data = [2.0, 4.0, 6.0]

w=0
# define the model

def forward(x):
    return x * w


def loss(x, y):
    y_pred = forward(x)
    return (y_pred - y) ** 2


# prepare two list to draw the graph

w_list = []
mse_list = []

# 穷举过程
for w in np.arange(0.0, 4.1, 0.1):
    print("w=", w)
    l_sum = 0
    for x_val, y_val in zip(x_data, y_data):
        y_pred_val = forward(x_val)
        loss_val = loss(x_val, y_val)
        l_sum += loss_val
        print('\t', x_val, y_val, y_pred_val, loss_val)
    print("MSE=", l_sum / 3)
    w_list.append(w)
    mse_list.append(l_sum / 3)

# draw the graph

plt.plot(w_list, mse_list)
plt.ylabel("Loss")
plt.xlabel("w")
plt.show()

线性模型课后习题

p5:

1. 梯度归零为啥不是在反向传播的后面

可以理解为反向传播是用来算参数的梯度的。

所以要先梯度归零

然后反向传播算出梯度

然后“参数=参数-梯度*学习率”，进行梯度下降更新。

p6:

1. F没有定义

import torch.nn.functional as F

但是，torch.nn.functional.sigmoid函数好像要停用了。运行会提示建议更改为torch.sigmoid函数

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D

# prepare dataset, y=2x+3

x_data = [1.0, 2.0, 3.0]
y_data = [5.0, 7.0, 9.0]

# 生成矩阵坐标
W, B = np.arange(0.0, 4.1, 0.1).round(1), np.arange(0.0, 4.1, 0.1).round(1)
w, b = np.meshgrid(W, B)


def forward(x):
    return x * w + b


def loss(x, y):
    y_pred = forward(x)
    return (y_pred - y) ** 2


l_sum = 0
for x_val, y_val in zip(x_data, y_data):
    loss_val = loss(x_val, y_val)
    l_sum += loss_val

mse = l_sum / len(x_data)

# 绘图

fig = plt.figure()

ax = Axes3D(fig)
surf = ax.plot_surface(w, b, mse, rstride=1, cstride=1, cmap='rainbow')

# 设置下标

ax.set_xlabel('w')
ax.set_ylabel('b')
ax.set_zlabel('Loss')

# 设置颜色条
fig.colorbar(surf, shrink=0.5, aspect=5)
plt.show()

手写数字模型：

运行手写数字识别基础模型

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梯度下降算法：

import numpy as np
import matplotlib.pyplot as plt

x_data = [1.0, 2.0, 3.0]
y_data = [2.0, 4.0, 6.0]

w = 1.0


def forward(x):
    return x * w


def cost(xs, ys):
    cost = 0
    for x, y in zip(xs, ys):
        y_pred = forward(x)
        loss = (y_pred - y) ** 2
        cost += loss
    return cost / len(xs)


def gradient(xs, ys):
    grad = 0
    for x, y in zip(xs, ys):
        grad += 2 * x * (x * w - y)
        return grad / len(xs)


cost_list = []
epoch_list = []

print("predict (before trainning)", 4, forward(4))

for epoch in range(100):
    epoch_list.append(epoch)
    cost_val = cost(x_data, y_data)
    cost_list.append(cost_val)
    gradient_val = gradient(x_data, y_data)
    w -= 0.01 * gradient_val
    print("Epoch:", epoch, "w=", w, "loss = ", cost_val)

print("Prediction (after trainning)", 4, forward(4))

plt.plot(epoch_list, cost_list)
plt.xlabel("epoch")
plt.ylabel("cost")
plt.show()

随机梯度下降

import numpy as np
import matplotlib.pyplot as plt

x_data = [1.0, 2.0, 3.0]
y_data = [2.0, 4.0, 6.0]

w = 1.0


def forward(x):
    return x * w


def loss(x, y):
    y_pred = forward(x)
    return (y_pred - y) ** 2


def gradient(x, y):
    y_pred = forward(x)
    return 2 * x * (y_pred - y)


lost_list = []
epoch_list = []

print("predict (before trainning)", 4, forward(4))

for epoch in range(100):
    epoch_list.append(epoch)
    for x, y in zip(x_data, y_data):
        loss_val = loss(x, y)
        grad = gradient(x, y)
        w -= 0.01 * grad
    print("Epoch:", epoch, "w=", w, "loss = ", loss_val)
    lost_list.append(loss_val)

print("Prediction (after trainning)", 4, forward(4))
plt.plot(epoch_list, lost_list)
plt.xlabel("Epoch")
plt.ylabel("Loss")
plt.show()

反向传播

import torch

x_data = [1.0, 2.0, 3.0]
y_data = [2.0, 4.0, 6.0]

w = torch.tensor([1.0], requires_grad=True)


def forward(x):
    return x * w


def loss(x, y):
    y_pred = forward(x)
    return (y_pred - y) ** 2


print("Predict  (before)", 4, forward(4).item())

for epoch in range(100):
    for x, y in zip(x_data, y_data):
        l = loss(x, y)
        l.backward()
        print("\t grad:", x, y, w.grad.item())
        w.data = w.data - 0.01 * w.grad.data
        w.grad.data.zero_()

    print('progress:', epoch, l.item())
print("Predict (after):", 4, forward(4).item())

反向传播 二次方程

import  torch
import matplotlib.pyplot as plt
x_data = [1.0, 2.0, 3.0]
y_data = [2.0, 4.0, 6.0]

w1 = torch.tensor([1.0], requires_grad=True)
w2 = torch.tensor([1.0], requires_grad=True)
b = torch.tensor([1.0], requires_grad=True)


def forward(x):
    return (x**2) * w1 + x * w2 +b

def loss(x,y):
    y_pred = forward(x)
    return (y_pred - y) ** 2

cost_list = []
epoch_list = []

print("Predict (before):", 4 , forward(4).item())

for epoch in range(100):
    epoch_list.append(epoch)
    for x, y in zip(x_data,y_data):
        l= loss(x,y)
        l.backward()
        print("\t grad:",x,y,w1.grad.item(),w2.grad.item(),b.grad.item())
        w1.data = w1.data - 0.01 * w1.grad.data
        w1.grad.data.zero_()
        w2.data = w2.data - 0.01 * w2.grad.data
        w2.grad.data.zero_()
        b.data = b.data - 0.01 * b.grad.data
        b.grad.data.zero_()
    print('Progress:', epoch, l.item())
    cost_list.append(l.item())
print("Predict (after)", 4, forward(4).item())
plt.plot(epoch_list, cost_list)
plt.xlabel("epoch")
plt.ylabel("cost")
plt.show()

线性模型

训练的过程就是前馈（计算方程 ），反馈（算梯度）以及更新权重

继承Module的类 会自动有一个反馈backward的过程 所以LinearModel类只需要init（）和forward（）方法即可

实现回归方程的通用四步骤

1. 准备数据集
2. 用类设计模型
3. 构造损失（量化的指标）和优化器（backward）
4. 训练循环

import torch
import torch.nn as nn
import torch.optim as optim
import matplotlib.pyplot as plt

x_data = torch.tensor([[1.0],[2.0],[3.0]])
y_data = torch.tensor([[2.0],[4.0],[6.0]])

class LinearModel(nn.Module):
    def  __init__(self):
        super(LinearModel,self).__init__()
        self.linear = nn.Linear(1,1)

    def forward(self, x):
        y_pred = self.linear(x)
        return y_pred


model = LinearModel()
criterion = nn.MSELoss(size_average=False)
optimizer = optim.SGD(model.parameters(),lr=0.01)

epoch_list=[]
loss_list=[]

for epoch in range(100):
    y_pred = model(x_data)
    loss = criterion(y_pred,y_data)
    print(epoch,loss)
    epoch_list.append(epoch)
    loss_list.append(loss.item())

    optimizer.zero_grad()
    loss.backward()
    optimizer.step()

print('w= ',model.linear.weight.item())
print('b= ',model.linear.bias.item())


x_test = torch.tensor([4.0])
y_test = model(x_test)
print('y_pred= ',y_test.item())

plt.plot(epoch_list, loss_list)
plt.xlabel("Epoch")
plt.ylabel("Loss")
plt.show()

SGD 图像识别

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逻辑回归

torchvision包里面自带数据集 MINIST CIFAR10

饱和函数就是 导函数是一条凸函数的 类似正态分布的图像

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.view（）等于numpy里面的reshape

import matplotlib.pyplot as plt
import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.optim as optim
import numpy as np

x_data = torch.Tensor([[1.0], [2.0], [3.0]])
y_data = torch.Tensor([[0], [0], [1]])


class LogisticRegressionModel(nn.Module):
    def __init__(self):
        super(LogisticRegressionModel, self).__init__()
        self.linear = nn.Linear(1, 1)

    def forward(self, x):
        y_pred = F.sigmoid(self.linear(x))
        return y_pred


model = LogisticRegressionModel()

criterion = nn.BCELoss(size_average=False)
optimizer = optim.SGD(model.parameters(), lr=0.01)

for epoch in range(1000):
    y_pred = model(x_data)
    loss = criterion(y_pred, y_data)

    optimizer.zero_grad()
    loss.backward()
    optimizer.step()

x = np.linspace(0, 10, 200)
x_t = torch.Tensor(x).view(200, 1)
y_t = model(x_t)
y = y_t.data.numpy()

plt.plot(x, y)
plt.plot([0, 10], [0.5, 0.5], c='r')
plt.xlabel("Hours")
plt.ylabel("Prob of Pass")
plt.grid()
plt.show()

多维数据的输入

pytorch里面只限定了数据的列数 不限定数据的行数

通过引入sigmod函数将8维的空间转化为1维的函数（起到了非线性变换的作用）

import numpy as np
import torch
import torch.nn as nn
import torch.optim as optim

xy = np.loadtxt("./diabetes.csv.gz", delimiter=",", dtype=np.float32)
x_data = torch.from_numpy(xy[:, :-1])
y_data = torch.from_numpy(xy[:, [-1]])


class Model(nn.Module):
    def __init__(self):
        super(Model, self).__init__()
        self.linear1 = nn.Linear(8, 6)
        self.linear2 = nn.Linear(6, 4)
        self.linear3 = nn.Linear(4, 1)
        self.sigmod = nn.Sigmoid()


    def forward(self, x):
        x = self.sigmod(self.linear1(x))
        x = self.sigmod(self.linear2(x))
        x = self.sigmod(self.linear3(x))
        return x

model = Model()
criterion = nn.BCELoss(reduction='mean')
optimizer = optim.SGD(model.parameters(),lr=0.1)
for epoch in range(1000):
    y_pred = model(x_data)
    loss = criterion(y_pred,y_data)
    print(epoch, loss.item())

    optimizer.zero_grad()
    loss.backward()
    optimizer.step()
print('----------Number1------------')
print(model.linear1.weight.data)
print(model.linear1.bias.data)
print('----------Number2------------')
print(model.linear2.weight.data)
print(model.linear2.bias.data)
print('----------Number3------------')
print(model.linear3.weight.data)
print(model.linear3.bias.data)

Titanic数据处理 多维数据未实现

import torch
import numpy as np
from torch.utils.data import Dataset
from torch.utils.data import DataLoader
import pandas as pd


class TitanicDataSet(Dataset):
    def __init__(self, filePath):
        xy = np.loadtxt(filePath, delimiter=',', dtype=np.float32)
        self.len = xy.shape[0]
        self.x_data = torch.from_numpy(xy[1:, [0,2-12]])
        self.y_data = torch.from_numpy(xy[1:, [1]])

    def __getitem__(self, index):
        return self.x_data[index], self.y_data[index]

    def __len__(self):
        return self.len
#
# x_data, y_data = TitanicDataSet('./titanic/train.csv')
# print(x_data)
# print("--------")
# print(y_data)


all_df = pd.read_csv(r'./titanic/train.csv',encoding="ISO-8859-1", low_memory=False)
print(all_df)
#把需要的列放进一个列表中，表示选中这些列, 拿到我们需要的数据集
cols = ['Survived', 'Name', 'Pclass', 'Sex', 'Age', 'SibSp', 'Parch', 'Fare', 'Embarked']
data= all_df[cols].drop(['Name'], axis=1)
data.head()
# 将性别为female用0代替， male用1代替ß
dict_sex = {'female': 0, 'male': 1}
data['Sex'] = data['Sex'].map(dict_sex)

# 登船口也和性别处理方法一样
dict_embarked = {'S': 0, 'C': 1, 'Q': 2}
data['Embarked'] = data['Embarked'].map(dict_embarked)
#该方法可以计算数据中分别有多少个空值
print(data.isnull().sum())
#因为有很多的年龄为空值， 所以我们用这个方法可以用年龄的平均值填充空位
age_mean = data['Age'].mean()
data['Age'] = data['Age'].fillna(age_mean)
#填充fare
fare_mean = data['Fare'].mean()
data['Fare'] = data['Fare'].fillna(fare_mean)
#因为哪个登船口上船对生还率影响不大, 所以用1登船口填充
data['Embarked'] = data['Embarked'].fillna(1)

print(data)

多分类问题（softmax分类器）

import torch

from torchvision import datasets
from torchvision import transforms
from torch.utils.data import DataLoader

import torch.nn as nn
import torch.nn.functional as F
import torch.optim as optim

# prepare dataset

batch_size = 64
transform = transforms.Compose([transforms.ToTensor(), transforms.Normalize((0.1307,), (0.3081,))])

train_dataset = datasets.MNIST(root='./dataset/mnist/', train=True, download=True, transform=transform)
test_dataset = datasets.MNIST(root='./dataset/mnist/', train=False, download=True, transform=transform)
train_loader = DataLoader(train_dataset, shuffle=True, batch_size=batch_size)
test_loader = DataLoader(test_dataset, shuffle=True, batch_size=batch_size)


# design model
class Model(nn.Module):
    def __init__(self):
        super(Model, self).__init__()
        self.l1 = nn.Linear(784, 512)
        self.l2 = nn.Linear(512, 256)
        self.l3 = nn.Linear(256, 128)
        self.l4 = nn.Linear(128, 64)
        self.l5 = nn.Linear(64, 10)

    def forward(self, x):
        x = x.view(-1, 784)
        x = F.relu(self.l1(x))
        x = F.relu(self.l2(x))
        x = F.relu(self.l3(x))
        x = F.relu(self.l4(x))
        x = self.l5(x)
        return x


model = Model()

criterion = nn.CrossEntropyLoss()
optimizer = optim.SGD(model.parameters(), lr=0.01, momentum=0.5)


# training cycle forward ,backward ,update

def train(epoch):
    running_loss = 0.0
    for batch_idx, data in enumerate(train_loader, 0):
        # 获取一个批次的数据和标签
        inputs, target = data
        optimizer.zero_grad()

        outputs = model(inputs)

        # 交叉墒的代价函数outputs （64，10）target（64）
        loss = criterion(outputs, target)
        loss.backward()
        optimizer.step()
        running_loss += loss.item()
        if batch_idx % 300 == 299:
            print('[epoch : %d, batch_idx : %5d  loss: %.3f ' % (epoch + 1, batch_idx + 1, running_loss / 300))
            running_loss = 0.0


def test():
    correct = 0
    total = 0

    with torch.no_grad():
        for data in test_loader:
            inputs, labels = data
            outputs = model(inputs)
            _, predicted = torch.max(outputs.data, dim=1)
            total += labels.size(0)
            correct += (predicted == labels).sum().item()

    print('accuracy on test set: %d %% ' % (100 * correct / total))


for epoch in range(10):
    train(epoch)
    test()

卷积神经网络 CNN

import torch
import torch.nn as nn
from torchvision import transforms
from torchvision import datasets
from torch.utils.data import DataLoader

import torch.nn.functional as F
import torch.optim as optim
import time

# 准备数据

batch_size = 64
transform = transforms.Compose([transforms.ToTensor(), transforms.Normalize((0.1307,), (0.3081,))])

train_dataset = datasets.MNIST(root='../dataset/mnist/', train=True, download=True, transform=transform)
train_loader = DataLoader(train_dataset, shuffle=True, batch_size=batch_size)

test_dataset = datasets.MNIST(root='../dataset/mnist/', train=False, download=True, transform=transform)

test_loader = DataLoader(test_dataset, shuffle=False, batch_size=batch_size)


# design model using class
class Net(nn.Module):
    def __init__(self):
        super(Net, self).__init__()
        self.conv1 = nn.Conv2d(1, 10, kernel_size=5)
        self.conv2 = nn.Conv2d(10, 20, kernel_size=5)
        self.pooling = nn.MaxPool2d(2)
        self.fc = nn.Linear(320, 10)

    def forward(self, x):
        # flatten data from (n,1,28,28) to (n , 784)
        batch_size = x.size(0)
        x = F.relu(self.pooling(self.conv1(x)))
        x = F.relu(self.pooling(self.conv2(x)))
        x = x.view(batch_size, -1)
        x = self.fc(x)
        return x


model = Net()

# construct loss and optimizer
criterion = torch.nn.CrossEntropyLoss()
optimizer = optim.SGD(model.parameters(), lr=0.01, momentum=0.5)


# trainning cycle forward, backward, update

def train(epoch):
    running_loss = 0.0
    for batch_idx, data in enumerate(train_loader, 0):
        inputs, target = data
        optimizer.zero_grad()

        outputs = model(inputs)
        loss = criterion(outputs, target)
        loss.backward()
        optimizer.step()

        running_loss += loss.item()
        if batch_idx % 300 == 299:
            print('[%d, %5d] loss : %.3f' % (epoch + 1, batch_idx + 1, running_loss / 300))
            running_loss = 0.0


def test():
    correct = 0
    total = 0
    with torch.no_grad():
        for data in test_loader:
            images, labels = data
            outputs = model(images)
            _, predicted = torch.max(outputs.data, dim=1)
            total += labels.size(0)
            correct += (predicted == labels).sum().item()
    print('accuracy on test set : %d %% ' % (100 * correct / total))


torch.cuda.synchronize()
start = time.time()
for epoch in range(10):
    train(epoch)
    test()
torch.cuda.synchronize()

end = time.time()
time_elapsed = end - start
print('Trainning complete in {:.0f}m {:.0f}s'.format(time_elapsed // 60, time_elapsed % 60))

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CNN用cuda实现

import torch
import torch.nn as nn
from torchvision import transforms
from torchvision import datasets
from torch.utils.data import DataLoader

import torch.nn.functional as F
import torch.optim as optim
import time

# 准备数据

batch_size = 64
transform = transforms.Compose([transforms.ToTensor(), transforms.Normalize((0.1307,), (0.3081,))])

train_dataset = datasets.MNIST(root='../dataset/mnist/', train=True, download=True, transform=transform)
train_loader = DataLoader(train_dataset, shuffle=True, batch_size=batch_size)
test_dataset = datasets.MNIST(root='../dataset/mnist/', train=False, download=True, transform=transform)
test_loader = DataLoader(test_dataset, shuffle=False, batch_size=batch_size)


# design model using class
class Net(nn.Module):
    def __init__(self):
        super(Net, self).__init__()
        self.conv1 = nn.Conv2d(1, 10, kernel_size=5)
        self.conv2 = nn.Conv2d(10, 20, kernel_size=5)
        self.pooling = nn.MaxPool2d(2)
        self.fc = nn.Linear(320, 10)

    def forward(self, x):
        # flatten data from (n,1,28,28) to (n , 784)
        batch_size = x.size(0)
        x = F.relu(self.pooling(self.conv1(x)))
        x = F.relu(self.pooling(self.conv2(x)))
        x = x.view(batch_size, -1)
        x = self.fc(x)
        return x


model = Net()
device = torch.device('cuda:0' if torch.cuda.is_available() else 'cpu')
model.to(device)
# construct loss and optimizer
criterion = torch.nn.CrossEntropyLoss()
optimizer = optim.SGD(model.parameters(), lr=0.01, momentum=0.5)
# trainning cycle forward, backward, update

def train(epoch):
    running_loss = 0.0
    for batch_idx, data in enumerate(train_loader, 0):
        inputs, target = data
        inputs, target = inputs.to(device), target.to(device)
        optimizer.zero_grad()

        outputs = model(inputs)
        loss = criterion(outputs, target)
        loss.backward()
        optimizer.step()

        running_loss += loss.item()
        if batch_idx % 300 == 299:
            print('[%d, %5d] loss : %.3f' % (epoch + 1, batch_idx + 1, running_loss / 300))
            running_loss = 0.0


def test():
    correct = 0
    total = 0
    with torch.no_grad():
        for data in test_loader:
            images, labels = data
            images, labels = images.to(device), labels.to(device)
            outputs = model(images)
            _, predicted = torch.max(outputs.data, dim=1)
            total += labels.size(0)
            correct += (predicted == labels).sum().item()
    print('accuracy on test set : %d %% ' % (100 * correct / total))


torch.cuda.synchronize()
start = time.time()
for epoch in range(10):
    train(epoch)
    test()
torch.cuda.synchronize()

end = time.time()
time_elapsed = end - start
print('Trainning complete in {:.0f}m {:.0f}s'.format(time_elapsed // 60, time_elapsed % 60))

高级CNN

import torch
import torch.nn as nn
from torchvision import transforms
from torchvision import datasets
from torch.utils.data import DataLoader
import torch.nn.functional as F
import torch.optim as optim
import time
import matplotlib.pyplot as plt

# prepare dataset

batch_size = 64
transform = transforms.Compose([transforms.ToTensor(), transforms.Normalize((0.1307,), (0.3081,))])

train_dataset = datasets.MNIST(root='../dataset/mnist/', train=True, download=True, transform=transform)
train_loader = DataLoader(train_dataset, shuffle=True, batch_size=batch_size)
test_dataset = datasets.MNIST(root='../dataset/mnist/', train=False, download=True, transform=transform)
test_loader = DataLoader(test_dataset, shuffle=False, batch_size=batch_size)


# design model using class
class InceptionA(nn.Module):
    def __init__(self, in_channels):
        super(InceptionA, self).__init__()
        self.branchx1 = nn.Conv2d(in_channels, 16, kernel_size=1)

        self.branch5x5_1 = nn.Conv2d(in_channels, 16, kernel_size=1)
        self.branch5x5_2 = nn.Conv2d(16, 24, kernel_size=5, padding=2)

        self.branch3x3_1 = nn.Conv2d(in_channels, 16, kernel_size=1)
        self.branch3x3_2 = nn.Conv2d(16, 24, kernel_size=3, padding=1)
        self.branch3x3_3 = nn.Conv2d(24, 24, kernel_size=3, padding=1)

        self.branch_pool = nn.Conv2d(in_channels, 24, kernel_size=1)

    def forward(self, x):
        branch1x1 = self.branchx1(x)

        branch5x5 = self.branch5x5_1(x)
        branch5x5 = self.branch5x5_2(branch5x5)

        branch3x3 = self.branch3x3_1(x)
        branch3x3 = self.branch3x3_2(branch3x3)
        branch3x3 = self.branch3x3_3(branch3x3)

        branch_pool = F.avg_pool2d(x, kernel_size=3, stride=1, padding=1)
        branch_pool = self.branch_pool(branch_pool)

        output = [branch1x1, branch5x5, branch3x3, branch_pool]
        return torch.cat(output, dim=1)


class Net(nn.Module):
    def __init__(self):
        super(Net, self).__init__()
        self.conv1 = nn.Conv2d(1, 10, kernel_size=5)
        self.conv2 = nn.Conv2d(88, 20, kernel_size=5)

        self.incep1 = InceptionA(in_channels=10)
        self.incep2 = InceptionA(in_channels=20)

        self.mp = nn.MaxPool2d(2)
        self.fc = nn.Linear(1408, 10)

    def forward(self, x):
        in_size = x.size(0)
        x = F.relu(self.mp(self.conv1(x)))
        x = self.incep1(x)
        x = F.relu(self.mp(self.conv2(x)))
        x = self.incep2(x)
        x = x.view(in_size, -1)
        x = self.fc(x)
        return x


model = Net()
device = torch.device('cuda:0' if torch.cuda.is_available() else 'cpu')
model.to(device)

# construct loss and optimizer
criterion = torch.nn.CrossEntropyLoss()
optimizer = optim.SGD(model.parameters(), lr=0.01, momentum=0.5)


# training cycle forward, backward,update

def train(epoch):
    running_loss = 0.0
    for batch_idx, data in enumerate(train_loader, 0):
        inputs, target = data
        inputs, target = inputs.to(device), target.to(device)

        optimizer.zero_grad()
        outputs = model(inputs)
        loss = criterion(outputs, target)
        loss.backward()
        optimizer.step()

        running_loss += loss.item()
        if batch_idx % 300 == 299:
            print('[%d , %5d]  loss : %.3f' % (epoch + 1, batch_idx + 1, running_loss / 300))
            running_loss = 0.0


accuracy = []
def test():
    correct = 0
    total = 0
    with torch.no_grad():
        for data in test_loader:
            images, labels = data
            images, labels = images.to(device), labels.to(device)
            outputs = model(images)
            _, predicted = torch.max(outputs.data, dim=1)
            total += labels.size(0)
            correct += (predicted == labels).sum().item()
    print('accuracy on test set:  %d %%' % (100 * correct / total))
    accuracy.append(100 * correct / total)


torch.cuda.synchronize()
start = time.time()
for epoch in range(10):
    train(epoch)
    test()
torch.cuda.synchronize()
end = time.time()

time_elapsed = end - start
print('Training complete in {:.0f}m {:.0f}s'.format(time_elapsed // 60, time_elapsed % 60))

plt.plot(range(10), accuracy)
plt.xlabel("epoch")
plt.ylabel("accuracy")
plt.grid()
plt.show()
print("done")

import torch
import torch.nn as nn
from torchvision import transforms
from torchvision import datasets
from torch.utils.data import DataLoader
import torch.nn.functional as F
import torch.optim as optim
import time
import matplotlib.pyplot as plt

# prepare dataset

batch_size = 64
transform = transforms.Compose([transforms.ToTensor(), transforms.Normalize((0.1307,), (0.3081,))])

train_dataset = datasets.MNIST(root='../dataset/mnist/', train=True, download=True, transform=transform)
train_loader = DataLoader(train_dataset, shuffle=True, batch_size=batch_size)
test_dataset = datasets.MNIST(root='../dataset/mnist/', train=False, download=True, transform=transform)
test_loader = DataLoader(test_dataset, shuffle=False, batch_size=batch_size)


# design model using class
class ResidualBlock(nn.Module):
    def __init__(self, channels):
        super(ResidualBlock, self).__init__()
        self.channels = channels
        self.conv1 = nn.Conv2d(channels, channels, kernel_size=3, padding=1)
        self.conv2 = nn.Conv2d(channels, channels, kernel_size=3, padding=1)

    def forward(self, x):
        y = F.relu(self.conv1(x))
        y == self.conv2(y)
        return F.relu(x + y)


class Net(nn.Module):
    def __init__(self):
        super(Net, self).__init__()
        self.conv1 = nn.Conv2d(1, 16, kernel_size=5)
        self.conv2 = nn.Conv2d(16, 32, kernel_size=5)
        self.mp = nn.MaxPool2d(2)


        self.rblock1 = ResidualBlock(16)
        self.rblock2 = ResidualBlock(32)

        self.fc = nn.Linear(512, 10)

    def forward(self, x):
        in_size = x.size(0)
        x = self.mp(F.relu(self.conv1(x)))
        x = self.rblock1(x)
        x = self.mp(F.relu(self.conv2(x)))
        x = self.rblock2(x)
        x = x.view(in_size, -1)
        x = self.fc(x)
        return x


model = Net()
device = torch.device('cuda:0' if torch.cuda.is_available() else 'cpu')
model.to(device)

# construct loss and optimizer
criterion = torch.nn.CrossEntropyLoss()
optimizer = optim.SGD(model.parameters(), lr=0.01, momentum=0.5)


# training cycle forward, backward,update

def train(epoch):
    running_loss = 0.0
    for batch_idx, data in enumerate(train_loader, 0):
        inputs, target = data
        inputs, target = inputs.to(device), target.to(device)

        optimizer.zero_grad()
        outputs = model(inputs)
        loss = criterion(outputs, target)
        loss.backward()
        optimizer.step()

        running_loss += loss.item()
        if batch_idx % 300 == 299:
            print('[%d , %5d]  loss : %.3f' % (epoch + 1, batch_idx + 1, running_loss / 300))
            running_loss = 0.0


accuracy = []


def test():
    correct = 0
    total = 0
    with torch.no_grad():
        for data in test_loader:
            images, labels = data
            images, labels = images.to(device), labels.to(device)
            outputs = model(images)
            _, predicted = torch.max(outputs.data, dim=1)
            total += labels.size(0)
            correct += (predicted == labels).sum().item()
    print('accuracy on test set:  %d %%' % (100 * correct / total))
    accuracy.append(100 * correct / total)


torch.cuda.synchronize()
start = time.time()
for epoch in range(10):
    train(epoch)
    test()
torch.cuda.synchronize()
end = time.time()

time_elapsed = end - start
print('Training complete in {:.0f}m {:.0f}s'.format(time_elapsed // 60, time_elapsed % 60))

plt.plot(range(10), accuracy)
plt.xlabel("epoch")
plt.ylabel("accuracy")
plt.grid()
plt.show()
print("done")

RNN

Dense Deep 要拿到之前若干天钱的数据预测今天是否下雨

卷积层的输入和输出 只和通道还有卷积核的大小有关

全连接层和你变化的数据有关 卷积层的运算看起来复杂 但实际上消费并不高

卷积核 整个图像共享

RNN是一种专门处理带有序列模式的数据 其中使用权重共享 来减少需要训练的权重数量

RNNCell（是同一个线性层） ==Linear h0是先验知识

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先根据字符构造词典

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独热编码 缺点： 高纬度 分散 硬编码

RNN GRU LTSM

手写循环实现RNN 便于理解RNN的工作流程

import torch

# "需要:初始化h0,输入序列"
batch_size = 1
input_size = 4
hidden_size = 2
seq_len = 3

cell = torch.nn.RNNCell(input_size=input_size, hidden_size=hidden_size)

dataset = torch.randn(seq_len, batch_size, input_size)  # 构造输入序列
hidden = torch.zeros(batch_size, hidden_size)  # 构造全是0的隐层,即初始化h0

for idex, input in enumerate(dataset):
    print('=' * 20, idex, '=' * 20)
    print('Input size:', input.shape)
    hidden = cell(input, hidden)
    print('outputs size:', hidden.shape)
    print('hidden:', hidden)

使用torch.nn.RNN系统自带的调用

import torch

batch_size = 1
input_size = 4
hidden_size = 2
seq_len = 3
num_layers = 2

cell = torch.nn.RNN(input_size=input_size, hidden_size=hidden_size, num_layers=num_layers)
inputs = torch.randn(seq_len, batch_size, input_size)
hidden = torch.zeros(num_layers, batch_size, hidden_size)

out, hidden = cell(inputs, hidden)

print('output size:', out.shape)
print('out:', out)
print('hidden size:', hidden.shape)
print('hidden:', hidden)

例子 通过RNNCell学习序列“hello”→“ohlol”转换的规律

1. 构建字典（建立character和index之间的映射关系），通过indices编码得到one-hot向量

2. 确定RNN的输出：一个四维向量，再分类器来实现文本序列的重新排列

   ​ ·```python

   import torch
   import torch.nn as nn
   import torch.optim as optim
   
   input_size = 4
   hidden_size = 4
   batch_size = 1
   
   # prepare data
   idx2char = ['e', 'h', 'l', 'o']
   x_data = [1, 0, 2, 2, 3]  # hello 输入
   y_data = [3, 1, 2, 3, 2]  # ohlol 目标
   
   one_hot_lookup = [[1, 0, 0, 0],
                     [0, 1, 0, 0],
                     [0, 0, 1, 0],
                     [0, 0, 0, 1]]  # 分别对应0，1，2，3即e,h,l,o 独热编码
   
   x_one_hot = [one_hot_lookup[x] for x in x_data]
   
   inputs = torch.Tensor(x_one_hot).view(-1, batch_size, input_size)  # -1即seqLen
   labels = torch.LongTensor(y_data).view(-1, 1)  # (seqLen,1)
   
   
   # define model
   class Model(nn.Module):
       def __init__(self, input_size, hidden_size, batch_size):
           super(Model, self).__init__()
           self.input_size = input_size
           self.hidden_size = hidden_size
           self.batch_size = batch_size
           self.rnncell = nn.RNNCell(input_size=self.input_size,
                                     hidden_size=self.hidden_size)
   
       def forward(self, input, hidden):
           hidden = self.rnncell(input, hidden)
           return hidden
   
       def init_hidden(self):
           return torch.zeros(self.batch_size, self.hidden_size)
   
   
   model = Model(input_size, hidden_size, batch_size)
   
   # loss & optimizer
   criterion = nn.CrossEntropyLoss()
   optimizer = optim.Adam(model.parameters(), lr=0.1)
   
   # training cycle
   for epoch in range(15):
       loss = 0
       optimizer.zero_grad()
       hidden = model.init_hidden()  # h0
       print('predicted string:', end='')
       for input, label in zip(inputs, labels):
           hidden = model(input, hidden)
           loss += criterion(hidden, label)
           _, idx = hidden.max(dim=1)  # hidden是4维的，分别表示e,h,l,o的概率值
           print(idx2char[idx.item()], end='')
   
       loss.backward()
       optimizer.step()
       print(',epoch [%d/15] loss = %.4lf' % (epoch + 1, loss.item()))
   

实现结果：

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One-hot矩阵是high-dimension、sparse，hardcoded的，通过Embedding将one-hot稀疏矩阵映射成低维、稠密的矩阵

为什么要使用Embedding

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import torch
import torch.nn as nn
import torch.optim as optim

num_class = 4  # 4个类别，
input_size = 4  # 输入维度
hidden_size = 8  # 隐层输出维度，有8个隐层
embedding_size = 10  # 嵌入到10维空间
num_layers = 2  # 2层的RNN
batch_size = 1
seq_len = 5  # 序列长度5

# prepare data
idx2char = ['e', 'h', 'l', 'o']
x_data = [[1, 0, 2, 2, 3]]  # (batch, seq_len) list
y_data = [3, 1, 2, 3, 2]  # ohlol

inputs = torch.LongTensor(x_data)
labels = torch.LongTensor(y_data)


# define model
class Model(nn.Module):
    def __init__(self):
        super(Model, self).__init__()
        self.emb = nn.Embedding(input_size, embedding_size)
        self.rnn = nn.RNN(input_size=embedding_size,
                          hidden_size=hidden_size,
                          num_layers=num_layers,
                          batch_first=True)
        self.fc = nn.Linear(hidden_size, num_class)

    def forward(self, x):
        hidden = torch.zeros(num_layers, x.size(0), hidden_size)
        x = self.emb(x)
        x, _ = self.rnn(x, hidden)
        x = self.fc(x)
        return x.view(-1, num_class)


model = Model()

# loss & optimizer
criterion = nn.CrossEntropyLoss()
optimizer = optim.Adam(model.parameters(), lr=0.05)

# training cycle
for epoch in range(15):
    optimizer.zero_grad()
    outputs = model(inputs)
    loss = criterion(outputs, labels)
    loss.backward()
    optimizer.step()

    print('outputs:', outputs)
    _, idx = outputs.max(dim=1)
    idx = idx.data.numpy()  # reshape to numpy
    print('idx', idx)
    print('Pridected:', ''.join([idx2char[x] for x in idx]), end='')  # end是不自动换行，''.join是连接字符串数组
    print(',Epoch [%d/15] loss = %.3f' % (epoch + 1, loss.item()))

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RNN Classifier 测试名字归属哪个国家拼写

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先通过嵌入层 变成地位稠密的响亮变成独热编码

处理自然语言常用的方法以及流程

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# 引入torch
import torch
# 引入time计时
import time
# 引入math数学函数
import math
# 引入numpy
import numpy as np
# 引入plt
import matplotlib.pyplot as plt
# 从torch的工具的数据引入数据集，数据加载器
from torch.utils.data import Dataset, DataLoader
# 从torch的神经网络的数据的rnn中引入包装填充好的序列。作用是将填充的pad去掉，然后根据序列的长短进行排序
from torch.nn.utils.rnn import pack_padded_sequence
# 引入gzip 压缩文件
import gzip
# 引入csv模块
import csv

# 隐层数是100
HIDDEN_SIZE = 100
# batch的大小时256
BATCH_SIZE = 256
# 应用2层的GRU
N_LAYER = 2
# 循环100
N_EPOCHS = 100
# 字符数量时128
N_CHARS = 128
# 不使用GPU
USE_GPU = True


# 定义名字数据集的类，继承自数据集

class NameDataset(Dataset):
    # 自身初始化，是训练集为真
    def __init__(self, is_train_set=True):
        # 文件名是训练集。如果训练为真，否则是测试集
        filename = 'names_train.csv.gz' if is_train_set else 'names_test.csv.gz'
        # 用gzip打开文件名，操作text文本的时候使用'rt'，作为f
        with gzip.open(filename, 'rt') as f:
            # 阅读器是用csv的阅读器阅读文件
            reader = csv.reader(f)
            # 将文件设成一个列表
            rows = list(reader)
        # 自身名字是文件的第一列都是名字，提取第一列，对于r在rs中时
        self.names = [row[0] for row in rows]
        # 长度是名字的长度
        self.len = len(self.names)
        # 国家是第二列
        self.countries = [row[1] for row in rows]
        # 将国家变成集合，去除重复的元素，然后进行排序，然后接着再变回列表
        self.country_list = list(sorted(set(self.countries)))
        # 得到国家的词典，将列表转化成词典(有索引)
        self.country_dict = self.getCountryDict()
        # 长度是国家的长度
        self.country_num = len(self.country_list)

    # 定义 获得项目类,提供索引访问，自身，索引
    def __getitem__(self, index):
        # 返回 带索引的名字，带索引的国家，代入，得到带国家的词典
        return self.names[index], self.country_dict[self.countries[index]]

    # 定义长度
    def __len__(self):
        # 返回长度
        return self.len

    # 定义获得国家词典
    def getCountryDict(self):
        # 现设一个空字典
        country_dict = dict()
        # idx表示进行多少次的迭代，country_name是国家名，用列举的方法将国家列表的数据提取出来，从0开始
        for idx, country_name in enumerate(self.country_list, 0):
            # 构造键值对，将国家名代入国家列表中等于1，2，3.
            country_dict[country_name] = idx
        # 返回国家列表
        return country_dict

    # 定义 索引返回国家字符串，自身索引
    def idx2country(self, index):
        # 返回 自身，将索引代入国家列表得到字符串
        return self.country_list[index]

    # 获得国家数量
    def getCountriesNum(self):
        # 返回自身国家数量
        return self.country_num


# 将训练集为真，代入名字数据集模型中得到训练集
trainset = NameDataset(is_train_set=True)
# 将训练集，batch的大小等于batch的大小，shuffle为真将数据打乱。代入到数据加载器中。得到训练加载器
trainloader = DataLoader(trainset, batch_size=BATCH_SIZE, shuffle=True)
# 将训练集为假，代入名字数据集模型中得到测试集
testset = NameDataset(is_train_set=False)
# 将测试集，batch的大小等于batch的大小，shuffle为假不把数据打乱。代入到数据加载器中。得到测试加载器
testloader = DataLoader(testset, batch_size=BATCH_SIZE, shuffle=False)
# 训练集的获得国家数量得到国家数量
N_COUNTRY = trainset.getCountriesNum()


# 创建tensor
def create_tensor(tensor):
    # 如果使用GPU
    if USE_GPU:
        # 使用第一个GPU代入到设置，得到设置
        device = torch.device("cuda:0")
        # 让张量在设置里面跑
        tensor = tensor.to(device)
    # 返回张量
    return tensor


# 将RNN分类器分成一个类，继承自Module模块
class RNNClassifier(torch.nn.Module):
    # 定义自身初始化，输入的大小，隐层的大小，输出的大小，层数是1，bidirectional为真设成双向的。
    def __init__(self, input_size, hidden_size, output_size, n_layers=1, bidirectional=True):
        # 父类初始化
        super(RNNClassifier, self).__init__()
        # 自身隐层等于隐层
        self.hidden_size = hidden_size
        # 自身层数等于层数
        self.n_layers = n_layers
        # 自身方向数量是如果bidirectional为真则是2，否则是1
        self.n_directions = 2 if bidirectional else 1
        # 将输入的大小和隐层的大小代入嵌入层得到自身嵌入层
        self.embedding = torch.nn.Embedding(input_size, hidden_size)
        # 隐层的大小是输入，隐层的大小是输出，层数，双向代入GRU模型中，得到gru
        self.gru = torch.nn.GRU(hidden_size, hidden_size, n_layers, bidirectional=bidirectional)
        # 因为是双向的，所以隐层×双向，输出的大小代入线性模型，得到,激活函数。
        self.fc = torch.nn.Linear(hidden_size * self.n_directions, output_size)

    # 初始化h0，自身batch的大小
    def _init_hidden(self, batch_size):
        # 将层数×方向数，batch的大小，隐层的大小归零，得到h0
        hidden = torch.zeros(self.n_layers * self.n_directions, batch_size, self.hidden_size)
        # 返回 创建张量的隐层
        return create_tensor(hidden)

    # 定义前馈计算，自身，输入，序列的长度
    def forward(self, input, seq_lengths):
        # 将输入进行转置，B*S--S*B
        input = input.t()
        # 输入的第二列是batch的大小
        batch_size = input.size(1)
        # 将batch的大小代入到自身初始隐层中，得到隐层的大小
        hidden = self._init_hidden(batch_size)
        # 将输入的大小代入到自身嵌入层得到嵌入层
        embedding = self.embedding(input)
        # 将嵌入层和序列的长度代入pack_padded_sequence中，先将嵌入层多余的零去掉，然后排序，打包出来，得到GRU的输入。
        gru_input = pack_padded_sequence(embedding, seq_lengths)
        # 将输入和隐层代入gru，得到输出和隐层
        output, hidden = self.gru(gru_input, hidden)
        # 如果是双向的
        if self.n_directions == 2:
            # 将隐层的最后一个和隐层的最后第二个拼接起来，按照维度为1的方向拼接起来。得到隐层
            hidden_cat = torch.cat([hidden[-1], hidden[-2]], dim=1)
        # 否则
        else:
            # 隐层就只有最后一个
            hidden_cat = hidden[-1]
        # 将隐层代入激活函数得到输出
        fc_output = self.fc(hidden_cat)
        # 返回输出
        return fc_output


# 定义名字到列表
def name2list(name):
    # 对于c在名字里，将c转变为ASC11值
    arr = [ord(c) for c in name]
    # 返回arr和长度
    return arr, len(arr)


# 定义制作张量 名字 国家
def make_tensors(names, countries):
    # 将名字代入到模型中得到ASC11值，对于名字在名字中，得到序列和长度
    sequences_and_lengths = [name2list(name) for name in names]
    # 将第一列取出来得到名字序列
    name_sequences = [sl[0] for sl in sequences_and_lengths]
    # 将第二列转换成长tensor得到序列的长度
    seq_lengths = torch.LongTensor([sl[1] for sl in sequences_and_lengths])
    # 将国家变为长整型数据
    countries = countries.long()
    # 将名字序列的长度，序列长度的最大值的长整型归零。得到序列的张量
    seq_tensor = torch.zeros(len(name_sequences), seq_lengths.max()).long()
    # 对于索引，序列和序列长度 在名字序列和名字长度中遍历，从零开始
    for idx, (seq, seq_len) in enumerate(zip(name_sequences, seq_lengths), 0):
        # 将序列变成长张量，等于序列张量，idx是索引，第1，2，3.。。。，
        #:seq_len是按照从小到大排序的序列长度，这样就将序列复制到空序列中了。
        seq_tensor[idx, :seq_len] = torch.LongTensor(seq)

    # 将序列长度按照维度为0,进行排序，下降是真，得到序列长度和索引
    seq_lengths, perm_idx = seq_lengths.sort(dim=0, descending=True)
    # 将索引赋值给序列张量
    seq_tensor = seq_tensor[perm_idx]
    # 将索引赋值给国家
    countries = countries[perm_idx]
    # 返回序列张量，序列长度，国家。创建tensor
    return create_tensor(seq_tensor), \
           create_tensor(seq_lengths), \
           create_tensor(countries)


# 定义time_since模块
def time_since(since):
    # 现在的时间减去开始的时间的到时间差
    s = time.time() - since
    # Math.floor() 返回小于或等于一个给定数字的最大整数。计算分钟数
    m = math.floor(s / 60)
    # 减去分钟数乘以60就是剩下的秒数
    s -= m * 60
    # 返回分秒
    return '%dm %ds' % (m, s)


# 定义训练模型
def trainModel():
    # 损失设为0
    total_loss = 0
    # 对于i,名字和国家在训练加载器中遍历，从1开始
    for i, (names, countries) in enumerate(trainloader, 1):
        # 将名字和国家代入到make_tensors模型中得到输入，序列长度，目标
        inputs, seq_lengths, target = make_tensors(names, countries)
        # 将输入和序列长度代入到分类器中得到输出
        output = classifier(inputs, seq_lengths.cpu())
        # 将输出和目标代入到损失标准器中得到损失
        loss = criterion(output, target)
        # 梯度归零
        optimizer.zero_grad()
        # 反向传播
        loss.backward()
        # 更新
        optimizer.step()
        # 损失标量相加得到总的损失
        total_loss += loss.item()
        # 如果i能被10整除
        if i % 10 == 0:
            # 以f开头表示在字符串内支持大括号内的python 表达式。将开始的时间代入time_since中得到分秒，循环次数，end是不换行加空格
            print(f'[{time_since(start)}]) Epoch {epoch}', end='')
            # f,i×输入的长度除以训练集的长度
            print(f'[{i * len(inputs)}/{len(trainset)}]', end='')
            # 总损失除以i×输入的长度，得到损失
            print(f'loss={total_loss / (i * len(inputs))}')
    # 返回总损失
    return total_loss


# 定义测试模型
def testModel():
    # 初始正确的为0
    correct = 0
    # 总长是测试集的长度
    total = len(testset)
    # 打印，，，
    print("evaluating trained model ...")
    # 不用梯度
    with torch.no_grad():
        # 对于i，名字和国家在测试加载器中遍历，从1开始
        for i, (name, countries) in enumerate(testloader, 1):
            # 将名字和国家代入到make_tensors模型中得到输入，序列长度，目标
            inputs, seq_lengths, target = make_tensors(name, countries)
            # 将输入和序列长度代入到分类器中得到输出
            output = classifier(inputs, seq_lengths.cpu())
            # 按照维度为1的方向，保持输出的维度为真，取输出的最大值的第二个结果，得到预测值
            pred = output.max(dim=1, keepdim=True)[1]
            # view_as将target的张量变成和pred同样形状的张量，eq是等于，预测和目标相等。标量求和
            correct += pred.eq(target.view_as(pred)).sum().item()
        # 100×正确除以错误,小数点后保留两位，得到百分比
        percent = '%.2f' % (100 * correct / total)
        # 测试集正确率
        print(f'Test set: Accuracy {correct}/{total} {percent}%')
    # 返回正确除以总数
    return correct / total


# 封装到if语句里面
if __name__ == '__main__':
    # 实例化分类器，字符的长度，隐层的大小，国家的数量，层数
    classifier = RNNClassifier(N_CHARS, HIDDEN_SIZE, N_COUNTRY, N_LAYER)
    # 如果使用GPU
    if USE_GPU:
        # 设置使用第一个GPU
        device = torch.device("cuda:0")
        # 让分类器进到设置里面跑
        classifier.to(device)
    # 标准器是交叉熵损失
    criterion = torch.nn.CrossEntropyLoss()
    # 优化器是Adam。分类器的大部分参数，学习率是0.001
    optimizer = torch.optim.Adam(classifier.parameters(), lr=0.001)
    # 开始时时间的时间
    start = time.time()
    # 打印循环次数
    print("Training for %d epochs..." % N_EPOCHS)
    # 空列表
    acc_list = []
    # 对于循环在1到循环次数中。
    for epoch in range(1, N_EPOCHS + 1):
        # 训练模型
        trainModel()
        # 测试模型
        acc = testModel()
        # 将测试结果加到列表中
        acc_list.append(acc)

# 循环，起始是1，列表长度+1是终点。步长是1
epoch = np.arange(1, len(acc_list) + 1, 1)
# 将数据变成一个矩阵
acc_list = np.array(acc_list)
# 循环，列表
plt.plot(epoch, acc_list)
# x标签
plt.xlabel('Epoch')
# y标签
plt.ylabel('Accuracy')
# 绿色
plt.grid()
# 展示
plt.show()