From 6a6cf2fedb1644b32b06ea76964a36d00c9cc517 Mon Sep 17 00:00:00 2001
From: xiazhenyu <1206064332@qq.com>
Date: Wed, 23 Mar 2022 01:18:57 +0000
Subject: [PATCH] add code of pytorch

---
 6_pytorch/fig-res-8.2.py | 238 +++++++++++++++++++++++++++++++++++++++
 6_pytorch/fig-res-8.3.py |  86 ++++++++++++++
 6_pytorch/fig-res-8.4.py |  91 +++++++++++++++
 6_pytorch/fig-res-8.5.py | 107 ++++++++++++++++++
 6_pytorch/fig-res-8.6.py | 116 +++++++++++++++++++
 5 files changed, 638 insertions(+)
 create mode 100644 6_pytorch/fig-res-8.2.py
 create mode 100644 6_pytorch/fig-res-8.3.py
 create mode 100644 6_pytorch/fig-res-8.4.py
 create mode 100644 6_pytorch/fig-res-8.5.py
 create mode 100644 6_pytorch/fig-res-8.6.py

diff --git a/6_pytorch/fig-res-8.2.py b/6_pytorch/fig-res-8.2.py
new file mode 100644
index 0000000..51310bc
--- /dev/null
+++ b/6_pytorch/fig-res-8.2.py
@@ -0,0 +1,238 @@
+import torch
+import numpy as np
+from torch import nn
+from torch.autograd import Variable
+import torch.nn.functional as F
+import matplotlib.pyplot as plt
+
+#%matplotlib inline
+np.random.seed(1)
+m = 400 # 样本数量
+N = int(m/2) # 每一类的点的个数
+D = 2 # 维度
+x = np.zeros((m, D))
+y = np.zeros((m, 1), dtype='uint8') # label 向量， 0 表示红色， 1 表示蓝色
+a = 4
+
+# 生成两类数据
+for j in range(2):
+    ix = range(N*j,N*(j+1))
+    t = np.linspace(j*3.12,(j+1)*3.12,N) + np.random.randn(N)*0.2 # theta
+    r = a*np.sin(4*t) + np.random.randn(N)*0.2 # radius
+    x[ix] = np.c_[r*np.sin(t), r*np.cos(t)]
+    y[ix] = j
+
+plt.ylabel("x2")
+plt.xlabel("x1")
+# 绘出生成的数据
+for i in range(m):
+    if y[i] == 0:
+        plt.scatter(x[i, 0], x[i, 1], marker='8',c=0, s=40, cmap=plt.cm.Spectral)
+    else:
+        plt.scatter(x[i, 0], x[i, 1], marker='^',c=1, s=40)
+plt.savefig('fig-res-8.2.pdf')
+plt.show()
+# #尝试用逻辑回归解决
+# x = torch.from_numpy(x).float()
+# y = torch.from_numpy(y).float()
+
+# w = nn.Parameter(torch.randn(2, 1))
+# b = nn.Parameter(torch.zeros(1))
+
+# # [w,b]是模型的参数； 1e-1是学习速率
+# optimizer = torch.optim.SGD([w, b], 1e-1)
+# criterion = nn.BCEWithLogitsLoss()
+# def logistic_regression(x):
+#     return torch.mm(x, w) + b
+
+
+# for e in range(100):
+#     # 模型正向计算
+#     out = logistic_regression(Variable(x))
+#     # 计算误差
+#     loss = criterion(out, Variable(y))
+#     # 误差反传和参数更新
+#     optimizer.zero_grad()
+#     loss.backward()
+#     optimizer.step()
+#     if (e + 1) % 20 == 0:
+#         print('epoch:{}, loss:{}'.format(e+1, loss.item()))
+
+
+# def plot_decision_boundary(model, x, y):
+#     # Set min and max values and give it some padding
+#     x_min, x_max = x[:, 0].min() - 1, x[:, 0].max() + 1
+#     y_min, y_max = x[:, 1].min() - 1, x[:, 1].max() + 1 
+#     h = 0.01
+#     # Generate a grid of points with distance h between them
+#     xx, yy = np.meshgrid(np.arange(x_min, x_max, h), np.arange(y_min,y_max, h))    
+
+#     # Predict the function value for the whole grid .c_ 按行连接两个矩阵，左右相加。
+#     Z = model(np.c_[xx.ravel(), yy.ravel()])
+#     Z = Z.reshape(xx.shape)
+#     # Plot the contour and training examples
+#     plt.contourf(xx, yy, Z, cmap=plt.cm.Spectral)
+#     plt.ylabel("x2")
+#     plt.xlabel("x1")
+#     plt.scatter(x[:, 0], x[:, 1], c=y.reshape(-1), s=40, cmap=plt.cm.Spectral)
+
+# def plot_logistic(x):
+#     x = Variable(torch.from_numpy(x).float())
+#     out = F.sigmoid(logistic_regression(x))
+#     out = (out > 0.5) * 1
+#     return out.data.numpy()
+
+# plot_decision_boundary(lambda x: plot_logistic(x), x.numpy(), y.numpy())
+# plt.title('logistic regression')
+# plt.savefig('fig-res-8.3.pdf')
+
+
+# # 定义两层神经网络的参数
+# w1 = nn.Parameter(torch.randn(2, 4) * 0.01) # 输入维度为2， 隐藏层神经元个数4
+# b1 = nn.Parameter(torch.zeros(4))
+# w2 = nn.Parameter(torch.randn(4, 1) * 0.01) # 隐层神经元为4， 输出单元为1
+# b2 = nn.Parameter(torch.zeros(1))
+
+# def mlp_network(x):
+#     x1 = torch.mm(x, w1) + b1
+#     x1 = F.tanh(x1) # 使用 PyTorch 自带的 tanh 激活函数
+#     x2 = torch.mm(x1, w2) + b2
+#     return x2
+
+# # 定义优化器和损失函数
+# optimizer = torch.optim.SGD([w1, w2, b1, b2], 1.)
+# criterion = nn.BCEWithLogitsLoss()
+
+# for e in range(10000):
+#     # 正向计算
+#     out = mlp_network(Variable(x))
+#     # 计算误差
+#     loss = criterion(out, Variable(y))
+#     # 计算梯度并更新权重
+#     optimizer.zero_grad()
+#     loss.backward()
+#     optimizer.step()
+#     if (e + 1) % 1000 == 0:
+#         print('epoch: {}, loss: {}'.format(e+1, loss.item()))
+
+# def plot_network(x):
+#     x = Variable(torch.from_numpy(x).float())
+#     x1 = torch.mm(x, w1) + b1
+#     x1 = F.tanh(x1)
+#     x2 = torch.mm(x1, w2) + b2
+#     out = F.sigmoid(x2)
+#     out = (out > 0.5) * 1
+#     return out.data.numpy()
+
+# plot_decision_boundary(lambda x: plot_network(x), x.numpy(), y.numpy())
+# plt.title('2 layer network')
+# plt.savefig('fig-res-8.4.pdf')
+
+# # Sequential
+# seq_net = nn.Sequential(
+#     nn.Linear(2, 4), # PyTorch 中的线性层， wx + b
+#     nn.Tanh(),
+#     nn.Linear(4, 1)
+# )
+
+# # 序列模块可以通过索引访问每一层
+# seq_net[0] # 第一层
+
+# # 打印出第一层的权重
+# w0 = seq_net[0].weight
+# print(w0)
+
+
+# # 通过 parameters 可以取得模型的参数
+# param = seq_net.parameters()
+# # 定义优化器
+# optim = torch.optim.SGD(param, 1.)
+
+# # 训练 10000 次
+# for e in range(10000):
+#     # 网络正向计算
+#     out = seq_net(Variable(x))
+#     # 计算误差
+#     loss = criterion(out, Variable(y))
+#     # 反向传播、 更新权重
+#     optim.zero_grad()
+#     loss.backward()
+#     optim.step()
+#     # 打印损失
+#     if (e + 1) % 1000 == 0:
+#         print('epoch: {}, loss: {}'.format(e+1, loss.item()))
+
+
+# def plot_seq(x):
+#     out = F.sigmoid(seq_net(Variable(torch.from_numpy(x).float()))).data.numpy()
+#     out = (out > 0.5) * 1
+#     return out
+
+# plot_decision_boundary(lambda x: plot_seq(x), x.numpy(), y.numpy())
+# plt.title('sequential')  
+# plt.savefig('fig-res-8.5.pdf')
+
+# torch.save(seq_net, 'save_seq_net.pth')      
+
+# # 读取保存的模型
+# seq_net1 = torch.load('save_seq_net.pth')
+# # 打印加载的模型
+# seq_net1
+
+# print(seq_net1[0].weight)
+
+# # 保存模型参数
+# torch.save(seq_net.state_dict(), 'save_seq_net_params.pth')    
+
+# # 定义网络架构
+# seq_net2 = nn.Sequential(
+#     nn.Linear(2, 4),
+#     nn.Tanh(),
+#     nn.Linear(4, 1)
+# )
+# # 加载网络参数
+# seq_net2.load_state_dict(torch.load('save_seq_net_params.pth'))
+
+# # 打印网络结构
+# seq_net2
+# print(seq_net2[0].weight)
+
+# class Module_Net(nn.Module):
+#     def __init__(self, num_input, num_hidden, num_output):
+#         super(Module_Net, self).__init__()
+#         self.layer1 = nn.Linear(num_input, num_hidden)
+#         self.layer2 = nn.Tanh()
+#         self.layer3 = nn.Linear(num_hidden, num_output)
+
+#     def forward(self, x):
+#         x = self.layer1(x)
+#         x = self.layer2(x)
+#         x = self.layer3(x)
+#         return x
+
+# mo_net = Module_Net(2, 4, 1)
+# # 访问模型中的某层可以直接通过名字， 网络第一层
+# l1 = mo_net.layer1
+# print(l1)
+
+
+# optim = torch.optim.SGD(mo_net.parameters(), 1.)
+#     # 训练 10000 次
+# for e in range(10000):
+#     # 网络正向计算
+#     out = mo_net(Variable(x))
+#     # 计算误差
+#     loss = criterion(out, Variable(y))
+#     # 误差反传、 更新参数
+#     optim.zero_grad()
+#     loss.backward()
+#     optim.step()
+#     # 打印损失
+#     if (e + 1) % 1000 == 0:
+#         print('epoch: {}, loss: {}'.format(e+1, loss.item()))
+
+# torch.save(mo_net.state_dict(), 'module_net.pth')
+
+
+
+
diff --git a/6_pytorch/fig-res-8.3.py b/6_pytorch/fig-res-8.3.py
new file mode 100644
index 0000000..ab996b2
--- /dev/null
+++ b/6_pytorch/fig-res-8.3.py
@@ -0,0 +1,86 @@
+import torch
+import numpy as np
+from torch import nn
+from torch.autograd import Variable
+import torch.nn.functional as F
+import matplotlib.pyplot as plt
+
+plt.rcParams['font.sans-serif']=['SimHei']
+plt.rcParams['axes.unicode_minus'] = False
+
+#%matplotlib inline
+np.random.seed(1)
+m = 400 # 样本数量
+N = int(m/2) # 每一类的点的个数
+D = 2 # 维度
+x = np.zeros((m, D))
+y = np.zeros((m, 1), dtype='uint8') # label 向量， 0 表示红色， 1 表示蓝色
+a = 4
+
+# 生成两类数据
+for j in range(2):
+    ix = range(N*j,N*(j+1))
+    t = np.linspace(j*3.12,(j+1)*3.12,N) + np.random.randn(N)*0.2 # theta
+    r = a*np.sin(4*t) + np.random.randn(N)*0.2 # radius
+    x[ix] = np.c_[r*np.sin(t), r*np.cos(t)]
+    y[ix] = j
+
+#尝试用逻辑回归解决
+x = torch.from_numpy(x).float()
+y = torch.from_numpy(y).float()
+
+w = nn.Parameter(torch.randn(2, 1))
+b = nn.Parameter(torch.zeros(1))
+
+# [w,b]是模型的参数； 1e-1是学习速率
+optimizer = torch.optim.SGD([w, b], 1e-1)
+criterion = nn.BCEWithLogitsLoss()
+def logistic_regression(x):
+    return torch.mm(x, w) + b
+
+
+for e in range(100):
+    # 模型正向计算
+    out = logistic_regression(Variable(x))
+    # 计算误差
+    loss = criterion(out, Variable(y))
+    # 误差反传和参数更新
+    optimizer.zero_grad()
+    loss.backward()
+    optimizer.step()
+    if (e + 1) % 20 == 0:
+        print('epoch:{}, loss:{}'.format(e+1, loss.item()))
+
+
+def plot_decision_boundary(model, x, y):
+    # Set min and max values and give it some padding
+    x_min, x_max = x[:, 0].min() - 1, x[:, 0].max() + 1
+    y_min, y_max = x[:, 1].min() - 1, x[:, 1].max() + 1 
+    h = 0.01
+    # Generate a grid of points with distance h between them
+    xx, yy = np.meshgrid(np.arange(x_min, x_max, h), np.arange(y_min,y_max, h))    
+
+    # Predict the function value for the whole grid .c_ 按行连接两个矩阵，左右相加。
+    Z = model(np.c_[xx.ravel(), yy.ravel()])
+    Z = Z.reshape(xx.shape)
+    # Plot the contour and training examples
+    plt.contourf(xx, yy, Z, cmap=plt.cm.Spectral)
+    plt.ylabel("x2")
+    plt.xlabel("x1")
+    for i in range(m):
+        if y[i] == 0:
+            plt.scatter(x[i, 0], x[i, 1], marker='8',c=0, s=40, cmap=plt.cm.Spectral)
+        else:
+            plt.scatter(x[i, 0], x[i, 1], marker='^',c=1, s=40)
+
+
+def plot_logistic(x):
+    x = Variable(torch.from_numpy(x).float())
+    out = F.sigmoid(logistic_regression(x))
+    out = (out > 0.5) * 1
+    return out.data.numpy()
+
+plot_decision_boundary(lambda x: plot_logistic(x), x.numpy(), y.numpy())
+plt.title('逻辑回归')
+plt.savefig('fig-res-8.3.pdf')
+plt.show()
\ No newline at end of file
diff --git a/6_pytorch/fig-res-8.4.py b/6_pytorch/fig-res-8.4.py
new file mode 100644
index 0000000..57caf94
--- /dev/null
+++ b/6_pytorch/fig-res-8.4.py
@@ -0,0 +1,91 @@
+import torch
+import numpy as np
+from torch import nn
+from torch.autograd import Variable
+import torch.nn.functional as F
+import matplotlib.pyplot as plt
+
+plt.rcParams['font.sans-serif']=['SimHei']
+plt.rcParams['axes.unicode_minus'] = False
+#%matplotlib inline
+np.random.seed(1)
+m = 400 # 样本数量
+N = int(m/2) # 每一类的点的个数
+D = 2 # 维度
+x = np.zeros((m, D))
+y = np.zeros((m, 1), dtype='uint8') # label 向量， 0 表示红色， 1 表示蓝色
+a = 4
+
+# 生成两类数据
+for j in range(2):
+    ix = range(N*j,N*(j+1))
+    t = np.linspace(j*3.12,(j+1)*3.12,N) + np.random.randn(N)*0.2 # theta
+    r = a*np.sin(4*t) + np.random.randn(N)*0.2 # radius
+    x[ix] = np.c_[r*np.sin(t), r*np.cos(t)]
+    y[ix] = j
+
+x = torch.from_numpy(x).float()
+y = torch.from_numpy(y).float()
+
+# 定义两层神经网络的参数
+w1 = nn.Parameter(torch.randn(2, 4) * 0.01) # 输入维度为2， 隐藏层神经元个数4
+b1 = nn.Parameter(torch.zeros(4))
+w2 = nn.Parameter(torch.randn(4, 1) * 0.01) # 隐层神经元为4， 输出单元为1
+b2 = nn.Parameter(torch.zeros(1))
+
+def mlp_network(x):
+    x1 = torch.mm(x, w1) + b1
+    x1 = F.tanh(x1) # 使用 PyTorch 自带的 tanh 激活函数
+    x2 = torch.mm(x1, w2) + b2
+    return x2
+
+# 定义优化器和损失函数
+optimizer = torch.optim.SGD([w1, w2, b1, b2], 1.)
+criterion = nn.BCEWithLogitsLoss()
+
+for e in range(10000):
+    # 正向计算
+    out = mlp_network(Variable(x))
+    # 计算误差
+    loss = criterion(out, Variable(y))
+    # 计算梯度并更新权重
+    optimizer.zero_grad()
+    loss.backward()
+    optimizer.step()
+    if (e + 1) % 1000 == 0:
+        print('epoch: {}, loss: {}'.format(e+1, loss.item()))
+
+def plot_decision_boundary(model, x, y):
+    # Set min and max values and give it some padding
+    x_min, x_max = x[:, 0].min() - 1, x[:, 0].max() + 1
+    y_min, y_max = x[:, 1].min() - 1, x[:, 1].max() + 1 
+    h = 0.01
+    # Generate a grid of points with distance h between them
+    xx, yy = np.meshgrid(np.arange(x_min, x_max, h), np.arange(y_min,y_max, h))    
+
+    # Predict the function value for the whole grid .c_ 按行连接两个矩阵，左右相加。
+    Z = model(np.c_[xx.ravel(), yy.ravel()])
+    Z = Z.reshape(xx.shape)
+    # Plot the contour and training examples
+    plt.contourf(xx, yy, Z, cmap=plt.cm.Spectral)
+    plt.ylabel("x2")
+    plt.xlabel("x1")
+    for i in range(m):
+        if y[i] == 0:
+            plt.scatter(x[i, 0], x[i, 1], marker='8',c=0, s=40, cmap=plt.cm.Spectral)
+        else:
+            plt.scatter(x[i, 0], x[i, 1], marker='^',c=1, s=40)
+
+def plot_network(x):
+    x = Variable(torch.from_numpy(x).float())
+    x1 = torch.mm(x, w1) + b1
+    x1 = F.tanh(x1)
+    x2 = torch.mm(x1, w2) + b2
+    out = F.sigmoid(x2)
+    out = (out > 0.5) * 1
+    return out.data.numpy()
+
+plot_decision_boundary(lambda x: plot_network(x), x.numpy(), y.numpy())
+plt.title('2层神经网络')
+plt.savefig('fig-res-8.4.pdf')    
+plt.show()
\ No newline at end of file
diff --git a/6_pytorch/fig-res-8.5.py b/6_pytorch/fig-res-8.5.py
new file mode 100644
index 0000000..673bc68
--- /dev/null
+++ b/6_pytorch/fig-res-8.5.py
@@ -0,0 +1,107 @@
+import torch
+import numpy as np
+from torch import nn
+from torch.autograd import Variable
+import torch.nn.functional as F
+import matplotlib.pyplot as plt
+import matplotlib as mpl
+
+plt.rcParams['font.sans-serif']=['SimHei']
+plt.rcParams['axes.unicode_minus'] = False
+
+#%matplotlib inline
+np.random.seed(1)
+m = 400 # 样本数量
+N = int(m/2) # 每一类的点的个数
+D = 2 # 维度
+x = np.zeros((m, D))
+y = np.zeros((m, 1), dtype='uint8') # label 向量， 0 表示红色， 1 表示蓝色
+a = 4
+
+criterion = nn.BCEWithLogitsLoss()
+
+# 生成两类数据
+for j in range(2):
+    ix = range(N*j,N*(j+1))
+    t = np.linspace(j*3.12,(j+1)*3.12,N) + np.random.randn(N)*0.2 # theta
+    r = a*np.sin(4*t) + np.random.randn(N)*0.2 # radius
+    x[ix] = np.c_[r*np.sin(t), r*np.cos(t)]
+    y[ix] = j
+
+
+def plot_decision_boundary(model, x, y):
+    # Set min and max values and give it some padding
+    x_min, x_max = x[:, 0].min() - 1, x[:, 0].max() + 1
+    y_min, y_max = x[:, 1].min() - 1, x[:, 1].max() + 1 
+    h = 0.01
+    # Generate a grid of points with distance h between them
+    xx, yy = np.meshgrid(np.arange(x_min, x_max, h), np.arange(y_min,y_max, h))    
+
+    # Predict the function value for the whole grid .c_ 按行连接两个矩阵，左右相加。
+    Z = model(np.c_[xx.ravel(), yy.ravel()])
+    Z = Z.reshape(xx.shape)
+    # Plot the contour and training examples
+    plt.contourf(xx, yy, Z, cmap=plt.cm.Spectral)
+    plt.ylabel("x2")
+    plt.xlabel("x1")
+    for i in range(m):
+        if y[i] == 0:
+            plt.scatter(x[i, 0], x[i, 1], marker='8',c=0, s=40, cmap=plt.cm.Spectral)
+        else:
+            plt.scatter(x[i, 0], x[i, 1], marker='^',c=1, s=40)
+
+#尝试用逻辑回归解决
+x = torch.from_numpy(x).float()
+y = torch.from_numpy(y).float()
+
+
+# Sequential
+seq_net = nn.Sequential(
+    nn.Linear(2, 4), # PyTorch 中的线性层， wx + b
+    nn.Tanh(),
+    nn.Linear(4, 1)
+)
+
+# 序列模块可以通过索引访问每一层
+seq_net[0] # 第一层
+
+# 打印出第一层的权重
+w0 = seq_net[0].weight
+print(w0)
+
+
+# 通过 parameters 可以取得模型的参数
+param = seq_net.parameters()
+# 定义优化器
+optim = torch.optim.SGD(param, 1.)
+
+# 训练 10000 次
+for e in range(10000):
+    # 网络正向计算
+    out = seq_net(Variable(x))
+    # 计算误差
+    loss = criterion(out, Variable(y))
+    # 反向传播、 更新权重
+    optim.zero_grad()
+    loss.backward()
+    optim.step()
+    # 打印损失
+    if (e + 1) % 1000 == 0:
+        print('epoch: {}, loss: {}'.format(e+1, loss.item()))
+
+
+def plot_seq(x):
+    out = F.sigmoid(seq_net(Variable(torch.from_numpy(x).float()))).data.numpy()
+    out = (out > 0.5) * 1
+    return out
+
+plot_decision_boundary(lambda x: plot_seq(x), x.numpy(), y.numpy())
+mpl.rcParams['font.family'] = 'SimHei' 
+plt.rcParams['axes.unicode_minus'] = False 
+
+# plt.title('序列化网络')  
+# plt.savefig('fig-res-8.5.pdf')
+plt.title('模块定义网络')  
+plt.savefig('fig-res-8.6.pdf')
+plt.show()
+torch.save(seq_net, 'save_seq_net.pth')
\ No newline at end of file
diff --git a/6_pytorch/fig-res-8.6.py b/6_pytorch/fig-res-8.6.py
new file mode 100644
index 0000000..2e05ed6
--- /dev/null
+++ b/6_pytorch/fig-res-8.6.py
@@ -0,0 +1,116 @@
+import torch
+import numpy as np
+from torch import nn
+from torch.autograd import Variable
+import torch.nn.functional as F
+import matplotlib.pyplot as plt
+
+#%matplotlib inline
+np.random.seed(1)
+m = 400 # 样本数量
+N = int(m/2) # 每一类的点的个数
+D = 2 # 维度
+x = np.zeros((m, D))
+y = np.zeros((m, 1), dtype='uint8') # label 向量， 0 表示红色， 1 表示蓝色
+a = 4
+
+criterion = nn.BCEWithLogitsLoss()
+
+# 生成两类数据
+for j in range(2):
+    ix = range(N*j,N*(j+1))
+    t = np.linspace(j*3.12,(j+1)*3.12,N) + np.random.randn(N)*0.2 # theta
+    r = a*np.sin(4*t) + np.random.randn(N)*0.2 # radius
+    x[ix] = np.c_[r*np.sin(t), r*np.cos(t)]
+    y[ix] = j
+
+
+def plot_decision_boundary(model, x, y):
+    # Set min and max values and give it some padding
+    x_min, x_max = x[:, 0].min() - 1, x[:, 0].max() + 1
+    y_min, y_max = x[:, 1].min() - 1, x[:, 1].max() + 1 
+    h = 0.01
+    # Generate a grid of points with distance h between them
+    xx, yy = np.meshgrid(np.arange(x_min, x_max, h), np.arange(y_min,y_max, h))    
+
+    # Predict the function value for the whole grid .c_ 按行连接两个矩阵，左右相加。
+    Z = model(np.c_[xx.ravel(), yy.ravel()])
+    Z = Z.reshape(xx.shape)
+    # Plot the contour and training examples
+    plt.contourf(xx, yy, Z, cmap=plt.cm.Spectral)
+    plt.ylabel("x2")
+    plt.xlabel("x1")
+    for i in range(m):
+        if y[i] == 0:
+            plt.scatter(x[i, 0], x[i, 1], marker='8',c=0, s=40, cmap=plt.cm.Spectral)
+        else:
+            plt.scatter(x[i, 0], x[i, 1], marker='^',c=1, s=40)
+
+#尝试用逻辑回归解决
+x = torch.from_numpy(x).float()
+y = torch.from_numpy(y).float()
+
+seq_net = nn.Sequential(
+    nn.Linear(2, 4), # PyTorch 中的线性层， wx + b
+    nn.Tanh(),
+    nn.Linear(4, 1)
+)
+
+# 读取保存的模型
+seq_net1 = torch.load('save_seq_net.pth')
+# 打印加载的模型
+seq_net1
+
+print(seq_net1[0].weight)
+
+# 保存模型参数
+torch.save(seq_net.state_dict(), 'save_seq_net_params.pth')    
+
+# 定义网络架构
+seq_net2 = nn.Sequential(
+    nn.Linear(2, 4),
+    nn.Tanh(),
+    nn.Linear(4, 1)
+)
+# 加载网络参数
+seq_net2.load_state_dict(torch.load('save_seq_net_params.pth'))
+
+# 打印网络结构
+seq_net2
+print(seq_net2[0].weight)
+
+class Module_Net(nn.Module):
+    def __init__(self, num_input, num_hidden, num_output):
+        super(Module_Net, self).__init__()
+        self.layer1 = nn.Linear(num_input, num_hidden)
+        self.layer2 = nn.Tanh()
+        self.layer3 = nn.Linear(num_hidden, num_output)
+
+    def forward(self, x):
+        x = self.layer1(x)
+        x = self.layer2(x)
+        x = self.layer3(x)
+        return x
+
+mo_net = Module_Net(2, 4, 1)
+# 访问模型中的某层可以直接通过名字， 网络第一层
+l1 = mo_net.layer1
+print(l1)
+
+
+optim = torch.optim.SGD(mo_net.parameters(), 1.)
+    # 训练 10000 次
+for e in range(10000):
+    # 网络正向计算
+    out = mo_net(Variable(x))
+    # 计算误差
+    loss = criterion(out, Variable(y))
+    # 误差反传、 更新参数
+    optim.zero_grad()
+    loss.backward()
+    optim.step()
+    # 打印损失
+    if (e + 1) % 1000 == 0:
+        print('epoch: {}, loss: {}'.format(e+1, loss.item()))
+
+torch.save(mo_net.state_dict(), 'module_net.pth')
\ No newline at end of file
-- 
Gitee