人工智能作业2

# -*- coding: utf-8 -*-
"""
Neural Networks
===============

Neural networks can be constructed using the ``torch.nn`` package.

Now that you had a glimpse of ``autograd``, ``nn`` depends on
``autograd`` to define models and differentiate them.
An ``nn.Module`` contains layers, and a method ``forward(input)``\ that
returns the ``output``.

For example, look at this network that classifies digit images:

.. figure:: /_static/img/mnist.png
   :alt: convnet

   convnet

It is a simple feed-forward network. It takes the input, feeds it
through several layers one after the other, and then finally gives the
output.

A typical training procedure for a neural network is as follows:

- Define the neural network that has some learnable parameters (or
  weights)
- Iterate over a dataset of inputs
- Process input through the network
- Compute the loss (how far is the output from being correct)
- Propagate gradients back into the network’s parameters
- Update the weights of the network, typically using a simple update rule:
  ``weight = weight - learning_rate * gradient``

Define the network
------------------

Let’s define this network:
"""
import torch
import torch.nn as nn
import torch.nn.functional as F


class Net(nn.Module):

    def __init__(self):
        super(Net, self).__init__()
        # 1 input image channel, 6 output channels, 5x5 square convolution
        # kernel
        self.conv1 = nn.Conv2d(1, 6, 5)
        self.conv2 = nn.Conv2d(6, 16, 5)
        # an affine operation: y = Wx + b
        self.fc1 = nn.Linear(16 * 5 * 5, 120)
        self.fc2 = nn.Linear(120, 84)
        self.fc3 = nn.Linear(84, 10)

    def forward(self, x):
        # Max pooling over a (2, 2) window
        x = F.max_pool2d(F.relu(self.conv1(x)), (2, 2))
        # If the size is a square you can only specify a single number
        x = F.max_pool2d(F.relu(self.conv2(x)), 2)
        x = x.view(-1, self.num_flat_features(x))
        x = F.relu(self.fc1(x))
        x = F.relu(self.fc2(x))
        x = self.fc3(x)
        return x

    def num_flat_features(self, x):
        size = x.size()[1:]  # all dimensions except the batch dimension
        num_features = 1
        for s in size:
            num_features *= s
        return num_features


net = Net()
print(net)

########################################################################
# You just have to define the ``forward`` function, and the ``backward``
# function (where gradients are computed) is automatically defined for you
# using ``autograd``.
# You can use any of the Tensor operations in the ``forward`` function.
#
# The learnable parameters of a model are returned by ``net.parameters()``

params = list(net.parameters())
print(len(params))
print(params[0].size())  # conv1's .weight

########################################################################
# Let try a random 32x32 input
# Note: Expected input size to this net(LeNet) is 32x32. To use this net on
# MNIST dataset, please resize the images from the dataset to 32x32.

input = torch.randn(1, 1, 32, 32)
out = net(input)
print(out)

########################################################################
# Zero the gradient buffers of all parameters and backprops with random
# gradients:
net.zero_grad()
out.backward(torch.randn(1, 10))

########################################################################
# .. note::
#
#     ``torch.nn`` only supports mini-batches. The entire ``torch.nn``
#     package only supports inputs that are a mini-batch of samples, and not
#     a single sample.
#
#     For example, ``nn.Conv2d`` will take in a 4D Tensor of
#     ``nSamples x nChannels x Height x Width``.
#
#     If you have a single sample, just use ``input.unsqueeze(0)`` to add
#     a fake batch dimension.
#
# Before proceeding further, let's recap all the classes you’ve seen so far.
#
# **Recap:**
#   -  ``torch.Tensor`` - A *multi-dimensional array* with support for autograd
#      operations like ``backward()``. Also *holds the gradient* w.r.t. the
#      tensor.
#   -  ``nn.Module`` - Neural network module. *Convenient way of
#      encapsulating parameters*, with helpers for moving them to GPU,
#      exporting, loading, etc.
#   -  ``nn.Parameter`` - A kind of Tensor, that is *automatically
#      registered as a parameter when assigned as an attribute to a*
#      ``Module``.
#   -  ``autograd.Function`` - Implements *forward and backward definitions
#      of an autograd operation*. Every ``Tensor`` operation, creates at
#      least a single ``Function`` node, that connects to functions that
#      created a ``Tensor`` and *encodes its history*.
#
# **At this point, we covered:**
#   -  Defining a neural network
#   -  Processing inputs and calling backward
#
# **Still Left:**
#   -  Computing the loss
#   -  Updating the weights of the network
#
# Loss Function
# -------------
# A loss function takes the (output, target) pair of inputs, and computes a
# value that estimates how far away the output is from the target.
#
# There are several different
# `loss functions <https://pytorch.org/docs/nn.html#loss-functions>`_ under the
# nn package .
# A simple loss is: ``nn.MSELoss`` which computes the mean-squared error
# between the input and the target.
#
# For example:

output = net(input)
target = torch.randn(10)  # a dummy target, for example
target = target.view(1, -1)  # make it the same shape as output
criterion = nn.MSELoss()

loss = criterion(output, target)
print(loss)

########################################################################
# Now, if you follow ``loss`` in the backward direction, using its
# ``.grad_fn`` attribute, you will see a graph of computations that looks
# like this:
#
# ::
#
#     input -> conv2d -> relu -> maxpool2d -> conv2d -> relu -> maxpool2d
#           -> view -> linear -> relu -> linear -> relu -> linear
#           -> MSELoss
#           -> loss
#
# So, when we call ``loss.backward()``, the whole graph is differentiated
# w.r.t. the loss, and all Tensors in the graph that has ``requires_grad=True``
# will have their ``.grad`` Tensor accumulated with the gradient.
#
# For illustration, let us follow a few steps backward:

print(loss.grad_fn)  # MSELoss
print(loss.grad_fn.next_functions[0][0])  # Linear
print(loss.grad_fn.next_functions[0][0].next_functions[0][0])  # ReLU

########################################################################
# Backprop
# --------
# To backpropagate the error all we have to do is to ``loss.backward()``.
# You need to clear the existing gradients though, else gradients will be
# accumulated to existing gradients.
#
#
# Now we shall call ``loss.backward()``, and have a look at conv1's bias
# gradients before and after the backward.


net.zero_grad()     # zeroes the gradient buffers of all parameters

print('conv1.bias.grad before backward')
print(net.conv1.bias.grad)

loss.backward()

print('conv1.bias.grad after backward')
print(net.conv1.bias.grad)

########################################################################
# Now, we have seen how to use loss functions.
#
# **Read Later:**
#
#   The neural network package contains various modules and loss functions
#   that form the building blocks of deep neural networks. A full list with
#   documentation is `here <https://pytorch.org/docs/nn>`_.
#
# **The only thing left to learn is:**
#
#   - Updating the weights of the network
#
# Update the weights
# ------------------
# The simplest update rule used in practice is the Stochastic Gradient
# Descent (SGD):
#
#      ``weight = weight - learning_rate * gradient``
#
# We can implement this using simple python code:
#
# .. code:: python
#
#     learning_rate = 0.01
#     for f in net.parameters():
#         f.data.sub_(f.grad.data * learning_rate)
#
# However, as you use neural networks, you want to use various different
# update rules such as SGD, Nesterov-SGD, Adam, RMSProp, etc.
# To enable this, we built a small package: ``torch.optim`` that
# implements all these methods. Using it is very simple:

import torch.optim as optim

# create your optimizer
optimizer = optim.SGD(net.parameters(), lr=0.01)

# in your training loop:
optimizer.zero_grad()   # zero the gradient buffers
output = net(input)
loss = criterion(output, target)
loss.backward()
optimizer.step()    # Does the update


###############################################################
# .. Note::
#
#       Observe how gradient buffers had to be manually set to zero using
#       ``optimizer.zero_grad()``. This is because gradients are accumulated
#       as explained in `Backprop`_ section.

 

 vgg代码

# 从keras.model中导入model模块，为函数api搭建网络做准备
from keras.models import Model
from keras.layers import Flatten, Dense, Dropout, MaxPooling2D, Conv2D, BatchNormalization, Input, ZeroPadding2D, \
    Concatenate
from keras.layers.convolutional import AveragePooling2D
from keras import regularizers  # 正则化
from tensorflow.python.keras.optimizers import adam_v2
from tensorflow.python.keras.optimizers import rmsprop_v2 # 优化选择器
from keras.layers import AveragePooling2D
from keras.datasets import mnist
from keras.utils import np_utils
import matplotlib.pyplot as plt
import numpy as np

# 数据处理
(X_train, Y_train), (X_test, Y_test) = mnist.load_data()
X_test1 = X_test
Y_test1 = Y_test
X_train = X_train.reshape(-1, 28, 28, 1).astype("float32") / 255.0
X_test = X_test.reshape(-1, 28, 28, 1).astype("float32") / 255.0
Y_train = np_utils.to_categorical(Y_train, 10)
Y_test = np_utils.to_categorical(Y_test, 10)
print(X_train.shape)
print(Y_train.shape)
print(X_train.shape)


def vgg16():
    x_input = Input((28, 28, 1))  # 输入数据形状28*28*1
    # Block 1
    x = Conv2D(64, (3, 3), activation='relu', padding='same', name='block1_conv1')(x_input)
    x = Conv2D(64, (3, 3), activation='relu', padding='same', name='block1_conv2')(x)
    x = MaxPooling2D((2, 2), strides=(2, 2), name='block1_pool')(x)

    # Block 2
    x = Conv2D(128, (3, 3), activation='relu', padding='same', name='block2_conv1')(x)
    x = Conv2D(128, (3, 3), activation='relu', padding='same', name='block2_conv2')(x)
    x = MaxPooling2D((2, 2), strides=(2, 2), name='block2_pool')(x)

    # Block 3
    x = Conv2D(256, (3, 3), activation='relu', padding='same', name='block3_conv1')(x)
    x = Conv2D(256, (3, 3), activation='relu', padding='same', name='block3_conv2')(x)
    x = Conv2D(256, (3, 3), activation='relu', padding='same', name='block3_conv3')(x)
    x = MaxPooling2D((2, 2), strides=(2, 2), name='block3_pool')(x)

    # Block 4
    x = Conv2D(512, (3, 3), activation='relu', padding='same', name='block4_conv1')(x)
    x = Conv2D(512, (3, 3), activation='relu', padding='same', name='block4_conv2')(x)
    x = Conv2D(512, (3, 3), activation='relu', padding='same', name='block4_conv3')(x)
    x = MaxPooling2D((2, 2), strides=(2, 2), name='block4_pool')(x)

    # Block 5
    x = Conv2D(512, (3, 3), activation='relu', padding='same', name='block5_conv1')(x)
    x = Conv2D(512, (3, 3), activation='relu', padding='same', name='block5_conv2')(x)
    x = Conv2D(512, (3, 3), activation='relu', padding='same', name='block5_conv3')(x)

    # BLOCK 6
    x = Flatten()(x)
    x = Dense(256, activation="relu")(x)
    x = Dropout(0.5)(x)
    x = Dense(256, activation="relu")(x)
    x = Dropout(0.5)(x)
    # 搭建最后一层，即输出层
    x = Dense(10, activation="softmax")(x)
    # 调用MDOEL函数，定义该网络模型的输入层为X_input,输出层为x.即全连接层
    model = Model(inputs=x_input, outputs=x)
    # 查看网络模型的摘要
    model.summary()
    return model


model = vgg16()
optimizer = RMSprop(lr=1e-4)
model.compile(loss="binary_crossentropy", optimizer=optimizer, metrics=["accuracy"])
# 训练加评估模型
n_epoch = 4
batch_size = 128


def run_model():  # 训练模型
    training = model.fit(
        X_train,
        Y_train,
        batch_size=batch_size,
        epochs=n_epoch,
        validation_split=0.25,
        verbose=1
    )
    test = model.evaluate(X_train, Y_train, verbose=1)
    return training, test


training, test = run_model()
print("误差：", test[0])
print("准确率：", test[1])


def show_train(training_history, train, validation):
    plt.plot(training.history[train], linestyle="-", color="b")
    plt.plot(training.history[validation], linestyle="--", color="r")
    plt.title("training history")
    plt.xlabel("epoch")
    plt.ylabel("accuracy")
    plt.legend(["training", "validation"], loc="lower right")
    plt.show()


show_train(training, "accuracy", "val_accuracy")


def show_train1(training_history, train, validation):
    plt.plot(training.history[train], linestyle="-", color="b")
    plt.plot(training.history[validation], linestyle="--", color="r")
    plt.title("training history")
    plt.xlabel("epoch")
    plt.ylabel("loss")
    plt.legend(["training", "validation"], loc="upper right")
    plt.show()


show_train1(training, "loss", "val_loss")

prediction = model.predict(X_test)


def image_show(image):
    fig = plt.gcf()  # 获取当前图像
    fig.set_size_inches(2, 2)  # 改变图像大小
    plt.imshow(image, cmap="binary")  # 显示图像
    plt.show()


def result(i):
    image_show(X_test1[i])
    print("真实值：", Y_test1[i])
    print("预测值：", np.argmax(prediction[i]))


result(0)
result(1)

 

 

 

 

 

 vgg课本上的代码

import tensorflow as tf
from tensorflow import keras
from tensorflow.keras import layers, regularizers
import numpy as np
import os
import cv2
import matplotlib.pyplot as plt


os.environ["CUDA_VISIBLE_DEVICES"] = "1"
resize = 224
path =r"C:\train"

def load_data():
    imgs = os.listdir(path)
    num = len(imgs)
    train_data = np.empty((5000, resize, resize, 3), dtype="int32")
    train_label = np.empty((5000, ), dtype="int32")
    test_data = np.empty((5000, resize, resize, 3), dtype="int32")
    test_label = np.empty((5000, ), dtype="int32")
    for i in range(5000):
        if i % 2:
            train_data[i] = cv2.resize(cv2.imread(path+'/'+ 'dog.' + str(i) + '.jpg'), (resize, resize))
            train_label[i] = 1
        else:
            train_data[i] = cv2.resize(cv2.imread(path+'/' + 'cat.' + str(i) + '.jpg'), (resize, resize))
            train_label[i] = 0
    for i in range(5000, 10000):
        if i % 2:
            test_data[i-5000] = cv2.resize(cv2.imread(path+'/' + 'dog.' + str(i) + '.jpg'), (resize, resize))
            test_label[i-5000] = 1
        else:
            test_data[i-5000] = cv2.resize(cv2.imread(path+'/' + 'cat.' + str(i) + '.jpg'), (resize, resize))
            test_label[i-5000] = 0
    return train_data, train_label, test_data, test_label


def vgg16():
    weight_decay = 0.0005
    nb_epoch = 100
    batch_size = 32

    # layer1
    model = keras.Sequential()
    model.add(layers.Conv2D(64, (3, 3), padding='same',
                            input_shape=(224, 224, 3), kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    model.add(layers.Dropout(0.3))
    # layer2
    model.add(layers.Conv2D(64, (3, 3), padding='same', kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    model.add(layers.MaxPooling2D(pool_size=(2, 2)))
    # layer3
    model.add(layers.Conv2D(128, (3, 3), padding='same', kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    model.add(layers.Dropout(0.4))
    # layer4
    model.add(layers.Conv2D(128, (3, 3), padding='same', kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    model.add(layers.MaxPooling2D(pool_size=(2, 2)))
    # layer5
    model.add(layers.Conv2D(256, (3, 3), padding='same', kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    model.add(layers.Dropout(0.4))
    # layer6
    model.add(layers.Conv2D(256, (3, 3), padding='same', kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    model.add(layers.Dropout(0.4))
    # layer7
    model.add(layers.Conv2D(256, (3, 3), padding='same', kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    model.add(layers.MaxPooling2D(pool_size=(2, 2)))
    # layer8
    model.add(layers.Conv2D(512, (3, 3), padding='same', kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    model.add(layers.Dropout(0.4))
    # layer9
    model.add(layers.Conv2D(512, (3, 3), padding='same', kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    model.add(layers.Dropout(0.4))
    # layer10
    model.add(layers.Conv2D(512, (3, 3), padding='same', kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    model.add(layers.MaxPooling2D(pool_size=(2, 2)))
    # layer11
    model.add(layers.Conv2D(512, (3, 3), padding='same', kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    model.add(layers.Dropout(0.4))
    # layer12
    model.add(layers.Conv2D(512, (3, 3), padding='same', kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    model.add(layers.Dropout(0.4))
    # layer13
    model.add(layers.Conv2D(512, (3, 3), padding='same', kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    model.add(layers.MaxPooling2D(pool_size=(2, 2)))
    model.add(layers.Dropout(0.5))
    # layer14
    model.add(layers.Flatten())
    model.add(layers.Dense(512, kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    # layer15
    model.add(layers.Dense(512, kernel_regularizer=regularizers.l2(weight_decay)))
    model.add(layers.Activation('relu'))
    model.add(layers.BatchNormalization())
    # layer16
    model.add(layers.Dropout(0.5))
    model.add(layers.Dense(2))
    model.add(layers.Activation('softmax'))

    return model
#if __name__ == '__main__':
train_data, train_label, test_data, test_label = load_data()
train_data = train_data.astype('float32')
test_data = test_data.astype('float32')
train_label = keras.utils.to_categorical(train_label, 2)
test_label = keras.utils.to_categorical(test_label, 2)
#定义训练方法,超参数设置
model = vgg16()
sgd = tf.keras.optimizers.SGD(lr=0.01, decay=1e-6, momentum=0.9, nesterov=True) #设置优化器为SGD
model.compile(loss='categorical_crossentropy', optimizer=sgd, metrics=['accuracy'])
history = model.fit(train_data, train_label,
              batch_size=20,
              epochs=10,
              validation_split=0.2,  #把训练集中的五分之一作为验证集
              shuffle=True)
scores = model.evaluate(test_data,test_label,verbose=1)
print(scores)
model.save('model/vgg16dogcat.h5')
acc = history.history['accuracy']  # 获取训练集准确性数据
val_acc = history.history['val_accuracy']  # 获取验证集准确性数据
loss = history.history['loss']  # 获取训练集错误值数据
val_loss = history.history['val_loss']  # 获取验证集错误值数据
epochs = range(1, len(acc) + 1)
plt.plot(epochs, acc, 'bo', label='Trainning acc')  # 以epochs为横坐标，以训练集准确性为纵坐标
plt.plot(epochs, val_acc, 'b', label='Vaildation acc')  # 以epochs为横坐标，以验证集准确性为纵坐标
plt.legend()  # 绘制图例，即标明图中的线段代表何种含义
plt.show()