def avg_pool(self, bottom, name): return tf.nn.avg_pool(bottom, ksize=[1, 2, 2, 1], strides=[1, 2, 2, 1], padding='SAME', name=name) def max_pool(self, bottom, name): return tf.nn.max_pool(bottom, ksize=[1, 2, 2, 1], strides=[1, 2, 2, 1], padding='SAME', name=name) def conv_layer(self, bottom, name): with tf.variable_scope(name): filt = self.get_conv_filter(name) conv = tf.nn.conv2d(bottom, filt, [1, 1, 1, 1], padding='SAME') conv_biases = self.get_bias(name) bias = tf.nn.bias_add(conv, conv_biases) relu = tf.nn.relu(bias) return relu

这段代码定义了三个函数，用于构建VGG19模型中的卷积层和池化层。

avg_pool()函数用于定义平均池化层，其中bottom表示输入tensor，ksize表示池化窗口大小为[1, 2, 2, 1]，strides表示步长为[1, 2, 2, 1]，padding表示填充方式为'SAME'。

max_pool()函数用于定义最大池化层，其输入参数和参数设置与avg_pool()函数类似，只不过池化的方式不同。

conv_layer()函数用于定义卷积层，其中bottom表示输入tensor，name表示该卷积层的名称。在函数内部，首先调用了get_conv_filter()函数获取该卷积层的卷积核，然后使用tf.nn.conv2d()函数进行卷积操作，再调用get_bias()函数获取该卷积层的偏置，使用tf.nn.bias_add()函数加上偏置，最后使用ReLU激活函数激活输出结果，并将其返回。

相关问题

详细分析代码“def cnn_model(features, target): target = tf.one_hot(target, 15, 1, 0) #对词编码 word_vectors = tf.contrib.layers.embed_sequence(features ,vocab_size=n_words ,embed_dim=EMBEDDING_SIZE ,scope='words') word_vectors = tf.expand_dims(word_vectors, 3) with tf.variable_scope('CNN_Layer1'): # 添加卷积层做滤波 conv1 = tf.contrib.layers.convolution2d(word_vectors ,N_FILTERS #滤波数10 ,FILTER_SHAPE1 ,padding='VALID') # 添加RELU非线性 conv1 = tf.nn.relu(conv1) # 最大池化 pool1 = tf.nn.max_pool(conv1 ,ksize=[1, POOLING_WINDOW, 1, 1]#ksize池化窗口大小[1,4,1,1] ,strides=[1, POOLING_STRIDE, 1, 1]#步长[1,2,1,1] ,padding='SAME')#填充补0 # 对矩阵进行转置，以满足形状 pool1 = tf.transpose(pool1, [0, 1, 3, 2]) with tf.variable_scope('CNN_Layer2'):”每一句代码的详细作用，用了什么函数什么参数有什么作用，什么含义，并添加详细注释

代码分析如下：

def cnn_model(features, target):
    # 对target进行one-hot编码
    target = tf.one_hot(target, 15, 1, 0)
    # 对features中的词进行embedding，得到词向量
    word_vectors = tf.contrib.layers.embed_sequence(features,
                                                     vocab_size=n_words,
                                                     embed_dim=EMBEDDING_SIZE,
                                                     scope='words')
    # 在词向量上增加一个维度，用于卷积
    word_vectors = tf.expand_dims(word_vectors, 3)
    
    with tf.variable_scope('CNN_Layer1'):
        # 添加卷积层
        conv1 = tf.contrib.layers.convolution2d(word_vectors,
                                                N_FILTERS,
                                                FILTER_SHAPE1,
                                                padding='VALID')
        # 对卷积结果进行ReLU非线性变换
        conv1 = tf.nn.relu(conv1)
        # 对卷积结果进行最大池化
        pool1 = tf.nn.max_pool(conv1,
                               ksize=[1, POOLING_WINDOW, 1, 1],
                               strides=[1, POOLING_STRIDE, 1, 1],
                               padding='SAME')
        # 对池化结果进行转置，以满足形状要求
        pool1 = tf.transpose(pool1, [0, 1, 3, 2])
    
    with tf.variable_scope('CNN_Layer2'):
        # 添加卷积层
        conv2 = tf.contrib.layers.convolution2d(pool1,
                                                N_FILTERS,
                                                FILTER_SHAPE2,
                                                padding='VALID')
        # 对卷积结果进行ReLU非线性变换
        conv2 = tf.nn.relu(conv2)
        # 对卷积结果进行最大池化
        pool2 = tf.squeeze(tf.reduce_max(conv2, 1), squeeze_dims=[1])
    
    # 将池化结果送入全连接层，输出最终的分类结果
    logits = tf.contrib.layers.fully_connected(pool2, 15, activation_fn=None)
    loss = tf.losses.softmax_cross_entropy(target, logits)
    train_op = tf.contrib.layers.optimize_loss(loss, tf.contrib.framework.get_global_step(),
                                               optimizer='Adam', learning_rate=LEARNING_RATE)
    
    return ({
        'class': tf.argmax(logits, 1),
        'prob': tf.nn.softmax(logits)
    }, loss, train_op)

1. `tf.one_hot(target, 15, 1, 0)`：对target进行one-hot编码，将每个词转化为一个长度为15的向量，其中对应的位置为1，其余为0。
2. `tf.contrib.layers.embed_sequence(features, vocab_size=n_words, embed_dim=EMBEDDING_SIZE, scope='words')`：对features（即输入的词）进行embedding，将每个词转化为一个EMBEDDING_SIZE维的向量。
3. `tf.expand_dims(word_vectors, 3)`：在词向量上增加一个维度，用于卷积。
4. `tf.contrib.layers.convolution2d(word_vectors, N_FILTERS, FILTER_SHAPE1, padding='VALID')`：添加卷积层，使用N_FILTERS个大小为FILTER_SHAPE1的滤波器进行卷积操作。
5. `tf.nn.relu(conv1)`：对卷积结果进行ReLU非线性变换。
6. `tf.nn.max_pool(conv1, ksize=[1, POOLING_WINDOW, 1, 1], strides=[1, POOLING_STRIDE, 1, 1], padding='SAME')`：对卷积结果进行最大池化，使用大小为POOLING_WINDOW的池化窗口，步长为POOLING_STRIDE。
7. `tf.transpose(pool1, [0, 1, 3, 2])`：对池化结果进行转置，将第3维和第4维交换，以满足后续卷积层的输入要求。
8. `tf.contrib.layers.convolution2d(pool1, N_FILTERS, FILTER_SHAPE2, padding='VALID')`：添加卷积层，使用N_FILTERS个大小为FILTER_SHAPE2的滤波器进行卷积操作。
9. `tf.nn.relu(conv2)`：对卷积结果进行ReLU非线性变换。
10. `tf.squeeze(tf.reduce_max(conv2, 1), squeeze_dims=[1])`：对卷积结果进行最大池化，并去除不必要的维度。
11. `tf.contrib.layers.fully_connected(pool2, 15, activation_fn=None)`：将池化结果送入全连接层，输出最终的分类结果。
12. `tf.losses.softmax_cross_entropy(target, logits)`：计算损失函数，使用softmax交叉熵作为损失函数。
13. `tf.contrib.layers.optimize_loss(loss, tf.contrib.framework.get_global_step(), optimizer='Adam', learning_rate=LEARNING_RATE)`：使用Adam优化器最小化损失函数，更新模型参数。

# GRADED FUNCTION: forward_propagation def forward_propagation(X, parameters): """ Implements the forward propagation for the model: CONV2D -> RELU -> MAXPOOL -> CONV2D -> RELU -> MAXPOOL -> FLATTEN -> FULLYCONNECTED Arguments: X -- input dataset placeholder, of shape (input size, number of examples) parameters -- python dictionary containing your parameters "W1", "W2" the shapes are given in initialize_parameters Returns: Z3 -- the output of the last LINEAR unit """ # Retrieve the parameters from the dictionary "parameters" W1 = parameters['W1'] W2 = parameters['W2'] ### START CODE HERE ### # CONV2D: stride of 1, padding 'SAME' Z1 = tf.nn.conv2d(X, W1, strides=[1, 1, 1, 1], padding='SAME') # RELU A1 = tf.nn.relu(Z1) # MAXPOOL: window 8x8, sride 8, padding 'SAME' P1 = tf.nn.max_pool(A1, ksize=[1, 8, 8, 1], strides=[1, 8, 8, 1], padding='SAME') # CONV2D: filters W2, stride 1, padding 'SAME' Z2 = tf.nn.conv2d(P1, W2, strides=[1, 1, 1, 1], padding='SAME') # RELU A2 = tf.nn.relu(Z2) # MAXPOOL: window 4x4, stride 4, padding 'SAME' P2 = tf.nn.max_pool(A2, ksize=[1, 4, 4, 1], strides=[1, 4, 4, 1], padding='SAME') # FLATTEN P2 = tf.contrib.layers.flatten(P2) # FULLY-CONNECTED without non-linear activation function (not not call softmax). # 6 neurons in output layer. Hint: one of the arguments should be "activation_fn=None" Z3 = tf.contrib.layers.fully_connected(P2, 6, activation_fn=None) ### END CODE HERE ### return Z3 tf.reset_default_graph() with tf.Session() as sess: np.random.seed(1) X, Y = create_placeholders(64, 64, 3, 6) parameters = initialize_parameters() Z3 = forward_propagation(X, parameters) init = tf.global_variables_initializer() sess.run(init) a = sess.run(Z3, {X: np.random.randn(2,64,64,3), Y: np.random.randn(2,6)}) print("Z3 = " + str(a)) 请根据现在python版本修改这段代码

这段代码是基于TensorFlow 1.x版本的，如果你使用的是TensorFlow 2.x版本，需要对代码进行一些修改。下面是修改后的代码：

import tensorflow as tf

def forward_propagation(X, parameters):
    """
    Implements the forward propagation for the model:
    CONV2D -> RELU -> MAXPOOL -> CONV2D -> RELU -> MAXPOOL -> FLATTEN -> FULLYCONNECTED

    Arguments:
    X -- input dataset placeholder, of shape (input size, number of examples)
    parameters -- python dictionary containing your parameters "W1", "W2"
                  the shapes are given in initialize_parameters

    Returns:
    Z3 -- the output of the last LINEAR unit
    """

    # Retrieve the parameters from the dictionary "parameters"
    W1 = parameters['W1']
    W2 = parameters['W2']

    # CONV2D: stride of 1, padding 'SAME'
    Z1 = tf.nn.conv2d(X, W1, strides=[1, 1, 1, 1], padding='SAME')
    # RELU
    A1 = tf.nn.relu(Z1)
    # MAXPOOL: window 8x8, sride 8, padding 'SAME'
    P1 = tf.nn.max_pool2d(A1, ksize=[1, 8, 8, 1], strides=[1, 8, 8, 1], padding='SAME')
    # CONV2D: filters W2, stride 1, padding 'SAME'
    Z2 = tf.nn.conv2d(P1, W2, strides=[1, 1, 1, 1], padding='SAME')
    # RELU
    A2 = tf.nn.relu(Z2)
    # MAXPOOL: window 4x4, stride 4, padding 'SAME'
    P2 = tf.nn.max_pool2d(A2, ksize=[1, 4, 4, 1], strides=[1, 4, 4, 1], padding='SAME')
    # FLATTEN
    P2 = tf.reshape(P2, [-1, P2.shape[1] * P2.shape[2] * P2.shape[3]])
    # FULLY-CONNECTED without non-linear activation function (not not call softmax).
    # 6 neurons in output layer. Hint: one of the arguments should be "activation_fn=None"
    Z3 = tf.contrib.layers.fully_connected(P2, 6, activation_fn=None)

    return Z3

tf.random.set_seed(1)

with tf.compat.v1.Session() as sess:
    tf.compat.v1.reset_default_graph()
    X, Y = create_placeholders(64, 64, 3, 6)
    parameters = initialize_parameters()
    Z3 = forward_propagation(X, parameters)
    init = tf.compat.v1.global_variables_initializer()
    sess.run(init)
    a = sess.run(Z3, {X: np.random.randn(2,64,64,3), Y: np.random.randn(2,6)})
    print("Z3 = " + str(a))

这段代码已经修改为兼容TensorFlow 2.x版本，并进行了相应的调整。请注意，TensorFlow 2.x版本中的一些函数名称和用法可能与1.x版本有所不同。