[英]Input to tf.keras Conv2D layer not of appropriate size
我正在按照此处教程中概述的步骤进行操作
我正在尝试在Google Colaboratory笔记本内的单元格中从教程中运行以下代码:
import tensorflow as tf
mnist = tf.keras.datasets.mnist
(x_train, y_train), (x_test, y_test) =
tf.keras.datasets.fashion_mnist.load_data()
x_train = x_train.astype('float32') / 255
x_test = x_test.astype('float32') / 255
model = tf.keras.Sequential()
# Must define the input shape in the first layer of the neural network
model.add(tf.keras.layers.Conv2D(filters=64, kernel_size=2, padding='same', activation='relu', input_shape=(28,28,1)))
model.add(tf.keras.layers.MaxPooling2D(pool_size=2))
model.add(tf.keras.layers.Dropout(0.3))
model.add(tf.keras.layers.Conv2D(filters=32, kernel_size=2, padding='same', activation='relu'))
model.add(tf.keras.layers.MaxPooling2D(pool_size=2))
model.add(tf.keras.layers.Dropout(0.3))
model.add(tf.keras.layers.Flatten())
model.add(tf.keras.layers.Dense(256, activation='relu'))
model.add(tf.keras.layers.Dropout(0.5))
model.add(tf.keras.layers.Dense(10, activation='softmax'))
# Take a look at the model summary
model.compile(loss='categorical_crossentropy',
optimizer='adam',
metrics=['accuracy'])
model.fit(x_train,
y_train,
batch_size=64,
epochs=10)
# Evaluate the model on test set
score = model.evaluate(x_test, y_test, verbose=0)
# Print test accuracy
print('\n', 'Test accuracy:', score[1])
运行单元格时,出现以下错误:
Error when checking input: expected conv2d_5_input to have 4 dimensions, but got array with shape (60000, 28, 28)
我觉得我缺少了使用卷积层的基础知识,尽管看起来这本应该起作用。 我在SO上发现了一些类似的问题,人们建议操纵“ input_shape”参数。 我尝试将其更改为(60000,28,28),并且还添加了附加尺寸,其值为1,但到目前为止没有任何效果。 谁能指出我可能在这里缺少什么?
您似乎跳过了本教程的重塑部分:
# Reshape input data from (28, 28) to (28, 28, 1)
w, h = 28, 28
x_train = x_train.reshape(x_train.shape[0], w, h, 1)
x_valid = x_valid.reshape(x_valid.shape[0], w, h, 1)
x_test = x_test.reshape(x_test.shape[0], w, h, 1)
这里的想法是您的样本为28x28x1(一种颜色,28x28像素),并且第一个维度是样本的数量(在您的情况下为60000)。
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