神经网络——项目二CNN手写数字识别

 1  2 import numpy as np
 3 from keras.models import Sequential
 4 from keras.layers.core import Dense, Dropout, Activation
 5 from keras.layers import Convolution2D, MaxPooling2D, Flatten
 6 from keras.optimizers import SGD, Adam
 7 from keras.utils import np_utils
 8 from keras.datasets import mnist
 9 #categrorical_crossentropy
10 
11 def load_data():
12     (x_train, y_train), (x_test, y_test) = mnist.load_data()
13     
14     #x_train = x_train[0:number]
15     #y_train = y_train[0:number]
16     x_train = x_train.reshape(x_train.shape[0], 1, 28, 28)
17     x_test = x_test.reshape(x_test.shape[0], 1, 28, 28)
18     x_train = x_train.astype('float32')
19     x_test = x_test.astype('float32')
20     # convert class vector to binary class matrices
21     y_train = np_utils.to_categorical(y_train, 10)
22     y_test = np_utils.to_categorical(y_test, 10)
23     x_train = x_train
24     x_test = x_test
25     #x_test = np.random.normal(x_test)
26     x_train = x_train / 255
27     x_test = x_test / 255
28     return (x_train, y_train), (x_test,y_test)
29 
30 (x_train, y_train), (x_test,y_test) = load_data()
31 
32 
33 model2 = Sequential()
34 model2.add(Convolution2D(25, 3, strides=3, input_shape=(1, 28, 28), data_format='channels_first', padding='same'))  
35 model2.add(MaxPooling2D((2, 2))) 
36 
37 
38 
39 
40 
41 model2.add(Convolution2D(50, 3, strides=3, padding='same')) 
42 model2.add(MaxPooling2D(2, 2))   
43 
44 
45 model2.add(Flatten())
46 
47 model2.add(Dense(128, activation='relu'))
48 model2.add(Dense(10, activation='softmax'))
49 
50 model2.compile(loss='mse', optimizer=SGD(lr=0.1), metrics=['accuracy'])
51 model2.fit(x_train, y_train, batch_size=200, epochs=10, verbose=1)
52 
53 result = model2.evaluate(x_test, y_test, verbose=0)
54 
55 print('
Test Acc:', result)

以上demo是可以运行,但需修改parameters 

过程所遇到的Error总结:

1.Negative dimension size caused by subtracting 3 from 1 for 'conv2d_1/convolution' (op: 'Conv2D') .....

2.ValueError: Negative dimension size caused by subtracting 2 from 1 for 'max_pooling2d_2/MaxPool' (op: 'MaxPool') with input shapes: [?,4,1,50].

解决方案如下:

 

 

原文地址:https://www.cnblogs.com/cfancy/p/12331853.html