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VincentWei

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简单CNN速写

VincentWei    2019-01-06 18:11

为什么要训练速度,如果你对一个事物,掌握的程度越高,你的速度就越快,训练速度,就是不断的加深理解!

以下代码,大概花了10+分钟,比比谁快!!!

写神经网络,无非就是写wx+b,注意SIZE要对!!!
    
    

# -*- coding: utf-8 -*-
"""
Created on Sat Jan  5 18:34:05 2019

@author: VincentWei
"""

import tensorflow as tf
from tensorflow.examples.tutorials.mnist import input_data

def weight_variable(shape):
    initial = tf.truncated_normal(shape, stddev=0.1)
    return tf.Variable(initial)


def bias_variable(shape):
    initial = tf.constant(1.0, shape=shape)
    return tf.Variable(initial)

def conv2d(x, W):
    return tf.nn.conv2d(x, W, [1, 1, 1, 1], padding='SAME')

def max_pool_2x2(x):
    return tf.nn.max_pool(x, ksize=[1, 2, 2, 1], 
                          strides=[1, 2, 2, 1], padding='SAME',)
    
    
if __name__ == '__main__':
    mnist = input_data.read_data_sets("MNIST_data/", one_hot=True)
    x = tf.placeholder(tf.float32, [None, 784])
    y_ = tf.placeholder(tf.float32, [None, 10])
    
    x_image = tf.reshape(x, [-1, 28, 28, 1])
    
    w_conv1 = weight_variable([5, 5, 1, 32])
    b_conv1 = bias_variable([32])
    h_conv1 = tf.nn.relu(conv2d(x_image, w_conv1) + b_conv1)
    h_pool1 = max_pool_2x2(h_conv1)
    
    w_conv2 = weight_variable([5, 5, 32, 64])
    b_conv2 = bias_variable([64])
    h_conv2 = tf.nn.relu(conv2d(h_pool1, w_conv2) + b_conv2)
    h_pool2 = max_pool_2x2(h_conv2)
    
    w_fc1 = weight_variable([7* 7 *64, 1024])
    b_fc1 = bias_variable([1024])
    h_pool2_flat = tf.reshape(h_pool2, [-1, 7 * 7 * 64])    
    h_fc1 = tf.nn.relu(tf.matmul(h_pool2_flat, w_fc1) + b_fc1)
    keep_prob = tf.placeholder(tf.float32)
    h_fc1_drop = tf.nn.dropout(h_fc1, keep_prob)
    
    w_fc2 = weight_variable([1024, 10])
    b_fc2 = bias_variable([10])
    y_conv = tf.matmul(h_fc1_drop, w_fc2) + b_fc2
    
    cross_entropy = tf.reduce_mean(
            tf.nn.softmax_cross_entropy_with_logits(labels=y_, logits=y_conv))
    
    train_step = tf.train.AdamOptimizer(1e-4).minimize(cross_entropy)
    
    correct_prediction = tf.equal(tf.arg_max(y_, 1), tf.arg_max(y_conv, 1))
    accuracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))
    
    sess = tf.InteractiveSession()
    sess.run(tf.global_variables_initializer())
    
    for i in range(300000):
        batch = mnist.train.next_batch(50)
        
        if i % 100 == 0:
            train_accuracy = accuracy.eval(feed_dict={
                    x:batch[0], y_:batch[1], keep_prob:1.0})
            print("step %d train accuracy %g" % (i, train_accuracy))
        train_step.run(feed_dict={x:batch[0], y_:batch[1], keep_prob:0.5})
        

    print("test accuracy %g" % accuracy.eval(feed_dict={
            x:mnist.test.images, y_:mnist.test.labels, keep_prob:1.0}))
        


    
    

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