TF:TF下CNN实现mnist数据集预测 96%采用placeholder用法+2层C及其max_pool法+隐藏层dropout法+输出层softmax法+目标函数cross_entropy法+AdamOptimizer算法
目录
后期更新……
- import tensorflow as tf
- from tensorflow.examples.tutorials.mnist import input_data
- number 1 to 10 data
- mnist = input_data.read_data_sets('MNIST_data', one_hot=True)
-
- def compute_accuracy(v_xs, v_ys):
- global prediction
- y_pre = sess.run(prediction, feed_dict={xs: v_xs, keep_prob: 1})
- correct_prediction = tf.equal(tf.argmax(y_pre,1), tf.argmax(v_ys,1))
- accuracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))
- result = sess.run(accuracy, feed_dict={xs: v_xs, ys: v_ys, keep_prob: 1})
- return result
-
- def weight_variable(shape):
- initial = tf.truncated_normal(shape, stddev=0.1)
- return tf.Variable(initial)
- def bias_variable(shape):
- initial = tf.constant(0.1, shape=shape) return tf.Variable(initial)
-
- def conv2d(x, W):
- return tf.nn.conv2d(x, W, strides=[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')
-
- xs = tf.placeholder(tf.float32, [None, 784]) 28x28
- ys = tf.placeholder(tf.float32, [None, 10])
- keep_prob = tf.placeholder(tf.float32)
- x_image = tf.reshape(xs, [-1, 28, 28, 1])
-
- conv1 layer;
- 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)
- h_fc1_drop = tf.nn.dropout(h_fc1, keep_prob)
-
- W_fc2 = weight_variable([1024, 10])
- b_fc2 = bias_variable([10])
- prediction = tf.nn.softmax(tf.matmul(h_fc1_drop, W_fc2) + b_fc2)
-
- the error between prediction and real data
- cross_entropy = tf.reduce_mean(-tf.reduce_sum(ys * tf.log(prediction),
- reduction_indices=[1]))
- train_step = tf.train.AdamOptimizer(1e-4).minimize(cross_entropy)
-
- sess = tf.Session()
- important step
- sess.run(tf.global_variables_initializer())
-
- for i in range(10):
- batch_xs, batch_ys = mnist.train.next_batch(100)
- sess.run(train_step, feed_dict={xs: batch_xs, ys: batch_ys, keep_prob: 0.5})
- if i % 50 == 0:
- print(compute_accuracy(
- mnist.test.images, mnist.test.labels))
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