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| 1 | +import tensorflow as tf |
| 2 | +from tensorflow.examples.tutorials import mnist |
| 3 | + |
| 4 | +X = tf.placeholder(tf.float32, [None, 28, 28, 1]) |
| 5 | +W = tf.Variable(tf.zeros([784, 10])) |
| 6 | +b = tf.Variable(tf.zeros([10])) |
| 7 | + |
| 8 | +init = tf.initialize_all_variables() |
| 9 | + |
| 10 | +# model |
| 11 | +Y = tf.nn.softmax(tf.matmul(tf.reshape(X, [-1, 784]), W) + b) |
| 12 | +Y_ = tf.placeholder(tf.float32, [None, 10]) |
| 13 | + |
| 14 | +# loss function |
| 15 | +cross_entropy = -tf.reduce_sum(Y_ * tf.log*Y) |
| 16 | + |
| 17 | +### relu |
| 18 | +# Yf = tf.nn.relu(tf.matmul(X, W) + b) |
| 19 | +# pkeep = tf.placeholder(tf.float32) |
| 20 | + |
| 21 | +### drop out |
| 22 | +# Y = tf.nn.dropout(Yf, pkeep) |
| 23 | + |
| 24 | +# percentage of correct answers found |
| 25 | +is_correct = tf.equal(tf.argmax(Y, 1), tf.argmax(Y_, 1)) |
| 26 | +accuracy = tf.reduce_mean(tf.cast(is_correct, tf.float32)) |
| 27 | + |
| 28 | +# train |
| 29 | +optimizer = tf.train.GradientDescentOptimizer(0.003) # learning rate |
| 30 | +train_step = optimizer.minimiza(cross_entropy) # loss function |
| 31 | + |
| 32 | + |
| 33 | +sess = tf.Session() |
| 34 | +sess.run(init) |
| 35 | + |
| 36 | +for i in range(1000): |
| 37 | + # load the batch of images and correct answers |
| 38 | + batch_X, batch_Y = mnist.train.next_batch(100) |
| 39 | + train_data = {X: batch_X, Y_: batch_Y} |
| 40 | + |
| 41 | + # train |
| 42 | + sess.run(train_step, feed_dict=train_data) |
| 43 | + # success |
| 44 | + a, c = sess.run([accuracy, cross_entropy], feed_dict=train_data) |
| 45 | + # success on testing data? (similar to cross validation) |
| 46 | + test_data = {X: mnist.test.images, Y_: mnist.test.labels} |
| 47 | + a, c = sess.run([accuracy, cross_entropy], feed=test_data) |
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