github : mnist_logistic_regression with Tensorflow

mnist_logistic_regression

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

reproducibility

tf.set_random_seed(777)

mnist = input_data.read_data_sets("./data", one_hot=True)

Successfully downloaded train-images-idx3-ubyte.gz 9912422 bytes.
Extracting ./data\train-images-idx3-ubyte.gz
Successfully downloaded train-labels-idx1-ubyte.gz 28881 bytes.
Extracting ./data\train-labels-idx1-ubyte.gz
Successfully downloaded t10k-images-idx3-ubyte.gz 1648877 bytes.
Extracting ./data\t10k-images-idx3-ubyte.gz
Successfully downloaded t10k-labels-idx1-ubyte.gz 4542 bytes.
Extracting ./data\t10k-labels-idx1-ubyte.gz

parameters

learning_rate = 0.001
training_epochs = 15
batch_size = 100

Input placeholders

X = tf.placeholder(tf.float32, shape = [None, 28*28], name = "X")
Y = tf.placeholder(tf.float32, shape = [None, 10], name = "Y")

Weight & bias for nn layers

W = tf.get_variable(name = "weights", initializer=tf.random_normal([784, 10]))
b = tf.get_variable(name = "bias", initializer=tf.random_normal([10]))

hypothesis

hypothesis = tf.matmul(X,W) + b

loss & optimizer

loss = tf.reduce_mean(tf.nn.softmax_cross_entropy_with_logits(logits=hypothesis, labels=Y))
optimizer = tf.train.AdamOptimizer(learning_rate = learning_rate).minimize(loss)

Initialize

The first is the allow_growth option, which attempts to allocate only as much GPU memory based on runtime allocations: it starts out allocating very little memory, and as Sessions get run and more GPU memory is needed, we extend the GPU memory region needed by the TensorFlow process. Note that we do not release memory, since that can lead to even worse memory fragmentation.

sess = tf.Session(config=tf.ConfigProto(gpu_options = tf.GPUOptions(allow_growth = True)))
sess.run(tf.global_variables_initializer())

Train model

for epoch in range(training_epochs):
    avg_loss = 0
    total_batch = int(mnist.train.num_examples / batch_size)
    
    for i in range(total_batch):
        batch_xs, batch_ys = mnist.train.next_batch(batch_size)
        _, _loss = sess.run([optimizer, loss], feed_dict = {X:batch_xs, Y:batch_ys})
        avg_loss += _loss / total_batch
     
    print("Epoch : {}, loss : {:.9f}".format(epoch+1, avg_loss))
print("Learning Finished")

Epoch : 1, loss : 0.385825345
Epoch : 2, loss : 0.376512970
Epoch : 3, loss : 0.367820557
Epoch : 4, loss : 0.361098582
Epoch : 5, loss : 0.354843884
Epoch : 6, loss : 0.348474874
Epoch : 7, loss : 0.343070328
Epoch : 8, loss : 0.337118507
Epoch : 9, loss : 0.332395571
Epoch : 10, loss : 0.328015425
Epoch : 11, loss : 0.323890320
Epoch : 12, loss : 0.319517709
Epoch : 13, loss : 0.315231980
Epoch : 14, loss : 0.312611983
Epoch : 15, loss : 0.308055050
Learning Finished

Test model and check accuracy

correct_prediction = tf.equal(tf.argmax(hypothesis, 1), tf.argmax(Y, 1))
accruracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))
print("Accuracy : ", sess.run(accruracy, feed_dict = {X:mnist.test.images, Y:mnist.test.labels}))

Accuracy :  0.9153

r = random.randint(0, mnist.test.num_examples - 1)
print("Label: ", sess.run(tf.argmax(mnist.test.labels[r:r + 1], 1)))
print("Prediction: ", sess.run(
    tf.argmax(hypothesis, 1), feed_dict={X: mnist.test.images[r:r + 1]}))

Label:  [7]
Prediction:  [7]