MyMNISTsolution.py

# -*- coding: utf-8 -*-
"""
Created on Wed Jul  5 19:10:34 2017

@author: aakash.chotrani
"""

import tensorflow as tf

from tensorflow.examples.tutorials.mnist import input_data

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

n_nodes_hl1 = 500
n_nodes_hl2 = 500
n_nodes_hl3 = 500

n_classes = 10
batch_size = 100

x = tf.placeholder('float',[None,784])
y = tf.placeholder('float')

def neural_network_model(data):
    hidden_1_layer ={'weights': tf.Variable(tf.random_normal([784,n_nodes_hl1])),
                     'biases':tf.Variable(tf.random_normal([n_nodes_hl1]))}
    
    hidden_2_layer ={'weights': tf.Variable(tf.random_normal([n_nodes_hl1,n_nodes_hl2])),
                     'biases':tf.Variable(tf.random_normal([n_nodes_hl2]))}
    
    hidden_3_layer ={'weights': tf.Variable(tf.random_normal([n_nodes_hl2,n_nodes_hl3])),
                     'biases':tf.Variable(tf.random_normal([n_nodes_hl3]))}
    
    output_layer ={'weights': tf.Variable(tf.random_normal([n_nodes_hl3,n_classes])),
                     'biases':tf.Variable(tf.random_normal([n_classes]))}
    
    #(input_data*weights) + biases
    l1 = tf.add(tf.matmul(data,hidden_1_layer['weights']),hidden_1_layer['biases'])#input goes through the sum box
    l1 = tf.nn.relu(l1)#rectified linear is activation function applied to layer 1
    
    l2 = tf.add(tf.matmul(l1,hidden_2_layer['weights']),hidden_2_layer['biases'])#input goes through the sum box
    l2 = tf.nn.relu(l1)#rectified linear is activation function applied to layer 2
    
    l3 = tf.add(tf.matmul(l2,hidden_3_layer['weights']),hidden_3_layer['biases'])#input goes through the sum box
    l3 = tf.nn.relu(l3)#rectified linear is activation function applied to layer 3
    
    
    output = tf.matmul(l3,output_layer['weights']) + output_layer['biases']
    
    
    return output


def train_neural_network(x):
    prediction = neural_network_model(x)
    cost = tf.reduce_mean(tf.nn.softmax_cross_entropy_with_logits(logits = prediction,labels = y))
    optimizer = tf.train.AdamOptimizer().minimize(cost)
    
    #cycles of feed forward and back propagation
    hm_epochs = 10
    with tf.Session() as sess:
        sess.run(tf.global_variables_initializer())
        
        for epoch in range(hm_epochs):
            epoch_loss = 0
            for _ in range(int(mnist.train.num_examples/batch_size)):
                epoch_x,epoch_y = mnist.train.next_batch(batch_size)
                _,c = sess.run([optimizer,cost],feed_dict = {x: epoch_x,y: epoch_y})
                epoch_loss += c
            print('Epoch',epoch,'completed out of', hm_epochs,'loss:',epoch_loss)
        correct = tf.equal(tf.arg_max(prediction,1),tf.argmax(y,1))
        
        accuracy = tf.reduce_mean(tf.cast(correct,'float'))
        print('Accuracy: ',accuracy.eval({x:mnist.test.images,y:mnist.test.labels}))
        
        
train_neural_network(x)