Last active
June 28, 2019 17:12
-
-
Save hussius/1534135a419bb0b957b9 to your computer and use it in GitHub Desktop.
Toy example of single-layer autoencoder in TensorFlow
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
import tensorflow as tf | |
import numpy as np | |
import math | |
#import pandas as pd | |
#import sys | |
input = np.array([[2.0, 1.0, 1.0, 2.0], | |
[-2.0, 1.0, -1.0, 2.0], | |
[0.0, 1.0, 0.0, 2.0], | |
[0.0, -1.0, 0.0, -2.0], | |
[0.0, -1.0, 0.0, -2.0]]) | |
# Code here for importing data from file | |
noisy_input = input + .2 * np.random.random_sample((input.shape)) - .1 | |
output = input | |
# Scale to [0,1] | |
scaled_input_1 = np.divide((noisy_input-noisy_input.min()), (noisy_input.max()-noisy_input.min())) | |
scaled_output_1 = np.divide((output-output.min()), (output.max()-output.min())) | |
# Scale to [-1,1] | |
scaled_input_2 = (scaled_input_1*2)-1 | |
scaled_output_2 = (scaled_output_1*2)-1 | |
input_data = scaled_input_2 | |
output_data = scaled_output_2 | |
# Autoencoder with 1 hidden layer | |
n_samp, n_input = input_data.shape | |
n_hidden = 2 | |
x = tf.placeholder("float", [None, n_input]) | |
# Weights and biases to hidden layer | |
Wh = tf.Variable(tf.random_uniform((n_input, n_hidden), -1.0 / math.sqrt(n_input), 1.0 / math.sqrt(n_input))) | |
bh = tf.Variable(tf.zeros([n_hidden])) | |
h = tf.nn.tanh(tf.matmul(x,Wh) + bh) | |
# Weights and biases to hidden layer | |
Wo = tf.transpose(Wh) # tied weights | |
bo = tf.Variable(tf.zeros([n_input])) | |
y = tf.nn.tanh(tf.matmul(h,Wo) + bo) | |
# Objective functions | |
y_ = tf.placeholder("float", [None,n_input]) | |
cross_entropy = -tf.reduce_sum(y_*tf.log(y)) | |
meansq = tf.reduce_mean(tf.square(y_-y)) | |
train_step = tf.train.GradientDescentOptimizer(0.05).minimize(meansq) | |
init = tf.initialize_all_variables() | |
sess = tf.Session() | |
sess.run(init) | |
n_rounds = 5000 | |
batch_size = min(50, n_samp) | |
for i in range(n_rounds): | |
sample = np.random.randint(n_samp, size=batch_size) | |
batch_xs = input_data[sample][:] | |
batch_ys = output_data[sample][:] | |
sess.run(train_step, feed_dict={x: batch_xs, y_:batch_ys}) | |
if i % 100 == 0: | |
print i, sess.run(cross_entropy, feed_dict={x: batch_xs, y_:batch_ys}), sess.run(meansq, feed_dict={x: batch_xs, y_:batch_ys}) | |
print "Target:" | |
print output_data | |
print "Final activations:" | |
print sess.run(y, feed_dict={x: input_data}) | |
print "Final weights (input => hidden layer)" | |
print sess.run(Wh) | |
print "Final biases (input => hidden layer)" | |
print sess.run(bh) | |
print "Final biases (hidden layer => output)" | |
print sess.run(bo) | |
print "Final activations of hidden layer" | |
print sess.run(h, feed_dict={x: input_data}) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
how to view the reconstructed input?