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@drheart @weijian001 @aymericdamien
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""" K-Means.
Implement K-Means algorithm with TensorFlow, and apply it to classify
handwritten digit images. This example is using the MNIST database of
handwritten digits as training samples (http://yann.lecun.com/exdb/mnist/).
Note: This example requires TensorFlow v1.1.0 or over.
Author: Aymeric Damien
Project: https://github.com/aymericdamien/TensorFlow-Examples/
"""
from __future__ import print_function
import numpy as np
import tensorflow as tf
from tensorflow.contrib.factorization import KMeans
# Ignore all GPUs, tf k-means does not benefit from it.
import os
os.environ["CUDA_VISIBLE_DEVICES"] = ""
# Import MNIST data
from tensorflow.examples.tutorials.mnist import input_data
mnist = input_data.read_data_sets("/tmp/data/", one_hot=True)
full_data_x = mnist.train.images
# Parameters
num_steps = 50 # Total steps to train
batch_size = 1024 # The number of samples per batch
k = 25 # The number of clusters
num_classes = 10 # The 10 digits
num_features = 784 # Each image is 28x28 pixels
# Input images
X = tf.placeholder(tf.float32, shape=[None, num_features])
# Labels (for assigning a label to a centroid and testing)
Y = tf.placeholder(tf.float32, shape=[None, num_classes])
# K-Means Parameters
kmeans = KMeans(inputs=X, num_clusters=k, distance_metric='cosine',
use_mini_batch=True)
# Build KMeans graph
training_graph = kmeans.training_graph()
if len(training_graph) > 6: # Tensorflow 1.4+
(all_scores, cluster_idx, scores, cluster_centers_initialized,
cluster_centers_var, init_op, train_op) = training_graph
else:
(all_scores, cluster_idx, scores, cluster_centers_initialized,
init_op, train_op) = training_graph
cluster_idx = cluster_idx[0] # fix for cluster_idx being a tuple
avg_distance = tf.reduce_mean(scores)
# Initialize the variables (i.e. assign their default value)
init_vars = tf.global_variables_initializer()
# Start TensorFlow session
sess = tf.Session()
# Run the initializer
sess.run(init_vars, feed_dict={X: full_data_x})
sess.run(init_op, feed_dict={X: full_data_x})
# Training
for i in range(1, num_steps + 1):
_, d, idx = sess.run([train_op, avg_distance, cluster_idx],
feed_dict={X: full_data_x})
if i % 10 == 0 or i == 1:
print("Step %i, Avg Distance: %f" % (i, d))
# Assign a label to each centroid
# Count total number of labels per centroid, using the label of each training
# sample to their closest centroid (given by 'idx')
counts = np.zeros(shape=(k, num_classes))
for i in range(len(idx)):
counts[idx[i]] += mnist.train.labels[i]
# Assign the most frequent label to the centroid
labels_map = [np.argmax(c) for c in counts]
labels_map = tf.convert_to_tensor(labels_map)
# Evaluation ops
# Lookup: centroid_id -> label
cluster_label = tf.nn.embedding_lookup(labels_map, cluster_idx)
# Compute accuracy
correct_prediction = tf.equal(cluster_label, tf.cast(tf.argmax(Y, 1), tf.int32))
accuracy_op = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))
# Test Model
test_x, test_y = mnist.test.images, mnist.test.labels
print("Test Accuracy:", sess.run(accuracy_op, feed_dict={X: test_x, Y: test_y}))
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