Udacity Self-Driving Car Engineer Nanodegree: Introduction to TensorFlow
# Convert the following to TensorFlow:
x = tf.constant(10)
y = tf.constant(2)
z = tf.subtract(tf.divide(x,y),tf.cast(tf.constant(1), tf.float64))
with tf.Session() as sess:
output = sess.run(z)
print(output)
def batches(batch_size, features, labels):
"""
Create batches of features and labels
:param batch_size: The batch size
:param features: List of features
:param labels: List of labels
:return: Batches of (Features, Labels)
"""
assert len(features) == len(labels)
outout_batches = []
sample_size = len(features)
for start_i in range(0, sample_size, batch_size):
end_i = start_i + batch_size
batch = [features[start_i:end_i], labels[start_i:end_i]]
outout_batches.append(batch)
return outout_batches
# Features and Labels
features = tf.placeholder(tf.float32, [None, n_input])
labels = tf.placeholder(tf.float32, [None, n_classes])
# Weights & bias
weights = tf.Variable(tf.random_normal([n_input, n_classes]))
bias = tf.Variable(tf.random_normal([n_classes]))
# Logits - xW + b
logits = tf.add(tf.matmul(features, weights), bias)
# Define loss and optimizer
cost = tf.reduce_mean(tf.nn.softmax_cross_entropy_with_logits(logits=logits, labels=labels))
optimizer = tf.train.GradientDescentOptimizer(learning_rate=learning_rate).minimize(cost)
# Calculate accuracy
correct_prediction = tf.equal(tf.argmax(logits, 1), tf.argmax(labels, 1))
accuracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))
batch_size = 128
init = tf.global_variables_initializer()
with tf.Session() as sess:
sess.run(init)
# TODO: Train optimizer on all batches
for batch_features, batch_labels in batches(batch_size, train_features, train_labels):
sess.run(optimizer, feed_dict={features: batch_features, labels: batch_labels})
# Calculate accuracy for test dataset
test_accuracy = sess.run(
accuracy,
feed_dict={features: test_features, labels: test_labels})