import tensorflow as tf

############
# CONSTANT #
############

# Use variable_scope to modify names of all tensors in block.
with tf.variable_scope("test"):
    # First constant.
    a = tf.constant(1, name="a")

    # Second constant.
    b = tf.constant(5, name="b")

    # Print names of our two constants.
    print(a.name)
    print(b.name)

    # We want to add 2 constants together.
    z = a + b

    # Run TensorFlow and solve for Z.
    result = tf.Session().run(z)
    print(result)

################
# PLACEHOLDERS #
################

# Two constants.
a = tf.constant(5)
b = tf.constant(10)

# Use placeholder to insert values into TensorFlow from Python code.
c = tf.placeholder(tf.int32)

# Add the two constants.
# ... Then subtract the input value we use for the placeholder.
z = a + b - c

# Run TensorFlow.
# ... Use the value 5 for the placeholder C.
result = tf.Session().run(z, {c: 2})
# This is 5 plus 10 minus 2.
print(result)


###########
# DROPOUT #
###########

x = [1., 2., 1., 4., 1.]

# Compute dropout on our tensor.
result = tf.nn.dropout(x, 0.75)
session = tf.Session()
print(session.run(result))