tf_cook_02_01.py

import numpy as np
import tensorflow as tf


x_vals = np.array([1., 3., 5., 7., 9.])

# Create the TensorFlow Placceholder
x_data = tf.placeholder(tf.float32)

# Constant for multilication
m = tf.constant(3.)

prod = tf.multiply(x_data, m)
for x_val in x_vals:
    print(sess.run(prod, feed_dict={x_data: x_val}))
>3.0
>9.0
>15.0
>21.0
>27.0