tf_computation_graph_p1.py

import tensorflow as tf
import numpy as np

# phase 1: define computation graph f
pi = tf.constant(np.pi)
one = tf.constant(1.)
# both one and pi must be of same datatype
f = tf.add(pi,one)

# phase 2: execute computation graph f
with tf.Session() as sess:
    print sess.run(f)