tensorflow的Session

#coding=utf-8
import tensorflow as tf

a = tf.add(2, 5)
b = tf.multiply(a, 3)

sess = tf.Session()
# sess.run(b)

sess.run(tf.global_variables_initializer())

replace_dict = {a: 15}
sess.run(b, feed_dict = replace_dict)

c = tf.constant(5)
with sess.as_default():
    a.eval()

sess.close()