Describe how to use tensorflow to save model, parameters, inputs and outputs

tf_save.py

import tensorflow as tf

tf.GraphKeys.USEFUL = 'useful'

v1 = tf.placeholder(tf.float32, name="v1")
v2 = tf.placeholder(tf.float32, name="v2")
v3 = tf.mul(v1, v2)
vx = tf.Variable(10.0, name="vx")
v4 = tf.add(v3, vx, name="v4")

tf.add_to_collection(tf.GraphKeys.USEFUL, v1)
tf.add_to_collection(tf.GraphKeys.USEFUL, v2)
tf.add_to_collection(tf.GraphKeys.USEFUL, v4)

saver = tf.train.Saver([vx])
sess = tf.Session()
sess.run(tf.initialize_all_variables())
sess.run(vx.assign(tf.add(vx, vx)))
result = sess.run(v4, feed_dict={v1:12.0, v2:3.3})
print(result)
saver.save(sess, "./model_ex1")