[VX] Tensorflow-Fun: Build Fibonacci Series using Tensorflow

fab-pure.py

# Pure TF implm.
# Fibonacci series using tensorflow
import tensorflow as tf
import numpy as np
import time

def build_graph2(max_count):
	init = np.zeros([max_count], dtype=int)
	m0 = tf.Variable(init,dtype=tf.int32)
	i0 = tf.constant(2)
	cond = lambda i, op: i<max_count
	body = lambda i, op: [i+1, tf.assign(m0[i], m0[i-1]+m0[i-2])]
	loop = tf.while_loop(cond, body, loop_vars=[i0, m0])
	return loop

def build_graph(max_count):
	m0 = tf.constant([0, 1])
	i0 = tf.constant(2)
	cond = lambda i, m: tf.less(i, max_count)
	body = lambda i, m: [tf.add(i, 1), tf.concat([m, [m[i-1] + m[i-2]]], 0)]
	loop = tf.while_loop(cond, body, 
		loop_vars=[i0, m0],
		shape_invariants=[i0.get_shape(), tf.TensorShape([None])])
	return loop

def build_series(sess, max_count):
	loop = build_graph(max_count)
	sess.run(tf.global_variables_initializer())
	now = time.time()
	i, out = sess.run(loop)
	print(time.time() - now)
	return out

def fab_cpu(count):
	now = time.time()
	series = np.zeros([count], dtype=int); series[1] = 1
	for i in range(2, count):
		series[i] = series[i-1] + series[i-2]
	print(time.time() - now)

if __name__ == '__main__':
	sess = tf.InteractiveSession()
	build_series(sess, 10000)
	fab_cpu(10000)

fab.py

# Fibonacci series using tensorflow
import tensorflow as tf
import numpy as np

def build_graph(max_count):
	init = np.zeros([max_count], dtype=np.int64); init[1] = 1
	series = tf.Variable(init)
	idx = tf.placeholder(dtype=tf.int32, shape=None)
	first_last = series[idx-1]
	second_last = series[idx-2]
	new_val = tf.add(first_last, second_last)
	step = tf.assign(series[idx], new_val)
	return idx, step, series

def build_series(sess, max_count):
	idx, step, series = build_graph(max_count)
	sess.run(tf.global_variables_initializer())
	for i in range(2, max_count): 
		sess.run(step, {idx: i})
	return sess.run(series)

if __name__ == '__main__':
	sess = tf.InteractiveSession()
	print(build_series(sess, 10))