tf.matmul-cpu.py

import os
import numpy as np
import tensorflow as tf
import time

# this tells CUDA to ignore all available devices
os.environ['TF_CPP_MIN_LOG_LEVEL'] = '3'
# set log level
os.environ['CUDA_VISIBLE_DEVICES'] = '-1'

# confirm a GPU is found or ignored
if tf.test.gpu_device_name():
        print("GPU found")
else:
        print("Tensorflow is using only CPUs.")

# create a random matrix
numpy_start = time.time()
a = np.random.rand(10000, 70000)
print("Numpy generated a random 10000x70000 matrix, matrix a.")
# create a second random matrix
b = np.random.rand(70000, 10000)
numpy_end = time.time()
print("Numpy generated a random 70000x10000 matrix, matrix b.")

# tell me how much time it took to generate the matrices
print("It took numpy", numpy_end-numpy_start, "seconds to generate matrices a and b.")

# start matmul; record start and end times
print("Tensorflow is beginning matrix multiplication.")
tf_start = time.time()
c = tf.matmul(a,b)
tf_end  = time.time()

# tell me how much time it took to multiply the matrices
print("Tensorflow multiplied matrices a and b in", tf_end-tf_start, "seconds.")