Check if NaN in Tensorflow

Question

I would like to check a tensorflow variable and set it to zero if it is NaN.

How can I do this? The following trick seems not to work:

if tf.is_nan(v) is True:
    v = 0.0

Answer 1

If v is a 0d tensor, you might use tf.where to test and update the value:

import numpy as np

v = tf.constant(np.nan)                  # initialize a variable as nan  ​
v = tf.where(tf.is_nan(v), 0., v)
​
with tf.Session() as sess:    
    print(sess.run(v))

# 0.0

Answer 2

For Tensorflow 2.0

you can you:

import tensorflow as tf

if tf.math.is_nan(v):
    print("v is NaN")

or with numpy

import numpy as np

if np.is_nan(v):
    print("v is NaN")