Trace operator

The trace operator Tr(A) of matrix A gives the sum of all of the diagonal entries of a matrix. The following example shows how to use a trace operator on tensor objects:

import tensorflow as tf

mat = tf.constant([
 [0, 1, 2],
 [3, 4, 5],
 [6, 7, 8]
], dtype=tf.float32)
 
 # get trace ('sum of diagonal elements') of the matrix
 mat = tf.trace(mat)
 
 with tf.Session() as sess:
    print(sess.run(mat))

The output of the listing is 12.0.