theano - print value of TensorVariable

Question

How can I print the numerical value of a theano TensorVariable? I\'m new to theano, so please be patient :)

I have a function where I get y

Answer 1

Use theano.printing.Print to add print operator to your computational graph.

Example:

import numpy
import theano

x = theano.tensor.dvector('x')

x_printed = theano.printing.Print('this is a very important value')(x)

f = theano.function([x], x * 5)
f_with_print = theano.function([x], x_printed * 5)

#this runs the graph without any printing
assert numpy.all( f([1, 2, 3]) == [5, 10, 15])

#this runs the graph with the message, and value printed
assert numpy.all( f_with_print([1, 2, 3]) == [5, 10, 15])

Output:

this is a very important value __str__ = [ 1. 2. 3.]

Source: Theano 1.0 docs: “How do I Print an Intermediate Value in a Function?”