theano - print value of TensorVariable
For future readers: the previous answer is quite good. But, I found the 'tag.test_value' mechanism more beneficial for debugging purposes (see theano-debug-faq):
from theano import config
from theano import tensor as T
config.compute_test_value = 'raise'
import numpy as np
#define a variable, and use the 'tag.test_value' option:
x = T.matrix('x')
x.tag.test_value = np.random.randint(100,size=(5,5))
#define how y is dependent on x:
y = x*x
#define how some other value (here 'errorCount') depends on y:
errorCount = T.sum(y)
#print the tag.test_value result for debug purposes!
errorCount.tag.test_value
For me, this is much more helpful; e.g., checking correct dimensions etc.
If y is a theano variable, y.shape will be a theano variable. so it is normal that
print y.shape
return:
Shape.0
If you want to evaluate the expression y.shape, you can do:
y.shape.eval()
if y.shape
do not input to compute itself(it depend only on shared variable and constant). Otherwise, if y
depend on the x
Theano variable you can pass the inputs value like this:
y.shape.eval(x=numpy.random.rand(...))
this is the same thing for the sum
. Theano graph are symbolic variable that do not do computation until you compile it with theano.function
or call eval()
on them.
EDIT: Per the docs, the syntax in newer versions of theano is
y.shape.eval({x: numpy.random.rand(...)})