Tell whether an expression is deterministic, ie it does not use a random number generator.

theanodeter.py

import theano, theano.tensor as T
from theano.tensor.shared_randomstreams import RandomStreams


def theano_expr_bfs(expr):
    stack = [expr]
    while True:
        if not stack:
            break
        expr = stack.pop()
        stack += expr.owner.inputs if hasattr(expr.owner, 'inputs') else []
        yield expr


def tell_deterministic(expr):
    return all(not hasattr(i, 'rng') for i in theano_expr_bfs(expr))


if __name__ == '__main__':
  print tell_deterministic(T.matrix())

  rng = RandomStreams()
  inpt = T.vector()
  samples = rng.normal(size=inpt.shape)
  expr = inpt + samples
  print tell_deterministic(expr)