test_autograd.py

# Filename: test_autograd.py
# Description: Test autograd's limits.
# Author: Pushpendre Rastogi
# Created: Mon Apr 13 18:36:26 2015 (-0400)
# Last-Updated:
#           By:
#     Update #: 42
import autograd.numpy as np
from autograd import grad
from autograd.util import quick_grad_check

def assignment(y, x):
    for i in range(3):
        x['a'] = np.sum(np.array([y[i], x['a']]))
    return x['a']

def test_assignment():
    x = dict(a=1)
    f = lambda y : assignment(y, x)
    y = np.random.rand(3,1)
    print f(y)
    gradf = grad(f)
    print gradf(y) # Works !
    try:
        print gradf(y) # Fails !!
    except:
        print "fail"    
    print gradf(y) # Works again !!!
    return

if __name__ == "__main__":
    test_assignment()