Multiple calls to generate_np ignore differences in kwargs

[Ian Goodfellow]

Quoting Nicolas Carlini:

attack = FastGradientMethod(model, sess)
adv_1 = attack.generate_np(test_data, eps=.5)
adv_2 = attack.generate_np(test_data, eps=.2)

will result in adv_1 == adv_2, a rather unexpected result.

This is because generate_np just stores one TensorFlow graph. It needs to have something like a dictionary mapping from argument values to graphs.

[Ian Goodfellow]

Alternately, generate_np could feed all the values of kwargs