test_nnet.py 文件源码

def test_local_softmax_grad_optimization_and_big_input(self):
        """Test the Logsoftmax's grad substitution.

        Check that Log(Softmax(x))'s grad is substituted with Logsoftmax(x)'s
        grad and that the new operation does not explode for big inputs.
        Note that only the grad is checked.
        """
        m = theano.config.mode
        m = theano.compile.get_mode(m)
        m.check_isfinite = False
        # some inputs that are large to make the gradient explode in the non
        # optimized case
        a = numpy.exp(
            10 * numpy.random.rand(5, 10).astype(theano.config.floatX))

        def myfunc(x):
            sm = tensor.nnet.softmax(x)
            logsm = tensor.log(sm)
            return logsm
        # We set step to 0.1 because for big values we need a big epsilon
        utt.verify_grad(myfunc, [a], eps=0.1, mode=m)
        sa = theano.shared(a)
        f = theano.function([], myfunc(sa))
        self.assertTrue(check_stack_trace(f, ops_to_check='all'))