'Derivative of the generator cost wrt. y_noise.'

def bprop_generator(self, y_noise):

    if (self.func == 'original'):
        return (self.scale / (y_noise - 1.0))
    elif (self.func == 'modified'):
        return ((- self.scale) / y_noise)
    elif (self.func == 'wasserstein'):
        return (self.scale * self.one_buf)
