'Call to schedule current learning rate.
Parameters
iteration: int
Current iteration count.'

def __call__(self, iteration):

    if (not self.init):
        self.init = True
        self.old_lr = self.base_lr
    lr = (self.base_lr * math.pow(self.factor, int((iteration / self.step))))
    if (lr != self.old_lr):
        self.old_lr = lr
        logging.info('At    Iteration    [%d]:    Swith    to    new    learning    rate    %.5f', iteration, lr)
    return lr
