# Copyright 2018 The KaiJIN Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
from torch import optim


def PolyLR(optimizer, power, max_iters, last_epoch=-1, **kwargs):
  return optim.lr_scheduler.LambdaLR(
      optimizer,
      lr_lambda=lambda epoch: (1 - epoch/float(max_iters)) ** float(power),
      last_epoch=last_epoch)