# Copyright (c) 2020 PaddlePaddle 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.
__all__ = ["SchedulerBase", "Constant", "PieceWise", "StepWise"]
[docs]class SchedulerBase(object):
def __call__(self, step):
raise NotImplementedError("You should implement the __call__ method.")
[docs]class Constant(SchedulerBase):
def __init__(self, value):
self.value = value
def __call__(self, step):
return self.value
[docs]class PieceWise(SchedulerBase):
def __init__(self, anchors):
anchors = list(anchors)
anchors = sorted(anchors, key=lambda x: x[0])
assert anchors[0][0] == 0, "it must start from zero"
self.xs = [item[0] for item in anchors]
self.ys = [item[1] for item in anchors]
self.num_anchors = len(self.xs)
def __call__(self, step):
i = 0
for x in self.xs:
if step >= x:
i += 1
if i == 0:
return self.ys[0]
if i == self.num_anchors:
return self.ys[-1]
k = (self.ys[i] - self.ys[i - 1]) / (self.xs[i] - self.xs[i - 1])
out = self.ys[i - 1] + (step - self.xs[i - 1]) * k
return out
[docs]class StepWise(SchedulerBase):
def __init__(self, anchors):
anchors = list(anchors)
anchors = sorted(anchors, key=lambda x: x[0])
assert anchors[0][0] == 0, "it must start from zero"
self.xs = [item[0] for item in anchors]
self.ys = [item[1] for item in anchors]
self.num_anchors = len(self.xs)
def __call__(self, step):
i = 0
for x in self.xs:
if step >= x:
i += 1
if i == self.num_anchors:
return self.ys[-1]
if i == 0:
return self.ys[0]
return self.ys[i - 1]