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Paddle/python/paddle/fluid/contrib/slim/prune/pruner.py

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# Copyright (c) 2018 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.
import numpy as np
from .... import layers
__all__ = ['Pruner', 'MagnitudePruner', 'RatioPruner']
class Pruner(object):
"""
Base class of all pruners.
"""
def __init__(self):
pass
def prune(self, param):
pass
class MagnitudePruner(Pruner):
"""
Pruner used to pruning a parameter by threshold.
"""
def __init__(self, threshold):
self.threshold = threshold
def prune(self, param, threshold=None):
if threshold is None:
thres = layers.fill_constant(
shape=[1], dtype='float32', value=self.threshold)
else:
thres = threshold
zeros_mask = layers.less_than(x=param, y=thres)
return zeros_mask
class RatioPruner(Pruner):
"""
Pruner used to pruning a parameter by ratio.
"""
def __init__(self, ratios=None):
"""
Args:
ratios: dict with pair (paramer_name, pruned_ratio).
"""
self.ratios = ratios
def prune(self, param, ratio=None):
"""
Args:
ratio: `ratio=40%` means pruning (1 - 40%) weights to zero.
"""
if ratio is None:
rat = self.ratios[
param.name] if param.name in self.ratios else self.ratios['*']
else:
rat = ratio
if rat < 1.0:
k = max(int(rat * np.prod(param.shape)), 1)
param_vec = layers.reshape(x=param, shape=[1, -1])
param_topk, _ = layers.topk(param_vec, k=k)
threshold = layers.slice(
param_topk, axes=[1], starts=[-1], ends=[k])
threshold = layers.reshape(x=threshold, shape=[1])
zeros_mask = layers.less_than(x=param, y=threshold)
else:
zeros_mask = layers.ones(param.shape)
return zeros_mask