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Paddle/python/paddle/v2/fluid/clip.py

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# Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserve.
#
#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 functools
import layers
from . import core
__all__ = [
'GradientClipByValue',
'ErrorClipByValue',
'append_gradient_clip_ops',
'error_clip_callback',
]
class BaseErrorClipAttr(object):
def append_clip_op(self, block, grad_name):
raise NotImplementedError()
class ErrorClipByValue(BaseErrorClipAttr):
def __init__(self, max, min=None):
max = float(max)
if min is None:
min = -max
else:
min = float(min)
self.max = max
self.min = min
def append_clip_op(self, block, grad_name):
clip_op_desc = block.desc.append_op()
clip_op_desc.set_type("clip")
clip_op_desc.set_input("X", [grad_name])
clip_op_desc.set_output("Out", [grad_name])
clip_op_desc.set_attr("min", self.min)
clip_op_desc.set_attr("max", self.max)
def error_clip_callback(block, context):
# the context is a grad_to_var map
grad_to_var = context
op_desc = block.desc.op(block.desc.op_size() - 1)
for grad_n in filter(lambda n: grad_to_var.has_key(n),
op_desc.output_arg_names()):
fwd_var = block.var_recursive(grad_to_var[grad_n])
error_clip = getattr(fwd_var, "error_clip", None)
if not (error_clip is None or isinstance(error_clip,
BaseErrorClipAttr)):
raise TypeError(
"Variable's error_clip should be an instance of BaseErrorClipAttr or None."
)
if error_clip is not None:
error_clip.append_clip_op(block, grad_n)
class BaseGradientClipAttr(object):
def process_context(self, context, p_g):
raise NotImplementedError()
def create_operators(self, param, grad):
raise NotImplementedError()
class NullGradientClipAttr(BaseGradientClipAttr):
def process_context(self, context, p_g):
pass
def create_operators(self, param, grad):
return param, grad
class GradientClipByValue(BaseGradientClipAttr):
def __init__(self, max, min=None):
max = float(max)
if min is None:
min = -max
else:
min = float(min)
self.max = max
self.min = min
def process_context(self, context, p_g):
pass
def create_operators(self, param, grad):
new_grad = layers.clip(x=grad, min=self.min, max=self.max)
return param, new_grad
def append_gradient_clip_ops(param_grad):
context = dict()
create_op_callbacks = []
for p, g in param_grad:
clip_attr = getattr(p, 'clip_attr', NullGradientClipAttr())
if clip_attr is None:
clip_attr = NullGradientClipAttr()
if not isinstance(clip_attr, BaseGradientClipAttr):
raise TypeError(
"clip attribute should be an instance of BaseGradientClippingAttr"
)
clip_attr.process_context(context=context, p_g=param_grad)
create_op_callbacks.append(
functools.partial(
clip_attr.create_operators, param=p, grad=g))
return [each_callback() for each_callback in create_op_callbacks]
ClipByValue = GradientClipByValue