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Paddle/python/paddle/fluid/imperative/layers.py

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3.4 KiB

# 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 contextlib
import sys
import numpy as np
from paddle.fluid import core
from paddle.fluid import framework
from paddle.fluid.imperative import base
__all__ = ['Layer', 'PyLayer']
class Layer(core.Layer):
"""Layers composed of operators."""
def __init__(self, dtype=core.VarDesc.VarType.FP32, name=None):
self._built = False
self._dtype = dtype
def parameters(self):
return []
def clear_gradients(self):
for p in self.parameters():
p._clear_gradient()
def _build_once(self, inputs):
pass
def __call__(self, *inputs):
if not self._built:
self._build_once(*inputs)
outputs = self.forward(*inputs)
self._built = True
return outputs
def forward(self, *inputs):
raise NotImplementedError
def backward(self, *inputs):
raise ValueError("Layer shouldn't implement backward")
class PyLayer(core.PyLayer):
"""Layers composed of user-defined python codes."""
def __init__(self):
super(PyLayer, self).__init__()
@classmethod
def _do_forward(cls, inputs):
return cls._to_tuple(cls.forward(inputs))
@classmethod
def _do_backward(cls, inputs):
return cls._to_tuple(cls.backward(inputs))
@staticmethod
def _to_tuple(inputs):
if not isinstance(inputs, list) and not isinstance(inputs, tuple):
inputs = [inputs]
ret = []
for inp in inputs:
tensor = core.LoDTensor()
tensor.set(inp, core.CPUPlace())
ret.append(tensor)
return tuple(ret)
@staticmethod
def forward(*inputs):
raise NotImplementedError
@staticmethod
def backward(*douts):
raise NotImplementedError
@classmethod
def __call__(cls, *inputs):
tracer = framework._imperative_tracer()
block = framework.default_main_program().current_block()
ivar_inputs = [x._ivar for x in inputs]
if not hasattr(cls, 'forward_id'):
cls.forward_id = core.PyLayer.num_funcs() + 1
PyLayer.register_func(cls.forward_id, cls._do_forward)
cls.backward_id = core.PyLayer.num_funcs() + 1
PyLayer.register_func(cls.backward_id, cls._do_backward)
iop = core.OpBase()
iop.forward_id = cls.forward_id
iop.backward_id = cls.backward_id
block.ops.append(iop)
ivars = tracer.py_trace(iop, ivar_inputs, False)
ret = []
for ivar in ivars:
tensor = ivar.value().get_tensor()
py_var = framework.Variable(
block,
type=core.VarDesc.VarType.LOD_TENSOR,
name=None,
shape=tensor.shape(),
dtype=tensor._dtype(),
ivar=ivar)
ret.append(py_var)
return ret