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paddlepaddle--paddle/python/paddle/nn/initializer/constant.py
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2026-07-13 12:40:42 +08:00

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Python

# 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.
from __future__ import annotations
import paddle
from paddle import _C_ops
from ...base import core, framework
from ...base.framework import (
_current_expected_place,
in_dygraph_mode,
in_dynamic_or_pir_mode,
)
# TODO: define the initializers of Constant in neural network
from .initializer import Initializer
__all__ = []
class ConstantInitializer(Initializer):
"""Implements the constant initializer
Args:
value (float32, optional): constant value to initialize the variable. Default: 0.0.
"""
def __init__(self, value: float = 0.0, force_cpu: bool = False) -> None:
assert value is not None
super().__init__()
self._value = value
self._force_cpu = force_cpu
def forward(
self,
var: paddle.Tensor,
block: paddle.pir.Block | None = None,
) -> paddle.Tensor | None:
"""Initialize the input tensor with constant.
Args:
var(Tensor): Tensor that needs to be initialized.
block(Block, optional): The block in which initialization ops
should be added. Used in static graph only, default None.
Returns:
The initialization op
"""
block = self._check_block(block)
assert isinstance(
var,
(
framework.Variable,
framework.EagerParamBase,
paddle.pir.Value,
paddle.pir.core.ParameterMeta,
),
)
assert isinstance(block, (framework.Block, paddle.pir.Block))
if in_dynamic_or_pir_mode():
place = _current_expected_place()
if self._force_cpu:
place = core.CPUPlace()
if in_dygraph_mode():
if isinstance(var, framework.EagerParamBase) and var.is_dist():
out_var = _C_ops.full(
var._local_shape, float(self._value), var.dtype, place
)
out_var = (
paddle.distributed.auto_parallel.api.dtensor_from_local(
out_var, var.process_mesh, var.placements
)
)
out_var._share_underline_tensor_to(var)
else:
_C_ops.full_(
var, var.shape, float(self._value), var.dtype, place
)
return None
else:
return _C_ops.full(
var.shape, float(self._value), var.dtype, place
)
else:
op = block.append_op(
type="fill_constant",
outputs={"Out": var},
attrs={
"shape": var.shape,
"dtype": int(var.dtype),
"value": float(self._value),
'str_value': str(float(self._value)),
'force_cpu': self._force_cpu,
},
stop_gradient=True,
)
var.op = op
return op
class Constant(ConstantInitializer):
"""Implement the constant initializer.
Args:
value (float32|float64, optional): constant value to initialize the parameter. Default: 0.0.
Examples:
.. code-block:: pycon
>>> import paddle
>>> import paddle.nn as nn
>>> paddle.seed(2023)
>>> data = paddle.rand([30, 10, 2], dtype='float32')
>>> linear = nn.Linear(2, 4, weight_attr=nn.initializer.Constant(value=2.0))
>>> res = linear(data)
>>> print(linear.weight)
Parameter containing:
Tensor(shape=[2, 4], dtype=float32, place=Place(cpu), stop_gradient=False,
[[2., 2., 2., 2.],
[2., 2., 2., 2.]])
"""
def __init__(self, value: float = 0.0) -> None:
if value is None:
raise ValueError("value must not be none.")
super().__init__(value=value, force_cpu=False)