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

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# 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, pir
from ...base import core, framework, unique_name
from ...base.data_feeder import check_variable_and_dtype
from ...base.framework import (
_current_expected_place,
in_dygraph_mode,
in_pir_mode,
)
from .initializer import Initializer
__all__ = []
class UniformInitializer(Initializer):
"""Implements the random uniform distribution initializer
Args:
low (float, optional): Lower boundary of the uniform distribution. Default is :math:`-1.0`.
high (float, optional): Upper boundary of the uniform distribution. Default is :math:`1.0`.
seed (int, optional): Random seed. Default is 0.
diag_num (int, optional): the number of diagonal elements to initialize.
If set to 0, diagonal initialization will be not performed. Default is 0.
diag_step (int, optional): Step size between two diagonal elements,
which is generally the width of the square matrix. Default is 0.
diag_val (float, optional): the value of the diagonal element to be initialized,
default 1.0. It takes effect only if the diag_num is greater than 0. Default is :math:`1.0`.
"""
def __init__(
self,
low: float = -1.0,
high: float = 1.0,
seed: int = 0,
diag_num: int = 0,
diag_step: int = 0,
diag_val: float = 1.0,
) -> None:
assert low is not None
assert high is not None
assert high >= low
assert seed is not None
assert diag_num is not None
assert diag_step is not None
assert diag_val is not None
if diag_num > 0 or diag_step > 0:
assert diag_num > 0 and diag_step > 0
super().__init__()
self._low = low
self._high = high
self._seed = seed
self._diag_num = diag_num
self._diag_step = diag_step
self._diag_val = diag_val
def forward(
self, var: paddle.Tensor, block: pir.Block | None = None
) -> paddle.Tensor | None:
"""Initialize the input tensor with Uniform distribution.
Args:
var(Tensor): Tensor that needs to be initialized.
block(Block|None, optional): The block in which initialization ops
should be added. Used in static graph only, default None.
Returns:
The initialization op
"""
assert not (
isinstance(var, framework.EagerParamBase) and var.is_dist()
), (
"Currently, uniform initializer not support lazy init for dist param."
)
block = self._check_block(block)
assert isinstance(block, (framework.Block, pir.Block))
if not in_dygraph_mode():
check_variable_and_dtype(
var,
"Out",
["uint16", "float16", "float32", "float64"],
"uniform_random",
)
if self._seed == 0:
self._seed = block.program.random_seed
# to be compatible of fp16 initializers
if var.dtype == core.VarDesc.VarType.FP16:
out_dtype = core.VarDesc.VarType.FP32
out_var = block.create_var(
name=unique_name.generate(
".".join(['uniform_random', var.name, 'tmp'])
),
shape=var.shape,
dtype=out_dtype,
type=core.VarDesc.VarType.DENSE_TENSOR,
persistable=False,
)
else:
out_dtype = var.dtype
out_var = var
if in_dygraph_mode():
out_var = _C_ops.uniform(
var.shape,
out_dtype,
self._low,
self._high,
self._seed,
var.place if var.place._type() else _current_expected_place(),
)
if var.dtype == core.VarDesc.VarType.FP16:
var_tmp = _C_ops.cast(out_var, var.dtype)
var_tmp._share_underline_tensor_to(var)
else:
out_var._share_underline_tensor_to(var)
return None
elif in_pir_mode():
if var.dtype == core.DataType.FLOAT16:
out_dtype = core.DataType.FLOAT32
else:
out_dtype = var.dtype
out_var = _C_ops.uniform(
var.shape,
out_dtype,
self._low,
self._high,
self._seed,
_current_expected_place(),
)
if (
var.dtype == core.DataType.FLOAT16
and out_var.dtype != core.DataType.FLOAT16
):
return _C_ops.cast(out_var, var.dtype)
return out_var
else:
op = block.append_op(
type="uniform_random",
inputs={},
outputs={"Out": out_var},
attrs={
"shape": var.shape,
"dtype": out_dtype,
"min": self._low,
"max": self._high,
"seed": self._seed,
"diag_num": self._diag_num,
"diag_step": self._diag_step,
"diag_val": self._diag_val,
},
stop_gradient=True,
)
if var.dtype == core.VarDesc.VarType.FP16:
block.append_op(
type="cast",
inputs={"X": out_var},
outputs={"Out": var},
attrs={"in_dtype": out_var.dtype, "out_dtype": var.dtype},
)
var.op = op
return op
class Uniform(UniformInitializer):
"""The uniform distribution initializer.
Args:
low (float, optional): Lower boundary of the uniform distribution. Default is :math:`-1.0`.
high (float, optional): Upper boundary of the uniform distribution. Default is :math:`1.0`.
name (str|None, optional): For details, please refer to :ref:`api_guide_Name`. Generally, no setting is required. Default: None.
Returns:
A parameter initialized by uniform distribution.
Examples:
.. code-block:: pycon
>>> import paddle
>>> paddle.seed(1)
>>> data = paddle.ones(shape=[3, 1, 2], dtype='float32')
>>> weight_attr = paddle.framework.ParamAttr(
... name="linear_weight",
... initializer=paddle.nn.initializer.Uniform(low=-0.5, high=0.5),
... )
>>> bias_attr = paddle.framework.ParamAttr(
... name="linear_bias",
... initializer=paddle.nn.initializer.Uniform(low=-0.5, high=0.5),
... )
>>> linear = paddle.nn.Linear(2, 2, weight_attr=weight_attr, bias_attr=bias_attr)
>>> print(linear.weight)
Parameter containing:
Tensor(shape=[2, 2], dtype=float32, place=Place(cpu), stop_gradient=False,
[[-0.48212373, 0.26492310],
[ 0.17605734, -0.45379421]])
>>> print(linear.bias)
Parameter containing:
Tensor(shape=[2], dtype=float32, place=Place(cpu), stop_gradient=False,
[-0.11236754, 0.46462214])
>>> res = linear(data)
>>> print(res)
Tensor(shape=[3, 1, 2], dtype=float32, place=Place(cpu), stop_gradient=False,
[[[-0.41843393, 0.27575102]],
[[-0.41843393, 0.27575102]],
[[-0.41843393, 0.27575102]]])
"""
def __init__(
self, low: float = -1.0, high: float = 1.0, name: str | None = None
) -> None:
assert low is not None, 'low should not be None'
assert high is not None, 'high should not be None'
assert high >= low, 'high should greater or equal than low'
super().__init__(
low=low, high=high, seed=0, diag_num=0, diag_step=0, diag_val=1.0
)