chore: import upstream snapshot with attribution

python/paddle/base/initializer.py

@@ -0,0 +1,118 @@
+#   Copyright (c) 2022 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
+
+from typing import TYPE_CHECKING
+
+import paddle
+
+from .data_feeder import check_type
+
+if TYPE_CHECKING:
+    from paddle.nn.initializer import Initializer
+
+__all__ = []
+
+_global_weight_initializer_ = None
+_global_bias_initializer_ = None
+
+
+def _global_weight_initializer() -> Initializer | None:
+    """
+    Return the global weight initializer, The user doesn't need to use it.
+    """
+    return _global_weight_initializer_
+
+
+def _global_bias_initializer() -> Initializer | None:
+    """
+    Return the global weight initializer, The user doesn't need to use it.
+    """
+    return _global_bias_initializer_
+
+
+def set_global_initializer(
+    weight_init: Initializer | None, bias_init: Initializer | None = None
+) -> None:
+    """
+    This API is used to set up global model parameter initializer in framework.
+
+    After this API is invoked, the global initializer will takes effect in subsequent code.
+
+    The model parameters include ``weight`` and ``bias`` . In the framework, they correspond
+    to ``paddle.ParamAttr`` , which is inherited from ``paddle.Tensor`` , and is a persistable Variable.
+    This API only takes effect for model parameters, not for variables created through apis such as
+    :ref:`api_paddle_static_create_global_var` , :ref:`api_paddle_Tensor_create_tensor`.
+
+    If the initializer is also set up by ``param_attr`` or ``bias_attr`` when creating a network layer,
+    the global initializer setting here will not take effect because it has a lower priority.
+
+    If you want to cancel the global initializer in framework, please set global initializer to ``None`` .
+
+    Args:
+        weight_init (Initializer|None): set the global initializer for ``weight`` of model parameters.
+        bias_init (Initializer|None, optional): set the global initializer for ``bias`` of model parameters.
+            Default: None.
+
+    Returns:
+        None
+
+    Examples:
+        .. code-block:: pycon
+
+            >>> import paddle
+            >>> import paddle.nn as nn
+
+            >>> nn.initializer.set_global_initializer(nn.initializer.Uniform(), nn.initializer.Constant())
+            >>> x_var = paddle.uniform((2, 4, 8, 8), dtype='float32', min=-1.0, max=1.0)
+
+            >>> # The weight of conv1 is initialized by Uniform
+            >>> # The bias of conv1 is initialized by Constant
+            >>> conv1 = nn.Conv2D(4, 6, (3, 3))
+            >>> y_var1 = conv1(x_var)
+
+            >>> # If set param_attr/bias_attr too, global initializer will not take effect
+            >>> # The weight of conv2 is initialized by Xavier
+            >>> # The bias of conv2 is initialized by Normal
+            >>> conv2 = nn.Conv2D(
+            ...     4,
+            ...     6,
+            ...     (3, 3),
+            ...     weight_attr=nn.initializer.XavierUniform(),
+            ...     bias_attr=nn.initializer.Normal(),
+            ... )
+            >>> y_var2 = conv2(x_var)
+
+            >>> # Cancel the global initializer in framework, it will takes effect in subsequent code
+            >>> nn.initializer.set_global_initializer(None)
+    """
+
+    check_type(
+        weight_init,
+        'weight_init',
+        (paddle.nn.initializer.Initializer, type(None)),
+        'set_global_initializer',
+    )
+    global _global_weight_initializer_
+    _global_weight_initializer_ = weight_init
+
+    check_type(
+        bias_init,
+        'bias_init',
+        (paddle.nn.initializer.Initializer, type(None)),
+        'set_global_initializer',
+    )
+    global _global_bias_initializer_
+    _global_bias_initializer_ = bias_init