# 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,
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import numpy as np
import paddle
[docs]def shuffle_dim(x, axis, perm=None):
"""Permute input tensor along aixs given the permutation or randomly.
Args:
x (Tensor):
The input tensor.
axis (int):
The axis to shuffle.
perm (List[int], ndarray, optional):
The order to reorder the tensor along the ``axis``-th dimension.
It is a permutation of ``[0, d)``, where d is the size of the
``axis``-th dimension of the input tensor. If not provided,
a random permutation is used. Defaults to None.
Returns:
Tensor: The shuffled tensor, which has the same shape as x does.
"""
size = x.shape[axis]
if perm is not None and len(perm) != size:
raise ValueError("length of permutation should equals the input "
"tensor's axis-th dimension's size")
if perm is not None:
perm = np.array(perm)
else:
perm = np.random.permutation(size)
perm = paddle.to_tensor(perm)
out = paddle.gather(x, perm, axis)
return out