30 lines
1.2 KiB
Python
30 lines
1.2 KiB
Python
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# Adapt from https://github.com/vllm-project/vllm/blob/main/vllm/model_executor/layers/batch_invariant.py
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# SPDX-License-Identifier: Apache-2.0
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# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
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# Copyright (c) 2026 Huawei Technologies Co., Ltd. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# This file is a part of the vllm-ascend project.
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#
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import torch
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def softmax_batch_invariant(input_, dim, dtype=None):
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# Compute softmax in a deterministic way
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# First subtract max for numerical stability (standard practice)
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input_max = torch.amax(input_, dim=dim, keepdim=True)
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input_ = input_ - input_max
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exp_x = torch.exp(input_)
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sum_exp_x = torch.sum(exp_x, dim=dim, keepdim=True)
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return exp_x / sum_exp_x
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