wehub-resource-sync
50 lines
1.3 KiB
C++
50 lines
1.3 KiB
C++
//
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// SeluGrad.cpp
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// MNN
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//
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// Created by MNN on 2022/08/09.
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// Copyright © 2018, Alibaba Group Holding Limited
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//
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#include "OpGrad.hpp"
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#include "core/Macro.h"
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using namespace std;
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namespace MNN {
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using namespace MNN::Express;
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class SeluGrad : public OpGrad {
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public:
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virtual std::vector<Express::VARP> onGrad(Express::EXPRP expr,
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const std::vector<Express::VARP>& backwardOutput) override {
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std::vector<Express::VARP> res{nullptr};
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auto input = expr->inputs()[0];
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std::unique_ptr<OpT> forwardOp(expr->get()->UnPack());
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auto param = forwardOp->main.AsSelu();
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float scale = param->scale;
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float alpha = param->alpha;
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// selu(x) = scale * alpha * (exp(x) - 1), if x <= 0
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// scale * x, if x > 0
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// d selu(x) = scale * alpha * exp(x), if x <= 0
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// scale, if x > 0
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auto mask0 = _Cast<float>(_Greater(input, _Scalar(0.0f)));
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auto mask1 = _Cast<float>(_LessEqual(input, _Scalar(0.0f)));
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auto factor = mask0 * _Scalar<float>(scale) + mask1 * _Scalar<float>(scale * alpha) * _Exp(input);
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res[0] = factor * backwardOutput[0];
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return res;
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}
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};
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static void _create() {
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static SeluGrad _c;
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OpGrad::insert(OpType_Selu, &_c);
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}
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REGISTER_GRAD(SeluGrad_cpp, _create);
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};
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