chore: import upstream snapshot with attribution

2026-07-13 13:33:03 +08:00
commit 5b57521aa1
8226 changed files with 3425766 additions and 0 deletions
@@ -0,0 +1,49 @@
+//
+//  SeluGrad.cpp
+//  MNN
+//
+//  Created by MNN on 2022/08/09.
+//  Copyright © 2018, Alibaba Group Holding Limited
+//
+
+#include "OpGrad.hpp"
+#include "core/Macro.h"
+using namespace std;
+namespace MNN {
+using namespace MNN::Express;
+
+class SeluGrad : public OpGrad {
+public:
+    virtual std::vector<Express::VARP> onGrad(Express::EXPRP expr,
+                                              const std::vector<Express::VARP>& backwardOutput) override {
+        std::vector<Express::VARP> res{nullptr};
+        auto input = expr->inputs()[0];
+        std::unique_ptr<OpT> forwardOp(expr->get()->UnPack());
+        auto param = forwardOp->main.AsSelu();
+        float scale = param->scale;
+        float alpha = param->alpha;
+
+        // selu(x) = scale * alpha * (exp(x) - 1), if x <= 0
+        //           scale * x, if x > 0
+
+        // d selu(x) = scale * alpha * exp(x), if x <= 0
+        //             scale, if x > 0
+
+        auto mask0 = _Cast<float>(_Greater(input, _Scalar(0.0f)));
+        auto mask1 = _Cast<float>(_LessEqual(input, _Scalar(0.0f)));
+        auto factor = mask0 * _Scalar<float>(scale) + mask1 * _Scalar<float>(scale * alpha) * _Exp(input);
+
+        res[0] = factor * backwardOutput[0];
+        return res;
+    }
+};
+
+static void _create() {
+    static SeluGrad _c;
+    OpGrad::insert(OpType_Selu, &_c);
+
+}
+
+REGISTER_GRAD(SeluGrad_cpp, _create);
+};
+