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
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+//
+//  SelectGrad.cpp
+//  MNN
+//
+//  Created by MNN on 2019/05/26.
+//  Copyright © 2018, Alibaba Group Holding Limited
+//
+
+#include "SelectGrad.hpp"
+#include "core/Macro.h"
+using namespace std;
+namespace MNN {
+using namespace MNN::Express;
+
+class SelectGrad : public OpGrad {
+public:
+    SelectGrad() {
+        mType = SEMI_LINEAR;
+    }
+    virtual std::vector<Express::VARP> onGrad(Express::EXPRP expr,
+                                              const std::vector<Express::VARP>& backwardOutput) override {
+        auto inputs = expr->inputs();
+        auto type = inputs[1]->getInfo()->type;
+        std::vector<VARP> result(inputs.size(), nullptr);
+        if (type.code != halide_type_float) {
+            return result;
+        }
+        auto outputDiff = backwardOutput[0];
+        // d (select(x, a, b)) = da * (x>0) + db * (x < 0)
+        {
+            auto zero = MNN::Express::_ZerosLike(expr->inputs()[1]);
+            result[1] = MNN::Express::_Select(inputs[0], outputDiff, zero);
+            result[2] = MNN::Express::_Select(inputs[0], zero, outputDiff);
+        }
+        return result;
+    }
+};
+
+static void _create() {
+    static SelectGrad _c;
+    OpGrad::insert(OpType_Select, &_c);
+
+}
+
+REGISTER_GRAD(SelectGrad_cpp, _create);
+};
+