chore: import upstream snapshot with attribution

paddle/phi/kernels/cpu/prelu_kernel.cc

@@ -0,0 +1,74 @@
+// Copyright (c) 2022 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,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "paddle/phi/kernels/prelu_kernel.h"
+
+#include "paddle/phi/backends/cpu/cpu_context.h"
+#include "paddle/phi/core/kernel_registry.h"
+
+namespace phi {
+
+template <typename T, typename Context>
+void PReluKernel(const Context& dev_ctx,
+                 const DenseTensor& x,
+                 const DenseTensor& alpha,
+                 const std::string& data_format,
+                 const std::string& mode,
+                 DenseTensor* out) {
+  const T* x_ptr = x.data<T>();
+  const T* alpha_ptr = alpha.data<T>();
+  T* o_ptr = dev_ctx.template Alloc<T>(out);
+  if (out && out->numel() == 0) {
+    return;
+  }
+
+  int numel = static_cast<int>(x.numel());
+  auto dim = x.dims();
+  int index = 0;
+  int i = 0;
+  if (mode == "channel") {
+    if (data_format == "NCHW") {
+      int temp = 1;
+      for (int j = 2; j < dim.size(); j++) {
+        temp *= static_cast<int>(dim[j]);
+      }
+      for (i = 0; i < numel; i++) {
+        index = static_cast<int>((i / temp) % dim[1]);
+        o_ptr[i] = x_ptr[i] > 0 ? x_ptr[i] : alpha_ptr[index] * x_ptr[i];
+      }
+    } else {
+      for (i = 0; i < numel; i++) {
+        index = static_cast<int>(i % dim[dim.size() - 1]);
+        o_ptr[i] = x_ptr[i] > 0 ? x_ptr[i] : alpha_ptr[index] * x_ptr[i];
+      }
+    }
+  } else if (mode == "element") {
+    int temp = 1;
+    for (int j = 1; j < dim.size(); j++) {
+      temp *= static_cast<int>(dim[j]);
+    }
+    for (i = 0; i < numel; i++) {
+      index = i % temp;
+      o_ptr[i] = x_ptr[i] > 0 ? x_ptr[i] : alpha_ptr[index] * x_ptr[i];
+    }
+  } else {
+    for (i = 0; i < numel; i++) {
+      o_ptr[i] = x_ptr[i] > 0 ? x_ptr[i] : alpha_ptr[0] * x_ptr[i];
+    }
+  }
+}
+
+}  // namespace phi
+
+PD_REGISTER_KERNEL(prelu, CPU, ALL_LAYOUT, phi::PReluKernel, float, double) {}