Add reduce_merge files for reduce op

paddle/fluid/operators/reduce_ops/reduce_functor_op.h

@@ -0,0 +1,58 @@
+/* Copyright (c) 2021 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. */
+
+#pragma once
+#include <string>
+#include <vector>
+
+#include "paddle/fluid/framework/eigen.h"
+#include "paddle/fluid/framework/tensor.h"
+#include "paddle/fluid/operators/amp/fp16_type_traits.h"
+#include "paddle/fluid/platform/device_context.h"
+#include "paddle/fluid/platform/hostdevice.h"
+#include "paddle/fluid/platform/macros.h"
+
+namespace paddle {
+namespace operators {
+
+template <typename T>
+struct CustomMin {
+  __device__ __forceinline__ T operator()(const T &a, const T &b) const {
+    return (b < a) ? b : a;
+  }
+};
+
+template <typename T>
+struct CustomMax {
+  __device__ __forceinline__ T operator()(const T &a, const T &b) const {
+    return (b > a) ? b : a;
+  }
+};
+
+template <typename T>
+struct CustomSum {
+  __device__ __forceinline__ T operator()(const T &a, const T &b) const {
+    return b + a;
+  }
+};
+
+template <typename T>
+struct CustomMul {
+  __device__ __forceinline__ T operator()(const T &a, const T &b) const {
+    return b * a;
+  }
+};
+
+}  // namespace operators
+}  // namespace paddle