chore: import upstream snapshot with attribution

paddle/phi/kernels/cpu/scatter_kernel.cc

@@ -0,0 +1,73 @@
+// 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/scatter_kernel.h"
+
+#include "paddle/phi/backends/cpu/cpu_context.h"
+#include "paddle/phi/core/kernel_registry.h"
+#include "paddle/phi/core/tensor_utils.h"
+#include "paddle/phi/kernels/funcs/scatter.h"
+
+namespace phi {
+
+template <typename T, typename Context>
+void ScatterKernel(const Context &dev_ctx,
+                   const DenseTensor &x,
+                   const DenseTensor &index,
+                   const DenseTensor &updates,
+                   bool overwrite,
+                   DenseTensor *out) {
+  if (index.numel() == 0) {
+    dev_ctx.template Alloc<T>(out);
+    Copy(dev_ctx, x, dev_ctx.GetPlace(), false, out);
+    return;
+  }
+  if (out && out->numel() == 0) {
+    dev_ctx.template Alloc<T>(out);
+    return;
+  }
+  // In place output: Out = X, Out[Ids] = Updates
+  Copy(dev_ctx, x, dev_ctx.GetPlace(), false, out);
+  // Apply ScatterUpdate: Out[index] = Updates[:]
+  const auto &index_type = index.dtype();
+  bool index_type_match =
+      index_type == DataType::INT32 || index_type == DataType::INT64;
+  PADDLE_ENFORCE_EQ(index_type_match,
+                    true,
+                    common::errors::InvalidArgument(
+                        "Index holds the wrong type, it holds [%s],"
+                        "but desires to be [%s] or [%s].",
+                        index_type,
+                        DataType::INT32,
+                        DataType::INT64));
+  if (overwrite) {
+    if (index_type == DataType::INT32) {
+      funcs::ScatterAssign<T, int32_t>(dev_ctx, updates, index, out);
+    } else {
+      funcs::ScatterAssign<T, int64_t>(dev_ctx, updates, index, out);
+    }
+  } else {
+    if (index_type == DataType::INT32) {
+      funcs::ScatterAssignAdd<T, int32_t>(dev_ctx, updates, index, out);
+    } else {
+      funcs::ScatterAssignAdd<T, int64_t>(dev_ctx, updates, index, out);
+    }
+  }
+}
+
+}  // namespace phi
+
+PD_REGISTER_KERNEL(
+    scatter, CPU, ALL_LAYOUT, phi::ScatterKernel, float, double, int, int64_t) {
+}