chore: import upstream snapshot with attribution

paddle/phi/kernels/impl/eye_kernel_impl.h

@@ -0,0 +1,56 @@
+// 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.
+
+#pragma once
+
+#include "paddle/phi/common/scalar.h"
+#include "paddle/phi/kernels/funcs/for_range.h"
+#include "paddle/phi/kernels/funcs/math_function.h"
+
+namespace phi {
+
+template <typename T>
+struct EyeFunctor {
+  EyeFunctor(int64_t num_columns, T* output)
+      : num_columns_(num_columns), output_(output) {}
+
+  HOSTDEVICE void operator()(size_t idx) const {
+    output_[idx * num_columns_ + idx] = static_cast<T>(1);
+  }
+
+  int64_t num_columns_;
+  T* output_;
+};
+
+template <typename T, typename Context>
+void EyeKernel(const Context& dev_ctx,
+               const Scalar& num_rows,
+               const Scalar& num_columns,
+               DataType dtype UNUSED,
+               DenseTensor* out) {
+  auto columns = num_columns.to<int64_t>();
+  auto rows = num_rows.to<int64_t>();
+  if (columns == -1) {
+    columns = rows;
+  }
+  T* out_data = dev_ctx.template Alloc<T>(out);
+  funcs::SetConstant<Context, T> set_zero;
+  set_zero(dev_ctx, out, static_cast<T>(0));
+  int64_t num_eyes = (std::min)(rows, columns);
+  funcs::ForRange<Context> for_range(dev_ctx, num_eyes);
+  EyeFunctor<T> functor(columns, out_data);
+  for_range(functor);
+}
+
+}  // namespace phi