chore: import upstream snapshot with attribution

paddle/phi/kernels/cpu/eigh_kernel.cc

@@ -0,0 +1,55 @@
+// 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/eigh_kernel.h"
+
+#include "paddle/phi/common/data_type.h"
+#include "paddle/phi/core/kernel_registry.h"
+#include "paddle/phi/kernels/funcs/complex_functors.h"
+#include "paddle/phi/kernels/funcs/values_vectors_functor.h"
+
+namespace phi {
+
+template <typename T, typename Context>
+void EighKernel(const Context& dev_ctx,
+                const DenseTensor& x,
+                const std::string& uplo,
+                DenseTensor* out_w,
+                DenseTensor* out_v) {
+  if (x.numel() == 0) {
+    auto x_dim = x.dims();
+    auto w_dim = slice_ddim(x_dim, 0, x_dim.size() - 1);
+    out_w->Resize(w_dim);
+    out_v->Resize(x_dim);
+    dev_ctx.template Alloc<T>(out_w);
+    dev_ctx.template Alloc<T>(out_v);
+    return;
+  }
+  bool is_lower = (uplo == "L");
+  funcs::MatrixEighFunctor<Context, T> functor;
+  functor(dev_ctx, x, out_w, out_v, is_lower, true);
+}
+
+}  // namespace phi
+
+PD_REGISTER_KERNEL(eigh,
+                   CPU,
+                   ALL_LAYOUT,
+                   phi::EighKernel,
+                   float,
+                   double,
+                   phi::complex64,
+                   phi::complex128) {
+  kernel->OutputAt(0).SetDataType(phi::dtype::ToReal(kernel_key.dtype()));
+}