chore: import upstream snapshot with attribution

paddle/phi/kernels/gpu/lgamma_kernel.cu

@@ -0,0 +1,54 @@
+// 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/lgamma_kernel.h"
+
+#include "paddle/phi/backends/gpu/gpu_context.h"
+#include "paddle/phi/common/amp_type_traits.h"
+#include "paddle/phi/core/kernel_registry.h"
+#include "paddle/phi/kernels/funcs/elementwise_base.h"
+
+namespace phi {
+template <typename T>
+struct CudaLgammaFunctor {
+  __device__ __forceinline__ T operator()(const T x) const {
+    using MT = typename MPTypeTrait<T>::Type;
+    const MT mp_x = static_cast<MT>(x);
+    return static_cast<T>(Eigen::numext::lgamma(mp_x));
+  }
+};
+template <typename T, typename Context>
+void LgammaKernel(const Context& dev_ctx,
+                  const DenseTensor& x,
+                  DenseTensor* out) {
+  // XKTODO( add gpu kernel implementation. )
+  dev_ctx.template Alloc<T>(out);
+  if (out && out->numel() == 0) {
+    return;
+  }
+  std::vector<const DenseTensor*> ins = {&x};
+  std::vector<DenseTensor*> outs = {out};
+  auto functor = CudaLgammaFunctor<T>();
+  funcs::ElementwiseKernel<T>(dev_ctx, ins, &outs, functor);
+}
+}  // namespace phi
+
+PD_REGISTER_KERNEL(lgamma,
+                   GPU,
+                   ALL_LAYOUT,
+                   phi::LgammaKernel,
+                   float,
+                   double,
+                   phi::float16,
+                   phi::bfloat16) {}