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paddlepaddle--paddle/paddle/phi/kernels/cpu/erfinv_kernel.cc
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2026-07-13 12:40:42 +08:00

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// 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.
#ifndef _USE_MATH_DEFINES
#define _USE_MATH_DEFINES // use M_2_SQRTPI on Windows
#endif
#include "paddle/phi/kernels/erfinv_kernel.h"
#include <limits>
#include "paddle/phi/core/kernel_registry.h"
#include "paddle/phi/kernels/funcs/eigen/common.h"
namespace phi {
template <typename T, typename Context>
void ErfinvKernel(const Context& dev_ctx,
const DenseTensor& x,
DenseTensor* out) {
dev_ctx.template Alloc<T>(out);
if (out && out->numel() == 0) {
return;
}
auto eigen_in = EigenVector<T>::Flatten(x);
auto eigen_out = EigenVector<T>::Flatten(*out);
auto& place = *dev_ctx.eigen_device();
constexpr T half = static_cast<T>(0.5);
constexpr T half_sqrt = static_cast<T>(M_SQRT1_2);
constexpr T one = static_cast<T>(1);
const T nan_val = std::numeric_limits<T>::quiet_NaN();
// erfinv is only defined on [-1, 1]; align with PyTorch/scipy by returning
// NaN for |x| > 1 (boundary +/-1 still yields +/-inf through ndtri).
eigen_out.device(place) =
(eigen_in.abs() > eigen_in.constant(one))
.select(eigen_in.constant(nan_val),
(eigen_in * half + half).ndtri() * half_sqrt);
}
} // namespace phi
PD_REGISTER_KERNEL(erfinv, CPU, ALL_LAYOUT, phi::ErfinvKernel, float, double) {}