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paddlepaddle--paddle/paddle/phi/kernels/impl/gumbel_softmax_kernel_impl.h
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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.
#pragma once
#include <iostream>
#include <random>
#include "paddle/phi/core/dense_tensor.h"
#include "paddle/phi/kernels/funcs/axis_utils.h"
#include "paddle/phi/kernels/funcs/eigen/common.h"
#include "paddle/phi/kernels/funcs/math_function.h"
#include "paddle/phi/kernels/funcs/softmax.h"
#include "paddle/phi/kernels/funcs/softmax_impl.h"
namespace phi {
template <typename Context, typename T, int64_t Rank>
struct ArgMaxFunctor {
void operator()(const Context& dev_ctx UNUSED,
const DenseTensor& in,
DenseTensor* index_tensor,
const int64_t& axis) {
auto in_eigen = EigenTensor<T, Rank>::From(in, in.dims());
auto index_eigen = EigenTensor<int, Rank - 1>::From(*index_tensor);
index_eigen = in_eigen.argmax(axis).template cast<int>();
}
};
template <typename Context, typename T>
struct GumbleNoiseGenerator;
template <typename Context, typename T>
struct OneHotGenerator;
template <typename T, typename Context>
void GumbelSoftmaxKernelHelper(const Context& dev_ctx,
const DenseTensor& x,
float temperature,
bool hard,
int axis,
DenseTensor* out) {
const int rank = x.dims().size();
axis = funcs::CanonicalAxis(axis, rank);
int64_t axis_dim = x.dims()[axis];
PADDLE_ENFORCE_GT(temperature,
0,
common::errors::InvalidArgument(
"The temperature must be greater than 0. But "
"received temperature = %f",
temperature));
// allocate memory on device.
dev_ctx.template Alloc<T>(out);
if (out->numel() == 0) {
return;
}
// For 0D Tensor
if (rank == 0) {
funcs::set_constant(dev_ctx, out, static_cast<T>(1.0));
return;
}
// TODO(large-tensor): SoftmaxFunctor not support int64
PADDLE_ENFORCE_LE_INT_MAX(axis_dim, "axis_dim");
const int size_to_axis = funcs::SizeToAxis(axis, x.dims());
const int size_from_axis = funcs::SizeFromAxis(axis, x.dims());
DenseTensor x_noise_2d, out_2d(*out);
x_noise_2d.Resize({size_to_axis, size_from_axis});
out_2d.Resize({size_to_axis, size_from_axis});
// generate gumbel noise and add it to X
auto* x_noise_data = dev_ctx.template Alloc<T>(&x_noise_2d);
GumbleNoiseGenerator<Context, T>::Transform(dev_ctx,
x.data<T>(),
x_noise_data,
size_to_axis,
size_from_axis,
temperature);
funcs::SoftmaxFunctor<Context, T>()(dev_ctx, axis_dim, &x_noise_2d, &out_2d);
if (hard) {
OneHotGenerator<Context, T>::Transform(dev_ctx, x, out, axis);
}
}
template <typename T, typename Context>
void GumbelSoftmaxKernel(const Context& dev_ctx,
const DenseTensor& x,
float temperature,
bool hard,
int axis,
DenseTensor* out) {
GumbelSoftmaxKernelHelper<T, Context>(
dev_ctx, x, temperature, hard, axis, out);
}
} // namespace phi