src/core/CL/kernels/CLFFTRadixStageKernel.cpp

/*
 * Copyright (c) 2019 ARM Limited.
 *
 * SPDX-License-Identifier: MIT
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#include "arm_compute/core/CL/kernels/CLFFTRadixStageKernel.h"

#include "arm_compute/core/CL/CLHelpers.h"
#include "arm_compute/core/CL/CLKernelLibrary.h"
#include "arm_compute/core/CL/CLValidate.h"
#include "arm_compute/core/CL/ICLTensor.h"
#include "arm_compute/core/TensorInfo.h"
#include "arm_compute/core/Types.h"
#include "arm_compute/core/Utils.h"
#include "arm_compute/core/Window.h"

#include <cmath>

namespace arm_compute
{
namespace
{
Status validate_arguments(const ITensorInfo *input, const ITensorInfo *output, const FFTRadixStageKernelInfo &config)
{
    ARM_COMPUTE_RETURN_ERROR_ON_F16_UNSUPPORTED(input);
    ARM_COMPUTE_RETURN_ERROR_ON_DATA_TYPE_CHANNEL_NOT_IN(input, 2, DataType::F32);
    ARM_COMPUTE_RETURN_ERROR_ON(CLFFTRadixStageKernel::supported_radix().count(config.radix) == 0);
    ARM_COMPUTE_RETURN_ERROR_ON(std::set<unsigned int>({ 0, 1 }).count(config.axis) == 0);
    ARM_COMPUTE_RETURN_ERROR_ON(input->tensor_shape()[config.axis] % config.radix);

    // Checks performed when output is configured
    if((output != nullptr) && (output->total_size() != 0))
    {
        ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_SHAPES(input, output);
        ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_DATA_TYPES(input, output);
    }

    return Status{};
}

std::pair<Status, Window> validate_and_configure_window(ITensorInfo *input, ITensorInfo *output, const FFTRadixStageKernelInfo &config)
{
    if(output != nullptr)
    {
        auto_init_if_empty(*output, *input);
    }

    // Setup window steps
    Steps steps;
    steps.set(config.axis, config.radix);

    Window win = calculate_max_window(*input, steps);
    if(output != nullptr)
    {
        output->set_valid_region(ValidRegion(Coordinates(), output->tensor_shape()));
    }

    return std::make_pair(Status{}, win);
}
} // namespace

CLFFTRadixStageKernel::CLFFTRadixStageKernel()
    : _input(nullptr), _output(nullptr), _run_in_place(false)
{
}

void CLFFTRadixStageKernel::configure(ICLTensor *input, ICLTensor *output, const FFTRadixStageKernelInfo &config)
{
    ARM_COMPUTE_ERROR_ON_NULLPTR(input);
    ARM_COMPUTE_ERROR_THROW_ON(validate_arguments(input->info(), (output != nullptr) ? output->info() : nullptr, config));

    _input        = input;
    _output       = output;
    _run_in_place = (output == nullptr) || (output == input);

    // Create build options
    CLBuildOptions build_opts;
    build_opts.add_option_if(_run_in_place, "-DIN_PLACE");

    // Create kernel
    std::string kernel_name = "fft";
    kernel_name += "_radix_" + support::cpp11::to_string(config.radix);
    kernel_name += (config.is_first_stage) ? "_first_stage" : "";
    kernel_name += "_axis_" + support::cpp11::to_string(config.axis);
    _kernel = static_cast<cl::Kernel>(CLKernelLibrary::get().create_kernel(kernel_name, build_opts.options()));

    // Set static arguments if not the first stage
    if(!config.is_first_stage)
    {
        const unsigned int Ni        = config.Nx * config.radix;
        const float        exp_const = (-2.0 * M_PI) / static_cast<float>(Ni);
        unsigned int       idx       = (1 + (_run_in_place ? 0 : 1)) * num_arguments_per_3D_tensor(); // Skip the input and output parameters
        _kernel.setArg<cl_uint>(idx++, config.Nx);
        _kernel.setArg<cl_uint>(idx++, Ni);
        _kernel.setArg<cl_float>(idx, exp_const);
    }

    // Configure kernel window
    auto win_config = validate_and_configure_window(input->info(), (_run_in_place) ? nullptr : output->info(), config);
    ARM_COMPUTE_ERROR_THROW_ON(win_config.first);
    ICLKernel::configure_internal(win_config.second);

    // Set config_id for enabling LWS tuning
    _config_id = kernel_name;
    _config_id += "_";
    _config_id += lower_string(string_from_data_type(input->info()->data_type()));
    _config_id += "_";
    _config_id += support::cpp11::to_string(input->info()->dimension(0));
    _config_id += "_";
    _config_id += support::cpp11::to_string(input->info()->dimension(1));
}

Status CLFFTRadixStageKernel::validate(const ITensorInfo *input, const ITensorInfo *output, const FFTRadixStageKernelInfo &config)
{
    const bool run_in_place = (output == nullptr) || (output == input);
    ARM_COMPUTE_RETURN_ON_ERROR(validate_arguments(input, output, config));
    ARM_COMPUTE_RETURN_ON_ERROR(validate_and_configure_window(input->clone().get(),
                                                              (run_in_place) ? nullptr : output->clone().get(),
                                                              config)
                                .first);

    return Status{};
}

std::set<unsigned int> CLFFTRadixStageKernel::supported_radix()
{
    return std::set<unsigned int> { 2, 3, 4, 5, 7, 8 };
}

void CLFFTRadixStageKernel::run(const Window &window, cl::CommandQueue &queue)
{
    ARM_COMPUTE_ERROR_ON_UNCONFIGURED_KERNEL(this);
    ARM_COMPUTE_ERROR_ON_INVALID_SUBWINDOW(ICLKernel::window(), window);

    Window collapsed = window.collapse_if_possible(ICLKernel::window(), Window::DimZ);
    Window slice     = collapsed.first_slice_window_3D();

    do
    {
        unsigned int idx = 0;
        add_3D_tensor_argument(idx, _input, slice);
        if(!_run_in_place)
        {
            add_3D_tensor_argument(idx, _output, slice);
        }
        enqueue(queue, *this, slice, lws_hint());
    }
    while(collapsed.slide_window_slice_3D(slice));
}
} // namespace arm_compute