// ----------------------------------------------------------------------------
// -                        Open3D: www.open3d.org                            -
// ----------------------------------------------------------------------------
// Copyright (c) 2018-2023 www.open3d.org
// SPDX-License-Identifier: MIT
// ----------------------------------------------------------------------------
//***************************************************************************************/
//
//    Based on Pointnet2 Library (MIT License):
//    https://github.com/sshaoshuai/Pointnet2.PyTorch
//
//    Copyright (c) 2019 Shaoshuai Shi
//
//    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.
//
//***************************************************************************************/

#pragma once

#include <cmath>

namespace open3d {
namespace ml {
namespace contrib {

#define TOTAL_THREADS 1024
#define THREADS_PER_BLOCK 256
#define DIVUP(m, n) ((m) / (n) + ((m) % (n) > 0))

inline int OptNumThreads(int work_size) {
    const int pow_2 = std::log(static_cast<double>(work_size)) / std::log(2.0);

    return max(min(1 << pow_2, TOTAL_THREADS), 1);
}

inline dim3 OptBlockConfig(int x, int y) {
    const int x_threads = OptNumThreads(x);
    const int y_threads =
            max(min(OptNumThreads(y), TOTAL_THREADS / x_threads), 1);
    dim3 block_config(x_threads, y_threads, 1);
    return block_config;
}

}  // namespace contrib
}  // namespace ml
}  // namespace open3d