kmeans.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2020, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

#include "math-precomp.h"  // Precompiled headers

#include <mrpt/math/kmeans.h>

// This file is just a stub for the k-means++ library so MRPT users don't need
//  to include those headers too.

// Include the kmeans++ library, by David Arthur (darthur@gmail.com), 2009:
#include "kmeans++/KMeans.h"

using namespace std;
using namespace mrpt;
using namespace mrpt::math;

namespace mrpt::math::detail
{
/* -------------------------------------------
                 internal_kmeans
   ------------------------------------------- */
template <>
double internal_kmeans<double>(
    [[maybe_unused]] const bool use_kmeansplusplus_method, const size_t nPoints,
    const size_t k, const size_t dims, const double* points,
    const size_t attempts, double* out_center, int* out_assignments)
{
    return RunKMeans(
        nPoints, k, dims, const_cast<double*>(points), attempts, out_center,
        out_assignments);
}

template <>
double internal_kmeans<float>(
    [[maybe_unused]] const bool use_kmeansplusplus_method, const size_t nPoints,
    const size_t k, const size_t dims, const float* points,
    const size_t attempts, float* out_center, int* out_assignments)
{
    std::vector<double> points_d(nPoints * dims);
    std::vector<double> centers_d(k * dims);
    // Convert: float -> double
    for (size_t i = 0; i < nPoints * dims; i++) points_d[i] = double(points[i]);

    const double ret = RunKMeans(
        nPoints, k, dims, &points_d[0], attempts, &centers_d[0],
        out_assignments);

    // Convert: double -> float
    if (out_center)
        for (size_t i = 0; i < k * dims; i++)
            out_center[i] = float(centers_d[i]);

    return ret;
}
}  // namespace mrpt::math::detail