CAtan2LookUpTable.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/CAtan2LookUpTable.h>
#include <cmath>
#include <vector>

using namespace mrpt::math;

CAtan2LookUpTable::CAtan2LookUpTable() noexcept
{
    this->resize(-1.0, 1.0, -1.0, 1.0, 0.5);
}
CAtan2LookUpTable::CAtan2LookUpTable(
    double xmin, double xmax, double ymin, double ymax,
    double resolution) noexcept
{
    this->resize(xmin, xmax, ymin, ymax, resolution);
}

void CAtan2LookUpTable::resize(
    double xmin, double xmax, double ymin, double ymax,
    double resolution) noexcept
{
    const double def = .0;
    if (m_grid.getResolution() == resolution)
        m_grid.resize(xmin, xmax, ymin, ymax, def, .0);
    else
        m_grid.setSize(xmin, xmax, ymin, ymax, resolution, &def);

    const size_t nx = m_grid.getSizeX(), ny = m_grid.getSizeY();

    std::vector<double> idx2x(nx), idx2y(ny);

    for (size_t ix = 0; ix < nx; ix++) idx2x[ix] = m_grid.idx2x(ix);
    for (size_t iy = 0; iy < ny; iy++) idx2y[iy] = m_grid.idx2y(iy);

    for (size_t ix = 0; ix < nx; ix++)
    {
        const double x = idx2x[ix];
        for (size_t iy = 0; iy < ny; iy++)
        {
            const double y = idx2y[iy];
            double* cp = m_grid.cellByIndex(ix, iy);
            if (cp) *cp = ::atan2(y, x);
        }
    }
}

CAtan2LookUpTableMultiRes::CAtan2LookUpTableMultiRes(
    const std::map<double, double>& lst_resolutions2extensions) noexcept
{
    resize(lst_resolutions2extensions);
}
void CAtan2LookUpTableMultiRes::resize(
    const std::map<double, double>& lst_resolutions2extensions) noexcept
{
    m_grids.clear();

    for (const auto& it : lst_resolutions2extensions)
    {
        const double res = it.first;
        const double exten = it.second;

        mrpt::containers::CDynamicGrid<double>& dg = m_grids[exten] =
            mrpt::containers::CDynamicGrid<double>(
                -exten, exten, -exten, exten, res);

        const size_t nx = dg.getSizeX(), ny = dg.getSizeY();
        std::vector<double> idx2x(nx), idx2y(ny);

        for (size_t ix = 0; ix < nx; ix++) idx2x[ix] = dg.idx2x(ix);
        for (size_t iy = 0; iy < ny; iy++) idx2y[iy] = dg.idx2y(iy);

        for (size_t ix = 0; ix < nx; ix++)
        {
            const double x = idx2x[ix];
            for (size_t iy = 0; iy < ny; iy++)
            {
                const double y = idx2y[iy];
                double* cp = dg.cellByIndex(ix, iy);
                if (cp) *cp = ::atan2(y, x);
            }
        }
    }
}

bool CAtan2LookUpTableMultiRes::atan2(
    double y, double x, double& out_atan2) const noexcept
{
    for (const auto& it : m_grids)
    {
        const double exten = it.first;
        const mrpt::containers::CDynamicGrid<double>& dg = it.second;

        if (std::abs(x) > exten || std::abs(y) > exten) continue;

        const double* cp = dg.cellByPos(x, y);
        if (!cp) continue;
        out_atan2 = *cp;
        return true;
    }
    return false;
}