SO_SE_average.cpp

Go to the documentation of this file.

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2019, 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 "poses-precomp.h"  // Precompiled headers

#include <mrpt/math/TPose2D.h>
#include <mrpt/math/TPose3D.h>
#include <mrpt/poses/SO_SE_average.h>
#include <Eigen/Dense>

using namespace mrpt;
using namespace mrpt::math;

using namespace mrpt::poses;

// -----------   SO_average<2> --------------------
SO_average<2>::SO_average() = default;

void SO_average<2>::clear()
{
    m_count = .0;
    m_accum_x = m_accum_y = .0;
}
void SO_average<2>::append(const double orientation_rad)
{
    append(orientation_rad, 1.0);
}
void SO_average<2>::append(const double orientation_rad, const double weight)
{
    m_count += weight;
    m_accum_x += cos(orientation_rad) * weight;
    m_accum_y += sin(orientation_rad) * weight;
}
double SO_average<2>::get_average() const
{
    ASSERT_ABOVE_(m_count, 0);
    const double x = m_accum_x / m_count;
    const double y = m_accum_y / m_count;
    errno = 0;
    double ang = atan2(y, x);
    if (errno == EDOM)
    {
        if (enable_exception_on_undeterminate)
            throw std::runtime_error(
                "[SO_average<2>::get_average()] Undetermined average value");
        else
            ang = 0;
    }
    return ang;
}

// -----------   SO_average<3> --------------------
SO_average<3>::SO_average() : m_accum_rot() { clear(); }
void SO_average<3>::clear()
{
    m_count = .0;
    m_accum_rot.setZero();
}
void SO_average<3>::append(const mrpt::math::CMatrixDouble33& M)
{
    append(M, 1.0);
}
void SO_average<3>::append(
    const mrpt::math::CMatrixDouble33& M, const double weight)
{
    m_count += weight;
    m_accum_rot.asEigen() += weight * M.asEigen();
}
// See: eq. (3.7) in "MEANS AND AVERAGING IN THE GROUP OF ROTATIONS", MAHER
// MOAKHER, 2002.
mrpt::math::CMatrixDouble33 SO_average<3>::get_average() const
{
    ASSERT_ABOVE_(m_count, 0);
    const Eigen::Matrix3d MtM = m_accum_rot.transpose() * m_accum_rot.asEigen();

    Eigen::JacobiSVD<Eigen::Matrix3d> svd(MtM, Eigen::ComputeFullU);
    const Eigen::Vector3d vs = svd.singularValues();

    errno = 0;
    const double d1 = 1.0 / sqrt(vs[0]);
    const double d2 = 1.0 / sqrt(vs[1]);
    const double d3 = mrpt::sign(m_accum_rot.det()) / sqrt(vs[2]);
    if (errno != 0)
    {
        if (enable_exception_on_undeterminate)
            throw std::runtime_error(
                "[SO_average<3>::get_average()] Undetermined average value");
        else
            return mrpt::math::CMatrixDouble33::Identity();
    }

    mrpt::math::CMatrixDouble33 D = mrpt::math::CMatrixDouble33::Zero();
    D(0, 0) = d1;
    D(1, 1) = d2;
    D(2, 2) = d3;
    return mrpt::math::CMatrixDouble33(
        m_accum_rot.asEigen() * svd.matrixU() * D.asEigen() *
        svd.matrixU().transpose());
}

// -----------   SE_average<2> --------------------
SE_average<2>::SE_average() : m_rot_part() { clear(); }
void SE_average<2>::clear()
{
    m_count = .0;
    m_accum_x = m_accum_y = .0;
    m_rot_part.clear();
}
void SE_average<2>::append(const mrpt::poses::CPose2D& p) { append(p, 1.0); }
void SE_average<2>::append(const mrpt::poses::CPose2D& p, const double weight)
{
    m_count += weight;
    m_accum_x += weight * p.x();
    m_accum_y += weight * p.y();
    m_rot_part.append(p.phi(), weight);
}
void SE_average<2>::append(const mrpt::math::TPose2D& p, const double weight)
{
    m_count += weight;
    m_accum_x += weight * p.x;
    m_accum_y += weight * p.y;
    m_rot_part.append(p.phi, weight);
}
void SE_average<2>::get_average(mrpt::poses::CPose2D& ret_mean) const
{
    ASSERT_ABOVE_(m_count, 0);
    ret_mean.x(m_accum_x / m_count);
    ret_mean.y(m_accum_y / m_count);
    const_cast<SO_average<2>*>(&m_rot_part)->enable_exception_on_undeterminate =
        this->enable_exception_on_undeterminate;
    ret_mean.phi(m_rot_part.get_average());
}

// -----------   SE_average<3> --------------------
SE_average<3>::SE_average() : m_rot_part() { clear(); }
void SE_average<3>::clear()
{
    m_count = .0;
    m_accum_x = m_accum_y = m_accum_z = .0;
    m_rot_part.clear();
}
void SE_average<3>::append(const mrpt::poses::CPose3D& p) { append(p, 1.0); }
void SE_average<3>::append(const mrpt::poses::CPose3D& p, const double weight)
{
    m_count += weight;
    m_accum_x += weight * p.x();
    m_accum_y += weight * p.y();
    m_accum_z += weight * p.z();
    m_rot_part.append(p.getRotationMatrix(), weight);
}
void SE_average<3>::append(const mrpt::math::TPose3D& p, const double weight)
{
    append(CPose3D(p), weight);
}
void SE_average<3>::get_average(mrpt::poses::CPose3D& ret_mean) const
{
    ASSERT_ABOVE_(m_count, 0);
    ret_mean.x(m_accum_x / m_count);
    ret_mean.y(m_accum_y / m_count);
    ret_mean.z(m_accum_z / m_count);
    const_cast<SO_average<3>*>(&m_rot_part)->enable_exception_on_undeterminate =
        this->enable_exception_on_undeterminate;
    ret_mean.setRotationMatrix(m_rot_part.get_average());
}