SO_SE_average.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */

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

#include <mrpt/poses/SO_SE_average.h>

using namespace mrpt;
using namespace mrpt::math;
using namespace mrpt::utils;
using namespace mrpt::poses;

// -----------   SO_average<2> --------------------
SO_average<2>::SO_average()
        : enable_exception_on_undeterminate(false),
          m_count(0),
          m_accum_x(0),
          m_accum_y(0)
{
}
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()
        : enable_exception_on_undeterminate(false), m_count(0), m_accum_rot()
{
        clear();
}
void SO_average<3>::clear()
{
        m_count = .0;
        m_accum_rot.setZero();
}
void SO_average<3>::append(const Eigen::Matrix3d& M) { append(M, 1.0); }
void SO_average<3>::append(const Eigen::Matrix3d& M, const double weight)
{
        m_count += weight;
        m_accum_rot += weight * M;
}
// See: eq. (3.7) in "MEANS AND AVERAGING IN THE GROUP OF ROTATIONS", MAHER
// MOAKHER, 2002.
Eigen::Matrix3d SO_average<3>::get_average() const
{
        ASSERT_ABOVE_(m_count, 0);
        const Eigen::Matrix3d MtM = m_accum_rot.transpose() * m_accum_rot;

        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::utils::sign(m_accum_rot.determinant()) / 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 Eigen::Matrix3d::Identity();
        }

        Eigen::Matrix3d D = Eigen::Matrix3d::Zero();
        D(0, 0) = d1;
        D(1, 1) = d2;
        D(2, 2) = d3;
        Eigen::Matrix3d ret =
                m_accum_rot * svd.matrixU() * D * svd.matrixU().transpose();
        return ret;
}

// -----------   SE_average<2> --------------------
SE_average<2>::SE_average()
        : enable_exception_on_undeterminate(false),
          m_count(0),
          m_accum_x(0),
          m_accum_y(0),
          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>::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()
        : enable_exception_on_undeterminate(false),
          m_count(0),
          m_accum_x(0),
          m_accum_y(0),
          m_accum_z(0),
          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>::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());
}