CPose3DQuatPDFGaussian.h

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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          |
   +------------------------------------------------------------------------+ */
#pragma once

#include <mrpt/math/CMatrixD.h>
#include <mrpt/poses/CPose3DPDF.h>
#include <mrpt/poses/CPose3DQuatPDF.h>
#include <mrpt/poses/CPosePDF.h>

namespace mrpt
{
namespace poses
{
class CPosePDFGaussian;
class CPose3DPDFGaussian;

/** Declares a class that represents a Probability Density function (PDF) of a
 * 3D pose using a quaternion \f$ p(\mathbf{x}) = [x ~ y ~ z ~ qr ~ qx ~ qy ~
 * qz]^\top \f$.
 *
 *   This class implements that PDF using a mono-modal Gaussian distribution.
 * See mrpt::poses::CPose3DQuatPDF for more details, or
 *    mrpt::poses::CPose3DPDF for classes based on Euler angles instead.
 *
 *  Uncertainty of pose composition operations (\f$ y = x \oplus u \f$) is
 * implemented in the methods "CPose3DQuatPDFGaussian::operator+=" and
 * "CPose3DQuatPDF::jacobiansPoseComposition".
 *
 *  For further details on implemented methods and the theory behind them,
 *  see <a
 * href="http://www.mrpt.org/6D_poses:equivalences_compositions_and_uncertainty"
 * >this report</a>.
 *
 * \sa CPose3DQuat, CPose3DQuatPDF, CPose3DPDF, CPose3DQuatPDFGaussianInf
 * \ingroup poses_pdf_grp
 */
class CPose3DQuatPDFGaussian : public CPose3DQuatPDF
{
    DEFINE_SERIALIZABLE(CPose3DQuatPDFGaussian, mrpt::poses)

   protected:
    /** Assures the symmetry of the covariance matrix (eventually certain
     * operations in the math-coprocessor lead to non-symmetric matrixes!)
     */
    void enforceCovSymmetry();

   public:
    /** Default constructor - set all values to zero. */
    CPose3DQuatPDFGaussian();

    /** Constructor which left all the member uninitialized, for using when
     * speed is critical - as argument, use UNINITIALIZED_QUATERNION. */
    CPose3DQuatPDFGaussian(
        mrpt::math::TConstructorFlags_Quaternions constructor_dummy_param);

    /** Constructor from a default mean value, covariance equals to zero. */
    explicit CPose3DQuatPDFGaussian(const CPose3DQuat& init_Mean);

    /** Constructor with mean and covariance. */
    CPose3DQuatPDFGaussian(
        const CPose3DQuat& init_Mean,
        const mrpt::math::CMatrixDouble77& init_Cov);

    /** Constructor from a Gaussian 2D pose PDF (sets to 0 the missing
     * variables). */
    explicit CPose3DQuatPDFGaussian(const CPosePDFGaussian& o);

    /** Constructor from an equivalent Gaussian in Euler angles representation.
     */
    explicit CPose3DQuatPDFGaussian(const CPose3DPDFGaussian& o);

    /** The mean value */
    CPose3DQuat mean;
    /** The 7x7 covariance matrix */
    mrpt::math::CMatrixDouble77 cov;

    inline const CPose3DQuat& getPoseMean() const { return mean; }
    inline CPose3DQuat& getPoseMean() { return mean; }

    void getMean(CPose3DQuat& mean_pose) const override;

    std::tuple<cov_mat_t, type_value> getCovarianceAndMean() const override
    {
        return {cov, mean};
    }

    /** Copy operator, translating if necesary (for example, between particles
     * and gaussian representations) */
    void copyFrom(const CPose3DQuatPDF& o) override;
    /** Copy operator, translating if necesary (for example, between particles
     * and gaussian representations) */
    void copyFrom(const CPosePDF& o);
    /** Copy operator, translating if necesary (for example, between particles
     * and gaussian representations) */
    void copyFrom(const CPose3DPDFGaussian& o);
    /** Save the PDF to a text file, containing the 3D pose in the first line (x
     * y z qr qx qy qz), then the covariance matrix in the next 7 lines. */
    bool saveToTextFile(const std::string& file) const override;

    /** this = p (+) this. This can be used to convert a PDF from local
     * coordinates to global, providing the point (newReferenceBase) from which
     *   "to project" the current pdf. Result PDF substituted the currently
     * stored one in the object. */
    void changeCoordinatesReference(const CPose3DQuat& newReferenceBase);

    /** this = p (+) this. This can be used to convert a PDF from local
     * coordinates to global, providing the point (newReferenceBase) from which
     *   "to project" the current pdf. Result PDF substituted the currently
     * stored one in the object.
     */
    void changeCoordinatesReference(const CPose3D& newReferenceBase) override;

    /** Draws a single sample from the distribution */
    void drawSingleSample(CPose3DQuat& outPart) const override;
    /** Draws a number of samples from the distribution, and saves as a list of
     * 1x7 vectors, where each row contains a (x,y,z,qr,qx,qy,qz) datum. */
    void drawManySamples(
        size_t N,
        std::vector<mrpt::math::CVectorDouble>& outSamples) const override;
    /** Returns a new PDF such as: NEW_PDF = (0,0,0) - THIS_PDF */
    void inverse(CPose3DQuatPDF& o) const override;

    /** Unary - operator, returns the PDF of the inverse pose.  */
    inline CPose3DQuatPDFGaussian operator-() const
    {
        CPose3DQuatPDFGaussian p(mrpt::math::UNINITIALIZED_QUATERNION);
        this->inverse(p);
        return p;
    }

    /** Makes: thisPDF = thisPDF + Ap, where "+" is pose composition (both the
     * mean, and the covariance matrix are updated). */
    void operator+=(const CPose3DQuat& Ap);
    /** Makes: thisPDF = thisPDF + Ap, where "+" is pose composition (both the
     * mean, and the covariance matrix are updated) (see formulas in
     * jacobiansPoseComposition ). */
    void operator+=(const CPose3DQuatPDFGaussian& Ap);
    /** Makes: thisPDF = thisPDF - Ap, where "-" is pose inverse composition
     * (both the mean, and the covariance matrix are updated). */
    void operator-=(const CPose3DQuatPDFGaussian& Ap);

    /** Evaluates the PDF at a given point. */
    double evaluatePDF(const CPose3DQuat& x) const;

    /** Evaluates the ratio PDF(x) / PDF(MEAN), that is, the normalized PDF in
     * the range [0,1]. */
    double evaluateNormalizedPDF(const CPose3DQuat& x) const;

    /** Computes the Mahalanobis distance between the centers of two Gaussians.
     *  The variables with a variance exactly equal to 0 are not taken into
     * account in the process, but
     *   "infinity" is returned if the corresponding elements are not exactly
     * equal. */
    double mahalanobisDistanceTo(const CPose3DQuatPDFGaussian& theOther);

};  // End of class def.

bool operator==(
    const CPose3DQuatPDFGaussian& p1, const CPose3DQuatPDFGaussian& p2);
/** Pose composition for two 3D pose Gaussians  \sa
 * CPose3DQuatPDFGaussian::operator += */
CPose3DQuatPDFGaussian operator+(
    const CPose3DQuatPDFGaussian& x, const CPose3DQuatPDFGaussian& u);
/** Inverse pose composition for two 3D pose Gaussians  \sa
 * CPose3DQuatPDFGaussian::operator -= */
CPose3DQuatPDFGaussian operator-(
    const CPose3DQuatPDFGaussian& x, const CPose3DQuatPDFGaussian& u);

/** Dumps the mean and covariance matrix to a text stream. */
std::ostream& operator<<(std::ostream& out, const CPose3DQuatPDFGaussian& obj);

}  // namespace poses

namespace global_settings
{
/** If set to true (default), a Scaled Unscented Transform is used instead of a
 *linear approximation with Jacobians.
 * Affects to:
 *      - CPose3DQuatPDFGaussian::copyFrom(const CPose3DPDFGaussian &o)
 *      - CPose3DQuatPDFGaussianInf::copyFrom(const CPose3DPDFGaussianInf &o)
 */
void USE_SUT_EULER2QUAT_CONVERSION(bool value);
bool USE_SUT_EULER2QUAT_CONVERSION();
}  // namespace global_settings

}  // namespace mrpt