gls.h

/*
 This Source Code Form is subject to the terms of the Mozilla Public
 License, v. 2.0. If a copy of the MPL was not distributed with this
 file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
 
#pragma once
 
#include "../../defines.h"
#include "../concepts.h"

#define GLS_PARAM_REQUIREMENTS ProvidesAlgebraicSphere<T>
 
#define GLS_DER_REQUIREMENTS ProvidesAlgebraicSphere<T>&& ProvidesImplicitPrimitiveDerivative<T>&& ProvidesGLSParam<T>
 
namespace Ponca
{

 
        Method published in \cite Mellado:2012:GLS
 
        This class assumes that the WeightFunc defines the accessor
        \code
            w.evalScale();
        \endcode
        in order to access to the evaluation scale, needed to compute the
        scale invariant GLS reparametrization (all *_normalized methods).
 
        Computed values:
        - tau(), eta() and kappa(): the GLS descriptor
        \f$ \left[ \tau \; \eta \; \kappa \right]\f$
        - tau_normalized(), eta_normalized() and kappa_normalized():
        the scale invariant GLS descriptor
        \f$ \left[ \frac{\tau}{t} \; \eta \; t\kappa \right]\f$
 
        Requirements:
        \verbatim ProvidesAlgebraicSphere \endverbatim
        Respects:
        \verbatim ProvidesGLSParam \endverbatim
    */

    template <class DataPoint, class _NFilter, typename T>
        requires GLS_PARAM_REQUIREMENTS
    class GLSParam : public T
    {
        PONCA_FITTING_DECLARE_DEFAULT_TYPES
    protected:
        Scalar m_fitness{0}; 
 
    public:
        PONCA_EXPLICIT_BASKET_CAST_OPERATORS(GLSParam, glsParam)
        PONCA_FITTING_DECLARE_FINALIZE
 
        /**************************************************************************/
        /* Use results                                                            */
        /**************************************************************************/
        /*! \brief Compute and return \f$ \tau \f$ */
        PONCA_MULTIARCH [[nodiscard]] inline Scalar tau() const
        {
            return Base::isNormalized() ? Base::m_uc : Base::m_uc / Base::prattNorm();
        }

        PONCA_MULTIARCH [[nodiscard]] inline VectorType eta() const { return Base::primitiveGradient(); }

        PONCA_MULTIARCH [[nodiscard]] inline Scalar kappa() const
        {
            return Scalar(2.) * (Base::isNormalized() ? Base::m_uq : Base::m_uq / Base::prattNorm());
        }

        PONCA_MULTIARCH [[nodiscard]] inline Scalar tau_normalized() const
        {
            return tau() / Base::getNeighborFilter().evalScale();
        }

        PONCA_MULTIARCH [[nodiscard]] inline VectorType eta_normalized() const { return eta(); }

        PONCA_MULTIARCH [[nodiscard]] inline Scalar kappa_normalized() const
        {
            return kappa() * Base::getNeighborFilter().evalScale();
        }

        PONCA_MULTIARCH [[nodiscard]] inline Scalar fitness() const { return m_fitness; }

        PONCA_MULTIARCH [[nodiscard]] inline Scalar compareTo(const GLSParam<DataPoint, _NFilter, T>& _other,
                                                              bool _useFitness = true) const
        {
            Scalar nTau     = this->tau_normalized() - _other.tau_normalized();
            Scalar nKappa   = this->kappa_normalized() - _other.kappa_normalized();
            Scalar nFitness = _useFitness ? this->fitness() - _other.fitness() : Scalar(0.);
 
            return nTau * nTau + nKappa * nKappa + nFitness * nFitness;
        }
 
    }; // class GLSParam

    template <class DataPoint, class _NFilter, int DiffType, typename T>
        requires GLS_DER_REQUIREMENTS
    class GLSDer : public T
    {
        PONCA_FITTING_DECLARE_DEFAULT_TYPES
        PONCA_FITTING_DECLARE_DEFAULT_DER_TYPES
    public:
        PONCA_EXPLICIT_BASKET_CAST_OPERATORS_DER(GLSDer, glsDer)
        PONCA_EXPLICIT_BASKET_CAST_OPERATORS_DER(GLSDer, geomVar)
 
        PONCA_MULTIARCH inline ScalarArray dtau() const;   
        PONCA_MULTIARCH inline VectorArray deta() const;   
        PONCA_MULTIARCH inline ScalarArray dkappa() const; 
 
        PONCA_MULTIARCH inline ScalarArray dtau_normalized()
            const; 
        PONCA_MULTIARCH inline VectorArray deta_normalized() const; 
        PONCA_MULTIARCH inline ScalarArray dkappa_normalized()
            const; 

        PONCA_MULTIARCH inline Scalar geomVar(Scalar wtau = Scalar(1), Scalar weta = Scalar(1),
                                              Scalar wkappa = Scalar(1)) const
            requires ProvidesScaleDerivative<T>;
    }; // class GLSScaleDer
 
#include "gls.hpp"
 
} // namespace Ponca