/* -*- mia-c++  -*-
 *
 * This file is part of MIA - a toolbox for medical image analysis
 * Copyright (c) Leipzig, Madrid 1999-2017 Gert Wollny
 *
 * MIA is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with MIA; if not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef mia_2d_ppmatrix_hh
#define mia_2d_ppmatrix_hh

#include <mia/2d/interpolator.hh>
#include <mia/2d/datafield.hh>
#include <mia/core/vector.hh>

NS_MIA_BEGIN

/**
   @ingroup registration
   @brief Precomputed matrix for the DivCurl regularization.

   Precomputed Matrix for the DivCurl regularization.
   This class stores the precomputed matrix for the divcurl regislarization
   of a spline based transformation.
   @todo Optimize like the 3D version that only stores the patch of required values instead
   of building the whole diagonals
*/
class EXPORT_2D C2DPPDivcurlMatrix
{
public:
       /**
          Construct the matrix according to the given coefficient field size, the used B-Spline kernel
          and the divergence and rotational weights
          \param size coefficient field size
          \param range full data range
          \param kernel B-Spline kernel used for the transformation
          \param wd weight for divergence
          \param wr weight for rotation (curl)
        */

       C2DPPDivcurlMatrix(const C2DBounds& size, const C2DFVector& range, const CSplineKernel& kernel,
                          double wd, double wr);

       ~C2DPPDivcurlMatrix();

       /**
          Given this matrix P and the coefficient field c evaluate the value for \f$c^T P c\f$
          \param coefficients B-Spline coefficient field c
          \returns \f$<c^T, P, c>\f$
        */
       double operator * (const C2DFVectorfield& coefficients) const;

       /**
          Given this matrix P and the coefficient field c evaluate the value for \f$c^T P c\f$
          \param coefficients B-Spline coefficient field c
          \returns \f$<c^T, P, c>\f$
        */
       double operator * (const T2DDatafield<C2DDVector>& coefficients) const;


       /**
          Given this matrix P and the coefficient field c evaluate the value for \f$c^T P c\f$
          \param coefficients B-Spline coefficient field c
          \param[out] gradient gradient of the divcurl cost
          \returns \f$<c^T, P, c>\f$
        */

       double evaluate(const C2DFVectorfield& coefficients, CDoubleVector& gradient) const;

       /**
          Given this matrix P and the coefficient field c evaluate the value for \f$c^T P c\f$
          Specialization for double valued vectors
          \param coefficients B-Spline coefficient field c
          \param[out] gradient gradient of the divcurl cost
          \returns \f$<c^T, P, c>\f$
       */
       double evaluate(const T2DDatafield<C2DDVector>& coefficients, CDoubleVector& gradient) const;

       /**
          \returns fild size this matrix was created for
        */
       const C2DBounds& get_size() const;

       /**
          re-initialize the matrix (if the values are changed)
        */
       void reset(const C2DBounds& size, const C2DFVector& range, const CSplineKernel& kernel,
                  double wd, double wr);
private:
       class C2DPPDivcurlMatrixImpl *impl;

};
NS_MIA_END

#endif
