TUntangleMu.hpp

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/* *****************************************************************
    MESQUITE -- The Mesh Quality Improvement Toolkit

    Copyright 2010 Sandia National Laboratories.  Developed at the
    University of Wisconsin--Madison under SNL contract number
    624796.  The U.S. Government and the University of Wisconsin
    retain certain rights to this software.

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    (lgpl.txt) along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    (2010) [email protected]

  ***************************************************************** */

/** \file TUntangleMu.hpp
 *  \brief
 *  \author Jason Kraftcheck
 */

#ifndef MSQ_T_UNTANGLE_MU_HPP
#define MSQ_T_UNTANGLE_MU_HPP

#include "Mesquite.hpp"
#include "TMetric.hpp"

namespace MBMesquite
{

/**\brief Composite untangle metric
 *
 * This metric should be combined with TRel2DSize or TRel2DShapeSize
 * to produce a concrete untangle metric.
 *
 * \f$ \mu^\prime(T) = \frac{1}{8}(|d| - d)^3 \f$
 * \f$ d(T) = \sigma - \epsilon - \mu(T()) \f$
 *
 */
class TUntangleMu : public TMetric
{
  private:
    TMetric* mBaseMetric;
    double mConstant;

  public:
    TUntangleMu( TMetric* base, double sigma = 1.0 )
        : mBaseMetric( base ), mConstant( 0.99 * sigma ) /* default epsilon is 0.01*sigma */
    {
    }

    TUntangleMu( TMetric* base, double sigma, double epsilon ) : mBaseMetric( base ), mConstant( sigma - epsilon ) {}

    MESQUITE_EXPORT virtual ~TUntangleMu();

    MESQUITE_EXPORT virtual std::string get_name() const;

    MESQUITE_EXPORT virtual bool evaluate( const MsqMatrix< 2, 2 >& T, double& result, MsqError& err );

    MESQUITE_EXPORT virtual bool evaluate_with_grad( const MsqMatrix< 2, 2 >& T,
                                                     double& result,
                                                     MsqMatrix< 2, 2 >& deriv_wrt_T,
                                                     MsqError& err );

    MESQUITE_EXPORT virtual bool evaluate_with_hess( const MsqMatrix< 2, 2 >& T,
                                                     double& result,
                                                     MsqMatrix< 2, 2 >& deriv_wrt_T,
                                                     MsqMatrix< 2, 2 > second_wrt_T[3],
                                                     MsqError& err );

    MESQUITE_EXPORT virtual bool evaluate( const MsqMatrix< 3, 3 >& T, double& result, MsqError& err );

    MESQUITE_EXPORT virtual bool evaluate_with_grad( const MsqMatrix< 3, 3 >& T,
                                                     double& result,
                                                     MsqMatrix< 3, 3 >& deriv_wrt_T,
                                                     MsqError& err );

    MESQUITE_EXPORT virtual bool evaluate_with_hess( const MsqMatrix< 3, 3 >& T,
                                                     double& result,
                                                     MsqMatrix< 3, 3 >& deriv_wrt_T,
                                                     MsqMatrix< 3, 3 > second_wrt_T[6],
                                                     MsqError& err );

  private:
    template < unsigned D >
    inline bool eval( const MsqMatrix< D, D >& T, double& result, MsqError& err );
    template < unsigned D >
    inline bool grad( const MsqMatrix< D, D >& T, double& result, MsqMatrix< D, D >& first, MsqError& err );
    template < unsigned D >
    inline bool hess( const MsqMatrix< D, D >& T,
                      double& result,
                      MsqMatrix< D, D >& first,
                      MsqMatrix< D, D >* second,
                      MsqError& err );
};

}  // namespace MBMesquite

#endif