IdealWeightMeanRatio.hpp

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

    Copyright 2004 Sandia Corporation and Argonne National
    Laboratory.  Under the terms of Contract DE-AC04-94AL85000
    with Sandia Corporation, the U.S. Government retains certain
    rights in 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
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    diachin2@llnl.gov, djmelan@sandia.gov, mbrewer@sandia.gov,
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// -*- Mode : c++; tab-width: 3; c-tab-always-indent: t; indent-tabs-mode: nil; c-basic-offset: 3
// -*-

/*! \file IdealWeightMeanRatio.hpp

Header file for the MBMesquite::IdealWeightMeanRatio class

\author Michael Brewer
\author Todd Munson
\date   2002-11-11
 */

#ifndef IdealWeightMeanRatio_hpp
#define IdealWeightMeanRatio_hpp

#include "Mesquite.hpp"
#include "MsqError.hpp"
#include "ElementQM.hpp"
#include "AveragingQM.hpp"
#include "Vector3D.hpp"
#include "Matrix3D.hpp"
#include "Exponent.hpp"

namespace MBMesquite
{
/*! \class IdealWeightMeanRatio
  \brief Computes the mean ratio quality metric
  of given element.

  The metric does not use the sample point functionality or the
  compute_weighted_jacobian.  It evaluates the metric at
  the element vertices, and uses the isotropic ideal element.
  It does require a feasible region, and the metric needs
  to be maximized.
*/
class IdealWeightMeanRatio : public ElementQM, public AveragingQM
{
  public:
    MESQUITE_EXPORT IdealWeightMeanRatio()
        : AveragingQM( QualityMetric::LINEAR ), a2Con( 2.0 ), b2Con( -1.0 ), c2Con( 1.0 ), a3Con( 3.0 ), b3Con( -1.0 ),
          c3Con( 2.0 / 3.0 )
    {
    }

    //! virtual destructor ensures use of polymorphism during destruction
    MESQUITE_EXPORT virtual ~IdealWeightMeanRatio() {}

    virtual std::string get_name() const;

    //! 1 if metric should be minimized, -1 if metric should be maximized.
    virtual int get_negate_flag() const;

    virtual bool evaluate( PatchData& pd, size_t handle, double& value, MsqError& err );

    virtual bool evaluate_with_gradient( PatchData& pd,
                                         size_t handle,
                                         double& value,
                                         std::vector< size_t >& indices,
                                         std::vector< Vector3D >& gradient,
                                         MsqError& err );

    virtual bool evaluate_with_Hessian_diagonal( PatchData& pd,
                                                 size_t handle,
                                                 double& value,
                                                 std::vector< size_t >& indices,
                                                 std::vector< Vector3D >& gradient,
                                                 std::vector< SymMatrix3D >& Hessian,
                                                 MsqError& err );

    virtual bool evaluate_with_Hessian( PatchData& pd,
                                        size_t handle,
                                        double& value,
                                        std::vector< size_t >& indices,
                                        std::vector< Vector3D >& gradient,
                                        std::vector< Matrix3D >& Hessian,
                                        MsqError& err );

  private:
    // arrays used in Hessian computations
    // We allocate them here, so that one allocation only is done.
    // This gives a big computation speed increase.
    Vector3D mCoords[4];      // Vertex coordinates for the (decomposed) elements
    Vector3D mGradients[32];  // Gradient of metric with respect to the coords
    Matrix3D mHessians[80];   // Hessian of metric with respect to the coords
    double mMetrics[8];       // Metric values for the (decomposed) elements

    const double a2Con;
    const Exponent b2Con;
    const Exponent c2Con;

    const double a3Con;
    const Exponent b3Con;
    const Exponent c3Con;
};
}  // namespace MBMesquite

#endif  // IdealWeightMeanRatio_hpp