text: /*************************************************************************
   *                                                                       *
   * Vega FEM Simulation Library Version 4.0                               *
   *                                                                       *
   * "elasticForceModel" library , Copyright (C) 2007 CMU, 2009 MIT,       *
   *                                                       2018 USC        *
   * All rights reserved.                                                  *
   *                                                                       *
   * Code author: Jernej Barbic                                            *
   * http://www.jernejbarbic.com/vega                                      *
   *                                                                       *
   * Research: Jernej Barbic, Hongyi Xu, Yijing Li,                        *
   *           Danyong Zhao, Bohan Wang,                                   *
   *           Fun Shing Sin, Daniel Schroeder,                            *
   *           Doug L. James, Jovan Popovic                                *
   *                                                                       *
   * Funding: National Science Foundation, Link Foundation,                *
   *          Singapore-MIT GAMBIT Game Lab,                               *
   *          Zumberge Research and Innovation Fund at USC,                *
   *          Sloan Foundation, Okawa Foundation,                          *
   *          USC Annenberg Foundation                                     *
   *                                                                       *
   * This library is free software; you can redistribute it and/or         *
   * modify it under the terms of the BSD-style license that is            *
   * included with this library in the file LICENSE.txt                    *
   *                                                                       *
   * 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 file     *
   * LICENSE.TXT for more details.                                         *
   *                                                                       *
   *************************************************************************/
  
  /*
    Force model for a reduced mass spring system, with Hessian.
    The reduced force and reduced stiffness matrix are computed in the 
    high-dimensional space, and then projected:
    fq = U^T f(U*q)
  */
  
  #ifndef _REDUCEDMASSSPRINGSYSTEMFORCEMODELWITHHESSIAN_H_
  #define _REDUCEDMASSSPRINGSYSTEMFORCEMODELWITHHESSIAN_H_
  
  #include "reducedMassSpringSystemForceModel.h"
  #include "reducedForceModelWithHessian.h"
  
  class ReducedMassSpringSystemForceModelWithHessian : public ReducedMassSpringSystemForceModel, public ReducedForceModelWithHessian
  {
  public:
    ReducedMassSpringSystemForceModelWithHessian(MassSpringSystem * massSpringSystem, ModalMatrix * modalMatrix);
    virtual ~ReducedMassSpringSystemForceModelWithHessian();
  
    virtual void GetTangentHessianTensor(double * q, double * tangentHessianTensor);
    virtual void GetStiffnessMatrixCorrection(double * u, double * du, double * dK);
  
  protected:
    double * bufferTangentMatrix;
  };
  
  #endif
  
  