/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2004-2007 Hrvoje Jasak
     \\/     M anipulation  |
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.

    OpenFOAM 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 2 of the License, or (at your
    option) any later version.

    OpenFOAM 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 OpenFOAM; if not, write to the Free Software Foundation,
    Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

Application
    elasticPlasticNonLinTLSolidFoam

Description
    Finite volume structural solver employing an incremental strain total
    Lagrangian approach, with Mises plasticity.
    
    Valid for finite strains, finite displacements and finite rotations.

Author
    Philip Cardiff UCD
    
\*---------------------------------------------------------------------------*/

#include "fvCFD.H"
#include "constitutiveModel.H"
#include "solidContactFvPatchVectorField.H"

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

int main(int argc, char *argv[])
{
# include "setRootCase.H"
# include "createTime.H"
# include "createMesh.H"
# include "createFields.H"
# include "createHistory.H"
# include "readDivDSigmaExpMethod.H"
# include "readDivDSigmaNonLinExpMethod.H"

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

  Info<< "\nStarting time loop\n" << endl;

  while(runTime.loop())
    {
      Info<< "Time: " << runTime.timeName() << nl << endl;
      
#     include "readStressedFoamControls.H"

      int iCorr = 0;
      scalar initialResidual = 0;
      lduMatrix::solverPerformance solverPerf;
      scalar relativeResidual = GREAT;
      lduMatrix::debug=0;
      
      do
        {
	  DU.storePrevIter();

#         include "calculateDivDSigmaExp.H"
#         include "calculateDivDSigmaNonLinExp.H"

	  // incremental form
	  // linear momentum conservation
	  // ensuring conservation of total momentum
	  fvVectorMatrix DUEqn
            (
	     fvm::d2dt2(rho, DU)
	     ==
	     fvm::laplacian(2*muf + lambdaf, DU, "laplacian(DDU,DU)")
	     + divDSigmaExp
	     + divDSigmaNonLinExp
	     //- fvc::div(2*mu*DEpsilonP, "div(sigma)")
	     - fvc::div(2*muf*( mesh.Sf() & fvc::interpolate(DEpsilonP)) )
	     );

// 	  if(thirdOrderCorrection)
// 	    {
// #             include "calculateThirdOrderDissipativeTerm.H"
// 	      DUEqn -= divThirdOrderTerm;
// 	    }

	  if(largeStrainOverRelax)
	    {
	      // the terms (gradDU & gradU.T()) and (gradU & gradDU.T())
	      // are linearly dependent of DU and represent initial displacement effect
	      // which can cause convergence difficulties when treated explicitly
	      // so we implicitly over-relax with gradU & gradDU here
	      // which tends to help convergence
	      // this should improve convergence when gradU is large
	      // but maybe not execution time
	      DUEqn -=
		fvm::laplacian((2*mu + lambda)*gradU, DU, "laplacian(DDU,DU)")
		- fvc::div( (2*mu + lambda)*(gradU&gradDU), "div(sigma)");
	      //- fvc::div(mesh.magSf()*( (muf+lambdaf) * (n & fvc::interpolate( gradU & gradDU) ) ) );
	    }

	  if(nonLinearSemiImplicit)
	    {
	      // experimental
	      // we can treat the nonlinear term (gradDU & gradDU.T()) in a
	      // semi-implicit over-relaxed manner
	      // this should improve convergence when gradDU is large
	      // but maybe not execution time
	      DUEqn -=
	      fvm::laplacian((2*mu + lambda)*gradDU, DU, "laplacian(DDU,DU)")
	      - fvc::div( (2*mu + lambda)*(gradDU&gradDU), "div(sigma)");
	      // try use old gradDU as an OK guess, as gradDU will oscillate
	      // and might make the convergence worse
// 	      DUEqn -=
// 	      fvm::laplacian((2*mu + lambda)*gradDU.oldTime(), DU, "laplacian(DDU,DU)")
// 	      - fvc::div( (2*mu + lambda)*(gradDU.oldTime()&gradDU), "div(sigma)");
	    }

	  solverPerf = DUEqn.solve();

	  if(iCorr == 0)
	    {
	      initialResidual = solverPerf.initialResidual();
	    }

	  if(aitkenRelax)
	    {
#             include "aitkenRelaxation.H"
	    }
	  else
	    {	  
	      DU.relax();
	    }

	  gradDU = fvc::grad(DU);

	  // correct plasticty term
	  rheology.correct();

#         include "calculateDEpsilonDSigma.H"
#         include "calculateRelativeResidual.H"
	  
	  if(iCorr % infoFrequency == 0)
	    {
	      Info << "\tTime " << runTime.value()
		   << ", Corrector " << iCorr
		   << ", Solving for " << DU.name()
		   << " using " << solverPerf.solverName()
		   << ", res = " << solverPerf.initialResidual()
		   << ", rel res = " << relativeResidual;
	      if(aitkenRelax) Info << ", aitken = " << aitkenTheta;
	      Info << ", iters = " << solverPerf.nIterations() << endl;
	    }
	}
      while
	(
	 iCorr++ == 0
	 ||
	 (//solverPerf.initialResidual() > convergenceTolerance
	  relativeResidual > convergenceTolerance
	  &&
	  iCorr < nCorr)
	 );
      
      Info << nl << "Time " << runTime.value() << ", Solving for " << DU.name() 
	   << ", Initial residual = " << initialResidual 
	   << ", Final residual = " << solverPerf.initialResidual()
	   << ", Relative residual = " << relativeResidual
	   << ", No outer iterations " << iCorr
	   << nl << "ExecutionTime = " << runTime.elapsedCpuTime() << " s"
	   << "  ClockTime = " << runTime.elapsedClockTime() << " s" 
	   << endl;
      
      // update total quantities
      U += DU;
      gradU += gradDU;
      epsilon += DEpsilon;
      epsilonP += rheology.DEpsilonP();
      sigma += DSigma;
      rheology.updateYieldStress();
      rho = rho/det(I+gradU);

#     include "writeFields.H"
#     include "writeHistory.H"

      Info<< "ExecutionTime = "
	  << runTime.elapsedCpuTime()
	  << " s\n\n" << endl;
    }
  
  Info<< "End\n" << endl;
  
  return(0);
}


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