/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | foam-extend: Open Source CFD
   \\    /   O peration     | Version:     4.0
    \\  /    A nd           | Web:         http://www.foam-extend.org
     \\/     M anipulation  | For copyright notice see file Copyright
-------------------------------------------------------------------------------
License
    This file is part of foam-extend.

    foam-extend 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.

    foam-extend 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 foam-extend.  If not, see <http://www.gnu.org/licenses/>.

Application
    elasticPlasticNonLinULSolidFoam

Description
    Finite volume structural solver employing a incremental strain updated
    Lagrangian approach.

    Valid for small strains, finite displacements and finite rotations.

    Note: the reason the solver is not strictly valid for large strains is
    because the constitutive stiffness tensor is not rotated.
    For an updated Lagrangian solver which does rotate the stiffness tensor, and
    hence is strictly Valid for large strains, use
    elasticOrthoNonLinULSolidFoam.

Author
    Philip Cardiff UCD
    Aitken relaxation by T. Tang DTU

\*---------------------------------------------------------------------------*/

#include "fvCFD.H"
#include "constitutiveModel.H"
#include "volPointInterpolation.H"
#include "pointPatchInterpolation.H"
#include "primitivePatchInterpolation.H"
#include "pointFields.H"
#include "twoDPointCorrector.H"
#include "leastSquaresVolPointInterpolation.H"
#include "transformGeometricField.H"
#include "solidContactFvPatchVectorField.H"
#include "pointMesh.H"
#include "symmetryPolyPatch.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"
# include "readMoveMeshMethod.H"
# include "findGlobalFaceZones.H"

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

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

    while(runTime.loop())
    {
        Info<< "Time = " << runTime.timeName() << nl << endl;

#       include "readSolidMechanicsControls.H"

        int iCorr = 0;
        lduSolverPerformance solverPerf;
        scalar initialResidual = 0;
        scalar relativeResidual = 1.0;
        lduMatrix::debug = 0;


        do
        {
            DU.storePrevIter();

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

            // Updated lagrangian large strain momentum equation
            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(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)");
            }

            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();

            // correct elastic properties
            // for nonlinear elastic materials
            //mu = rheology.newMu();
            //lambda = rheology.newLambda();
            //muf = fvc::interpolate(mu);
            //lambdaf = fvc::interpolate(lambda);

#           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++ < 2
            ||
            (
                //solverPerf.initialResidual() > convergenceTolerance
                relativeResidual > convergenceTolerance
             && iCorr < nCorr
            )
        );

        Info<< nl << "Time " << runTime.value() << ", Solving for " << DU.name()
            << ", Initial residual = " << initialResidual
            << ", Final residual = " << solverPerf.initialResidual()
            << ", Final rel residual = " << relativeResidual
            << ", No outer iterations " << iCorr << endl;

        rheology.updateYieldStress();

        U += DU;
        epsilon += DEpsilon;
        epsilonP += DEpsilonP;
        sigma += DSigma;

#       include "moveMesh.H"
#       include "rotateFields.H"
#       include "writeFields.H"
#       include "writeHistory.H"

        Info<< nl << "ExecutionTime = " << runTime.elapsedCpuTime() << " s"
            << "  ClockTime = " << runTime.elapsedClockTime() << " s"
            << endl;
    }

    Info<< "End\n" << endl;

    return(0);
}


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