source: issm/trunk-jpl/src/c/solutionsequences/solutionsequence_nonlinear.cpp@ 24679

/*!\file: solutionsequence_nonlinear.cpp
 * \brief: core of a non-linear solution, using fixed-point method 
 */ 

#include "./solutionsequences.h"
#include "../toolkits/toolkits.h"
#include "../classes/classes.h"
#include "../shared/shared.h"
#include "../modules/modules.h"

void solutionsequence_nonlinear(FemModel* femmodel,bool conserve_loads){

        /*intermediary: */
        Matrix<IssmDouble>* Kff = NULL;
        Matrix<IssmDouble>* Kfs = NULL;
        Vector<IssmDouble>* ug  = NULL;
        Vector<IssmDouble>* uf  = NULL;
        Vector<IssmDouble>* old_uf = NULL;
        Vector<IssmDouble>* pf  = NULL;
        Vector<IssmDouble>* df  = NULL;
        Vector<IssmDouble>* ys  = NULL;

        Loads* savedloads=NULL;
        bool converged;
        int constraints_converged;
        int num_unstable_constraints;
        int count;

        /*parameters:*/
        int min_mechanical_constraints;
        int max_nonlinear_iterations;
        int configuration_type;
        IssmDouble eps_res,eps_rel,eps_abs;

        /*Recover parameters: */
        femmodel->parameters->FindParam(&min_mechanical_constraints,StressbalanceRiftPenaltyThresholdEnum);
        femmodel->parameters->FindParam(&max_nonlinear_iterations,StressbalanceMaxiterEnum);
        femmodel->parameters->FindParam(&eps_res,StressbalanceRestolEnum);
        femmodel->parameters->FindParam(&eps_rel,StressbalanceReltolEnum);
        femmodel->parameters->FindParam(&eps_abs,StressbalanceAbstolEnum);
        femmodel->parameters->FindParam(&configuration_type,ConfigurationTypeEnum);
        femmodel->UpdateConstraintsx();

        /*Were loads requested as output? : */
        if(conserve_loads){
                savedloads = static_cast<Loads*>(femmodel->loads->Copy());
        }

        count=0;
        converged=false;

        /*Start non-linear iteration using input velocity: */
        GetSolutionFromInputsx(&ug,femmodel);
        Reducevectorgtofx(&uf, ug, femmodel->nodes,femmodel->parameters);

        //Update once again the solution to make sure that vx and vxold are similar (for next step in transient or steadystate)
        InputUpdateFromConstantx(femmodel,converged,ConvergedEnum);
        InputUpdateFromSolutionx(femmodel,ug);

        // allocate the matrices once and reuce them per iteration
        AllocateSystemMatricesx(&Kff,&Kfs,&df,&pf,femmodel);

        for(;;){

                //save pointer to old velocity
                delete old_uf;old_uf=uf;
                delete ug;

                SystemMatricesx(&Kff,&Kfs,&pf,&df,NULL,femmodel, true);
                CreateNodalConstraintsx(&ys,femmodel->nodes);
                Reduceloadx(pf, Kfs, ys);
                femmodel->profiler->Start(SOLVER);
                Solverx(&uf, Kff, pf, old_uf, df, femmodel->parameters);
                femmodel->profiler->Stop(SOLVER);
        
                Mergesolutionfromftogx(&ug, uf,ys,femmodel->nodes,femmodel->parameters);delete ys;

                convergence(&converged,Kff,pf,uf,old_uf,eps_res,eps_rel,eps_abs);
                InputUpdateFromConstantx(femmodel,converged,ConvergedEnum);
                InputUpdateFromSolutionx(femmodel,ug);

                ConstraintsStatex(&constraints_converged,&num_unstable_constraints,femmodel);
                if(VerboseConvergence()) _printf0_("   number of unstable constraints: " << num_unstable_constraints << "\n");

                //rift convergence
                if (!constraints_converged) {
                        if (converged){
                                if (num_unstable_constraints <= min_mechanical_constraints) converged=true;
                                else converged=false;
                        }
                }
                
                /*Increase count: */
                count++;
                if(converged==true){
                        femmodel->results->AddResult(new GenericExternalResult<IssmDouble>(femmodel->results->Size()+1,StressbalanceConvergenceNumStepsEnum,count));
                        break;
                }
                if(count>=max_nonlinear_iterations){
                        _printf0_("   maximum number of nonlinear iterations (" << max_nonlinear_iterations << ") exceeded\n"); 
                        converged=true;
                        femmodel->results->AddResult(new GenericExternalResult<IssmDouble>(femmodel->results->Size()+1,StressbalanceConvergenceNumStepsEnum,max_nonlinear_iterations));
                        InputUpdateFromConstantx(femmodel,converged,ConvergedEnum);
                        InputUpdateFromSolutionx(femmodel,ug);          
                        break;
                }

                // Set the matrix entries to zero if we do an other iteration
                Kff->SetZero();
                Kfs->SetZero();
                df->Set(0);
                pf->Set(0);
        }

        // delete matrices after the iteration loop
        delete Kff; delete pf; delete df;
        delete Kfs;

        if(VerboseConvergence()) _printf0_("\n   total number of iterations: " << count << "\n");

        /*clean-up*/
        if(conserve_loads){
                delete femmodel->loads;
                int index=femmodel->AnalysisIndex(configuration_type);
                femmodel->loads_list[index]=savedloads;
                femmodel->loads=savedloads;
        }
        delete uf;
        delete ug;
        delete old_uf;
}