Example #1
0
PetscErrorCode PCBDDCSetupFETIDPPCContext(Mat fetimat, FETIDPPC_ctx fetidppc_ctx)
{
  FETIDPMat_ctx  mat_ctx;
  PC_IS          *pcis;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  ierr = MatShellGetContext(fetimat,(void**)&mat_ctx);CHKERRQ(ierr);
  /* get references from objects created when setting up feti mat context */
  ierr = PetscObjectReference((PetscObject)mat_ctx->lambda_local);CHKERRQ(ierr);
  fetidppc_ctx->lambda_local = mat_ctx->lambda_local;
  ierr = PetscObjectReference((PetscObject)mat_ctx->B_Ddelta);CHKERRQ(ierr);
  fetidppc_ctx->B_Ddelta = mat_ctx->B_Ddelta;
  ierr = PetscObjectReference((PetscObject)mat_ctx->l2g_lambda);CHKERRQ(ierr);
  fetidppc_ctx->l2g_lambda = mat_ctx->l2g_lambda;
  /* create local Schur complement matrix */
  pcis = (PC_IS*)fetidppc_ctx->pc->data;
  ierr = MatCreateSchurComplement(pcis->A_II,pcis->A_II,pcis->A_IB,pcis->A_BI,pcis->A_BB,&fetidppc_ctx->S_j);CHKERRQ(ierr);
  ierr = MatSchurComplementSetKSP(fetidppc_ctx->S_j,pcis->ksp_D);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}
PetscErrorCode BSSCR_DRIVER_flex( KSP ksp, Mat stokes_A, Vec stokes_x, Vec stokes_b, Mat approxS, KSP ksp_K,
                                  MatStokesBlockScaling BA, PetscTruth sym, KSP_BSSCR * bsscrp_self )
{
    char name[PETSC_MAX_PATH_LEN];
    char ubefore[100];
    char uafter[100];
    char pbefore[100];
    char pafter[100];
    PetscTruth flg, flg2, truth, useAcceleratingSmoothingMG, useFancySmoothingMG;
    PetscTruth usePreviousGuess, useNormInfStoppingConditions, useNormInfMonitor, found, extractMats;
    Mat K,G,D,C;
    Vec u,p,f,h;
    Mat S;
    Vec h_hat,t,t2,q,v;

    KSP ksp_inner;
    KSP ksp_S;
    KSP ksp_cleaner;
    KSPType ksp_inner_type;
        
    PetscTruth has_cnst_nullspace;
    PC pc_S, pc_MG, pcInner;
    PetscInt monitor_index,max_it,min_it;
    Vec nsp_vec = PETSC_NULL; 
        
    PetscReal scr_rtol;
    PetscReal inner_rtol;
    PetscReal vSolver_rtol;
        
    PetscScalar uNormInf, pNormInf;
    PetscScalar uNorm, pNorm, rNorm, fNorm;
    PetscInt  uSize, pSize;
    PetscInt    lmin,lmax;
    PetscInt  iterations;
    PetscReal   min,max;
    PetscReal p_sum;

    MGContext mgCtx;
    PC shellPC;

    double t0, t1;
    double mgSetupTime, scrSolveTime, a11SingleSolveTime, solutionAnalysisTime;
    Index nx,ny,nz;
    PetscInt j,start,end;

    static int been_here = 0;  /* Ha Ha Ha !! */

    /* get sub matrix / vector objects */
    MatNestGetSubMat( stokes_A, 0,0, &K );
    MatNestGetSubMat( stokes_A, 0,1, &G );
    MatNestGetSubMat( stokes_A, 1,0, &D );
    MatNestGetSubMat( stokes_A, 1,1, &C );
        
    VecNestGetSubVec( stokes_x, 0, &u );
    VecNestGetSubVec( stokes_x, 1, &p );
        
    VecNestGetSubVec( stokes_b, 0, &f );
    VecNestGetSubVec( stokes_b, 1, &h );

    /* PetscPrintf( PETSC_COMM_WORLD,  "\t Adress of stokes_x is %p\n", stokes_x); */
    /* VecNorm( u, NORM_2, &uNorm ); */
    /* PetscPrintf( PETSC_COMM_WORLD,  "\t u Norm is %.6e in %s: address is %p\n",uNorm,__func__,u); */
    /* VecNorm( p, NORM_2, &pNorm ); */
    /* PetscPrintf( PETSC_COMM_WORLD,  "\t p Norm is %.6e in %s: addres is %p\n",pNorm,__func__,p); */
    /* Create Schur complement matrix */
        
    //MatCreateSchurFromBlock( stokes_A, 0.0, "MatSchur_A11", &S );
    MatCreateSchurComplement(K,K,G,D,C, &S);
    /* configure inner solver */
    if (ksp_K!=PETSC_NULL) {
        MatSchurComplementSetKSP( S, ksp_K );
        MatSchurComplementGetKSP( S, &ksp_inner );
    }
    else {
        abort();
        MatSchurComplementGetKSP( S, &ksp_inner );
        KSPSetType( ksp_inner, "cg" );
    }
    KSPGetPC( ksp_inner, &pcInner );

    /* If we're using multigrid, replace the preconditioner here
       so we get the same options prefix. */

    if(bsscrp_self->mg) {
        mgSetupTime=setupMG( bsscrp_self, ksp_inner, pcInner, K, &mgCtx );
    }

    /* SETFROMOPTIONS MIGHT F**K MG UP */
    KSPSetOptionsPrefix( ksp_inner, "A11_" );
    KSPSetFromOptions( ksp_inner );

    useNormInfStoppingConditions = PETSC_FALSE;
    PetscOptionsGetTruth( PETSC_NULL ,"-A11_use_norm_inf_stopping_condition", &useNormInfStoppingConditions, &found );
    if(useNormInfStoppingConditions) 
        BSSCR_KSPSetNormInfConvergenceTest( ksp_inner ); 

    useNormInfMonitor = PETSC_FALSE; 
    PetscOptionsGetTruth( PETSC_NULL, "-A11_ksp_norm_inf_monitor", &useNormInfMonitor, &found );
    if(useNormInfMonitor) 
        KSPMonitorSet( ksp_inner, BSSCR_KSPNormInfMonitor, PETSC_NULL, PETSC_NULL );
        
    useNormInfMonitor = PETSC_FALSE; 
    PetscOptionsGetTruth( PETSC_NULL, "-A11_ksp_norm_inf_to_norm_2_monitor", &useNormInfMonitor, &found );
    if(useNormInfMonitor) 
        KSPMonitorSet( ksp_inner, BSSCR_KSPNormInfToNorm2Monitor, PETSC_NULL, PETSC_NULL );

    /* create right hand side */
    /* h_hat = G'*inv(K)*f - h */
    MatGetVecs(K,PETSC_NULL,&t);
    MatGetVecs( S, PETSC_NULL, &h_hat );

    KSPSetOptionsPrefix( ksp_inner, "A11_" );
    KSPSetFromOptions( ksp_inner );

    KSPSolve(ksp_inner,f,t);/* t=f/K */
    //bsscr_writeVec( t, "ts", "Writing t vector");
    MatMult(D,t,h_hat);/* G'*t */
    VecAXPY(h_hat, -1.0, h);/* h_hat = h_hat - h */
    Stg_VecDestroy(&t);
    //bsscr_writeVec( h_hat, "h_hat", "Writing h_hat Vector in Solver");
    //MatSchurApplyReductionToVecFromBlock( S, stokes_b, h_hat );
        
    /* create solver for S p = h_hat */

    KSPCreate( PETSC_COMM_WORLD, &ksp_S );
    KSPSetOptionsPrefix( ksp_S, "scr_");
    Stg_KSPSetOperators( ksp_S, S,S, SAME_NONZERO_PATTERN );
    KSPSetType( ksp_S, "cg" );
        
    /* Build preconditioner for S */
    KSPGetPC( ksp_S, &pc_S );
    BSSCR_BSSCR_StokesCreatePCSchur2( K,G,D,C,approxS,pc_S,sym, bsscrp_self );

    KSPSetFromOptions(ksp_S);

    /* Set specific monitor test */
    KSPGetTolerances( ksp_S, PETSC_NULL, PETSC_NULL, PETSC_NULL, &max_it );
    //BSSCR_KSPLogSetMonitor( ksp_S, max_it, &monitor_index );
        
    /* Pressure / Velocity Solve */   
    scrSolveTime = MPI_Wtime();
    PetscPrintf( PETSC_COMM_WORLD, "\t* Pressure / Velocity Solve \n");

    usePreviousGuess = PETSC_FALSE; 
    if(been_here)
        PetscOptionsGetTruth( PETSC_NULL, "-scr_use_previous_guess", &usePreviousGuess, &found );
    
    if(usePreviousGuess) {   /* Note this should actually look at checkpoint information */
        KSPSetInitialGuessNonzero( ksp_S, PETSC_TRUE );
    }
    else {
        KSPSetInitialGuessNonzero( ksp_S, PETSC_FALSE );
    }
    
    //KSPSetRelativeRhsConvergenceTest( ksp_S );

    useNormInfStoppingConditions = PETSC_FALSE;
    PetscOptionsGetTruth( PETSC_NULL ,"-scr_use_norm_inf_stopping_condition", &useNormInfStoppingConditions, &found );
    if(useNormInfStoppingConditions) 
        BSSCR_KSPSetNormInfConvergenceTest(ksp_S); 

    useNormInfMonitor = PETSC_FALSE; 
    PetscOptionsGetTruth( PETSC_NULL, "-scr_ksp_norm_inf_monitor", &useNormInfMonitor, &found );
    if(useNormInfMonitor) 
        KSPMonitorSet( ksp_S, BSSCR_KSPNormInfToNorm2Monitor, PETSC_NULL, PETSC_NULL );


    PetscPrintf( PETSC_COMM_WORLD, "\t* KSPSolve( ksp_S, h_hat, p )\n");
    /* if h_hat needs to be fixed up ..take out any nullspace vectors here */
    /* we want to check that there is no "noise" in the null-space in the h vector */
    /* this causes problems when we are trying to solve a Jacobian system when the Residual is almost converged */
    if(bsscrp_self->check_pressureNS){
        bsscrp_self->buildPNS(ksp);/* build and set nullspace vectors on bsscr - which is on ksp (function pointer is set in KSPSetUp_BSSCR */
    }

    PetscScalar norm, a, a1, a2, hnorm, pnorm, gnorm;
    MatNorm(G,NORM_INFINITY,&gnorm);
    VecNorm(h_hat, NORM_2, &hnorm);
    hnorm=hnorm/gnorm;

    if((hnorm < 1e-6) && (hnorm > 1e-20)){
        VecScale(h_hat,1.0/hnorm);
    }
    /* test to see if v or t are in nullspace of G and orthogonalize wrt h_hat if needed */
    KSPRemovePressureNullspace_BSSCR(ksp, h_hat);
    /***************************************/
    /* set convergence test to use min_it */
    found = PETSC_FALSE;
    min_it = 0;
    PetscOptionsGetInt( PETSC_NULL,"-scr_ksp_set_min_it_converge", &min_it, &found);
    if(found && min_it > 0){
        BSSCR_KSPSetConvergenceMinIts(ksp_S, min_it, bsscrp_self);
    }
    KSPSolve( ksp_S, h_hat, p );
    sprintf(pafter,"psafter_%d",been_here);
    bsscr_writeVec( p, pafter, "Writing p Vector in Solver");
    /***************************************/
    if((hnorm < 1e-6) && (hnorm > 1e-20)){
        VecScale(h_hat,hnorm);
        VecScale(p,hnorm);
    }
    KSPRemovePressureNullspace_BSSCR(ksp, p);


    scrSolveTime =  MPI_Wtime() - scrSolveTime;
    PetscPrintf( PETSC_COMM_WORLD, "\n\t* KSPSolve( ksp_S, h_hat, p )  Solve  Finished in time: %lf seconds\n\n", scrSolveTime);
    /* Resolve with this pressure to obtain solution for u */
        
    /* obtain solution for u */       
    VecDuplicate( u, &t );
    MatMult( G, p, t);
    VecAYPX( t, -1.0, f ); /* t <- -t + f */
    MatSchurComplementGetKSP( S, &ksp_inner );
        
 
    a11SingleSolveTime = MPI_Wtime();         /* ----------------------------------  Final V Solve */
        
    if(usePreviousGuess)      
        KSPSetInitialGuessNonzero( ksp_inner, PETSC_TRUE ); 

    KSPSetOptionsPrefix( ksp_inner, "backsolveA11_" );
    KSPSetFromOptions( ksp_inner );
    KSPSolve( ksp_inner, t, u );       /* Solve, then restore default tolerance and initial guess */          


    a11SingleSolveTime = MPI_Wtime() - a11SingleSolveTime;            /* ------------------ Final V Solve */

        
    PetscPrintf( PETSC_COMM_WORLD,  "\n\nSCR Solver Summary:\n\n");
  
    if(bsscrp_self->mg)
        PetscPrintf( PETSC_COMM_WORLD, "  Multigrid setup:        = %.4g secs \n", mgSetupTime);

    KSPGetIterationNumber( ksp_S, &iterations);
    PetscPrintf( PETSC_COMM_WORLD,     "  Pressure Solve:         = %.4g secs / %d its\n", scrSolveTime, iterations);
    KSPGetIterationNumber( ksp_inner, &iterations);
    PetscPrintf( PETSC_COMM_WORLD,     "  Final V Solve:          = %.4g secs / %d its\n\n", a11SingleSolveTime, iterations);
    
    /* Analysis of solution:
       This can be somewhat time consuming as it requires allocation / de-allocation, 
       computing vector norms etc. So we make it optional..
       This should be put into a proper KSP  monitor now?
    */        
    flg = PETSC_TRUE;
    PetscOptionsGetTruth( PETSC_NULL, "-scr_ksp_solution_summary", &flg, &found );
        
    if(flg) {
        
        solutionAnalysisTime = MPI_Wtime();
        
        VecGetSize( u, &uSize ); 
        VecGetSize( p, &pSize );
        
        VecDuplicate( u, &t2 );
        MatMult( K, u, t2);
        VecAYPX( t2, -1.0, t ); /* t2 <- -t2 + t  ... should be the formal residual vector */
        
        VecNorm( t2, NORM_2, &rNorm );      
        VecNorm( f,  NORM_2, &fNorm );      
        
        PetscPrintf( PETSC_COMM_WORLD,  "  |f - K u - G p|/|f|     = %.6e\n", rNorm/fNorm );
                
        VecDuplicate( p, &q );
        MatMult( D, u, q );
        VecNorm( u, NORM_2, &uNorm );       
        VecNorm( q, NORM_2, &rNorm );       
        
        PetscPrintf( PETSC_COMM_WORLD,  "  |G^T u|_2/|u|_2         = %.6e\n", sqrt( (double) uSize / (double) pSize ) * rNorm / uNorm);
        
        VecNorm( q, NORM_INFINITY, &rNorm );
        
        PetscPrintf( PETSC_COMM_WORLD,  "  |G^T u|_infty/|u|_2     = %.6e\n", sqrt( (double) uSize ) * rNorm / uNorm);

        VecNorm( u, NORM_INFINITY, &uNormInf );
        VecNorm( u, NORM_2,        &uNorm );
        VecGetSize( u, &uSize );
        
        VecNorm( p, NORM_INFINITY, &pNormInf );
        VecNorm( p, NORM_2,        &pNorm );
        
        PetscPrintf( PETSC_COMM_WORLD,  "  |u|_{\\infty}  = %.6e , u_rms = %.6e\n", 
                     uNormInf, uNorm / sqrt( (double) uSize ) );
                
        PetscPrintf( PETSC_COMM_WORLD,  "  |p|_{\\infty}  = %.6e , p_rms = %.6e\n",
                     pNormInf, pNorm / sqrt( (double) pSize ) );

        VecMax( u, &lmax, &max );
        VecMin( u, &lmin, &min );
        PetscPrintf( PETSC_COMM_WORLD,  "  min/max(u)    = %.6e [%d] / %.6e [%d]\n",min,lmin,max,lmax);

        VecMax( p, &lmax, &max );
        VecMin( p, &lmin, &min );
        PetscPrintf( PETSC_COMM_WORLD,  "  min/max(p)    = %.6e [%d] / %.6e [%d]\n",min,lmin,max,lmax);
       
        VecSum( p, &p_sum );
        PetscPrintf( PETSC_COMM_WORLD,  "  \\sum_i p_i    = %.6e \n", p_sum );
        
        solutionAnalysisTime = MPI_Wtime() - solutionAnalysisTime;
        
        PetscPrintf( PETSC_COMM_WORLD,  "\n  Time for this analysis  = %.4g secs\n\n",solutionAnalysisTime);
        
        Stg_VecDestroy(&t2 );
        Stg_VecDestroy(&q );
            
    }
                
    if(bsscrp_self->mg) {
        //MG_inner_solver_pcmg_shutdown( pcInner );
    }

    Stg_VecDestroy(&t );

        
//      KSPLogDestroyMonitor( ksp_S );
        
    Stg_KSPDestroy(&ksp_S );
    //Stg_KSPDestroy(&ksp_inner );
    Stg_VecDestroy(&h_hat );
    Stg_MatDestroy(&S );

    /* Destroy nullspace vector if it exists. */
    if(nsp_vec)
        Stg_VecDestroy(&nsp_vec);
       
    //been_here = 1;
    been_here++;
    PetscFunctionReturn(0);
}
PetscErrorCode BSSCR_DRIVER_auglag( KSP ksp, Mat stokes_A, Vec stokes_x, Vec stokes_b, Mat approxS,
                                          MatStokesBlockScaling BA, PetscTruth sym, KSP_BSSCR * bsscrp_self )
{
    AugLagStokes_SLE *    stokesSLE = (AugLagStokes_SLE*)bsscrp_self->solver->st_sle;
    PetscTruth uzawastyle, KisJustK=PETSC_TRUE, restorek, change_A11rhspresolve;
    PetscTruth usePreviousGuess, useNormInfStoppingConditions, useNormInfMonitor, found, forcecorrection;
    PetscTruth change_backsolve, mg_active;
    PetscErrorCode ierr;
    //PetscInt monitor_index;
    PetscInt max_it,min_it;
    KSP ksp_inner, ksp_S, ksp_new_inner;
    PC pc_S, pcInner;
    Mat K,G,D,C, S, K2;// Korig;
    Vec u,p,f,f2=0,f3=0,h, h_hat,t;
    MGContext mgCtx;
    double mgSetupTime, scrSolveTime, a11SingleSolveTime, penaltyNumber;// hFactor;
    static int been_here = 0;  /* Ha Ha Ha !! */

    char name[PETSC_MAX_PATH_LEN];
    char matname[PETSC_MAX_PATH_LEN];
    char suffix[PETSC_MAX_PATH_LEN];
    char str[PETSC_MAX_PATH_LEN];
    PetscTruth flg, extractMats;
    PetscLogDouble flopsA,flopsB;

    /***************************************************************************************************************/
    /***************************************************************************************************************/
    //if( bsscrp_self->solver->st_sle->context->loadFromCheckPoint ){
    //    been_here=1;
    //}
    /* get sub matrix / vector objects */
    /* note that here, the matrix D should always exist. It is set up in  _StokesBlockKSPInterface_Solve in StokesBlockKSPInterface.c */
    /* now extract K,G etc from a MatNest object */
    MatNestGetSubMat( stokes_A, 0,0, &K );
    MatNestGetSubMat( stokes_A, 0,1, &G );
    MatNestGetSubMat( stokes_A, 1,0, &D );if(!D){ PetscPrintf( PETSC_COMM_WORLD, "D does not exist but should!!\n"); exit(1); }
    MatNestGetSubMat( stokes_A, 1,1, &C );  
    VecNestGetSubVec( stokes_x, 0, &u );
    VecNestGetSubVec( stokes_x, 1, &p );
    VecNestGetSubVec( stokes_b, 0, &f );
    VecNestGetSubVec( stokes_b, 1, &h );
    
    PetscPrintf( PETSC_COMM_WORLD,  "\n\n----------  AUGMENTED LAGRANGIAN K2 METHOD ---------\n\n" );
    PetscPrintf( PETSC_COMM_WORLD,      "----------- Penalty = %f\n\n", bsscrp_self->solver->penaltyNumber );
    sprintf(suffix,"%s","x");

    PetscOptionsGetString( PETSC_NULL, "-matsuffix", suffix, PETSC_MAX_PATH_LEN-1, &extractMats );

    flg=0;
    PetscOptionsGetString( PETSC_NULL, "-matdumpdir", name, PETSC_MAX_PATH_LEN-1, &flg );
    if(flg){
        sprintf(str,"%s/",name); sprintf(matname,"K%s",suffix);
        bsscr_dirwriteMat( K, matname,str, "Writing K matrix in al Solver");
        sprintf(str,"%s/",name); sprintf(matname,"G%s",suffix);
        bsscr_dirwriteMat( G, matname,str, "Writing G matrix in al Solver");
        sprintf(str,"%s/",name); sprintf(matname,"D%s",suffix);
        bsscr_dirwriteMat( D, matname,str, "Writing D matrix in al Solver");
        sprintf(str,"%s/",name); sprintf(matname,"f%s",suffix);
        bsscr_dirwriteVec( f, matname,str, "Writing f vector in al Solver");
        sprintf(str,"%s/",name); sprintf(matname,"h%s",suffix);
        bsscr_dirwriteVec( h, matname,str, "Writing h vector in al Solver");
        sprintf(str,"%s/",name); sprintf(matname,"Shat%s",suffix);
        bsscr_dirwriteMat( approxS, matname,str, "Writing Shat matrix in al Solver");
        if(C){
          sprintf(str,"%s/",name); sprintf(matname,"C%s",suffix);
          bsscr_dirwriteMat( C, matname,str, "Writing C matrix in al Solver");
        }
    }

    mg_active=PETSC_TRUE;
    PetscOptionsGetTruth( PETSC_NULL ,"-A11_mg_active", &mg_active, &found );
    bsscrp_self->solver->mg_active=mg_active;

    penaltyNumber = bsscrp_self->solver->penaltyNumber;
    //hFactor = stokesSLE->hFactor;
    /***************************************************************************************************************/
    /***************************************************************************************************************/
    /******  GET K2   ****************************************************************************************/
    if(penaltyNumber > 1e-10 && bsscrp_self->k2type){
        flg=0;
        PetscOptionsGetString( PETSC_NULL, "-matdumpdir", name, PETSC_MAX_PATH_LEN-1, &flg );
        if(flg){
            sprintf(str,"%s/",name);   sprintf(matname,"K2%s",suffix);
            bsscr_dirwriteMat( bsscrp_self->K2, matname,str, "Writing K2 matrix in al Solver");
        }
        K2=bsscrp_self->K2;
        scrSolveTime = MPI_Wtime();
        ierr=MatAXPY(K,penaltyNumber,K2,DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);/* Computes K = penaltyNumber*K2 + K */
        scrSolveTime =  MPI_Wtime() - scrSolveTime;
        PetscPrintf( PETSC_COMM_WORLD, "\n\t* K+p*K2 in time: %lf seconds\n\n", scrSolveTime);
        KisJustK=PETSC_FALSE;
        forcecorrection=PETSC_TRUE;
        PetscOptionsGetTruth( PETSC_NULL ,"-force_correction", &forcecorrection, &found );
        if(forcecorrection){
            if(bsscrp_self->f2 && forcecorrection){ 
                f2=bsscrp_self->f2;
                ierr=VecAXPY(f,penaltyNumber,f2);/*  f <- f +a*f2 */
            }else{
                switch (bsscrp_self->k2type) {
                case (K2_GG):
                {
                    VecDuplicate( u, &f3 );
                    MatMult( G, h, f3);   ierr=VecAXPY(f,penaltyNumber,f3);/*  f <- f +a*f2 */
                }
                break;
                case (K2_GMG):
                {
                    Mat M;
                    Vec Mdiag;
                    VecDuplicate( u, &f3 );
                    M = bsscrp_self->solver->mStiffMat->matrix;
                    MatGetVecs( M, &Mdiag, PETSC_NULL );
                    MatGetDiagonal( M, Mdiag );
                    VecReciprocal(Mdiag);
                    VecPointwiseMult(Mdiag,Mdiag,h);
                    MatMult( G, Mdiag, f3);   ierr=VecAXPY(f,penaltyNumber,f3);/*  f <- f +a*f2 */
                    Stg_VecDestroy(&Mdiag);
                }
                break;
                case (K2_DGMGD):
                {
                    Mat M;
                    Vec Mdiag;
                    VecDuplicate( u, &f3 );
                    M = bsscrp_self->solver->mStiffMat->matrix;
                    MatGetVecs( M, &Mdiag, PETSC_NULL );
                    MatGetDiagonal( M, Mdiag );
                    VecReciprocal(Mdiag);
                    VecPointwiseMult(Mdiag,Mdiag,h);
                    MatMult( G, Mdiag, f3);   ierr=VecAXPY(f,penaltyNumber,f3);/*  f <- f +a*f2 */
                    Stg_VecDestroy(&Mdiag);
                }
                break;
                case (K2_NULL):
                {
                    ;
                }
                break;
                case (K2_SLE):
                {
                    ;
                }
                break;
                }
            }
        }
    }

    /* Create Schur complement matrix */
    MatCreateSchurComplement(K,K,G,D,C, &S);
    MatSchurComplementGetKSP( S, &ksp_inner);
    KSPGetPC( ksp_inner, &pcInner );
    /***************************************************************************************************************/
    /***************************************************************************************************************/
    /*********    SET PREFIX FOR INNER/VELOCITY KSP    *************************************************************/
    KSPSetOptionsPrefix( ksp_inner, "A11_" );
    KSPSetFromOptions( ksp_inner );
    Stg_KSPSetOperators(ksp_inner, K, K, DIFFERENT_NONZERO_PATTERN);

    useNormInfStoppingConditions = PETSC_FALSE;
    PetscOptionsGetTruth( PETSC_NULL ,"-A11_use_norm_inf_stopping_condition", &useNormInfStoppingConditions, &found );
    if(useNormInfStoppingConditions) 
        BSSCR_KSPSetNormInfConvergenceTest( ksp_inner ); 

    useNormInfMonitor = PETSC_FALSE; 
    PetscOptionsGetTruth( PETSC_NULL, "-A11_ksp_norm_inf_monitor", &useNormInfMonitor, &found );
    if(useNormInfMonitor)  KSPMonitorSet( ksp_inner, BSSCR_KSPNormInfMonitor, PETSC_NULL, PETSC_NULL );

    useNormInfMonitor = PETSC_FALSE; 
    PetscOptionsGetTruth( PETSC_NULL, "-A11_ksp_norm_inf_to_norm_2_monitor", &useNormInfMonitor, &found );
    if(useNormInfMonitor)  KSPMonitorSet( ksp_inner, BSSCR_KSPNormInfToNorm2Monitor, PETSC_NULL, PETSC_NULL );
    /***************************************************************************************************************/
    /***************************************************************************************************************/
    /* If multigrid is enabled, set it now. */
    change_A11rhspresolve = PETSC_FALSE; 
    PetscOptionsGetTruth( PETSC_NULL, "-change_A11rhspresolve", &change_A11rhspresolve, &found );

    if(bsscrp_self->solver->mg_active && !change_A11rhspresolve) { mgSetupTime=setupMG( bsscrp_self, ksp_inner, pcInner, K, &mgCtx ); }
    /***************************************************************************************************************/
    /***************************************************************************************************************/
    /* create right hand side */
    if(change_A11rhspresolve){
      //Stg_KSPDestroy(&ksp_inner );
      KSPCreate(PETSC_COMM_WORLD, &ksp_new_inner);
      Stg_KSPSetOperators(ksp_new_inner, K, K, DIFFERENT_NONZERO_PATTERN);
      KSPSetOptionsPrefix(ksp_new_inner, "rhsA11_");
      MatSchurComplementSetKSP( S, ksp_new_inner );/* this call destroys the ksp_inner that is already set on S */
      ksp_inner=ksp_new_inner;
      KSPGetPC( ksp_inner, &pcInner );
      KSPSetFromOptions(ksp_inner); /* make sure we are setting up our solver how we want it */
    }
    MatGetVecs( S, PETSC_NULL, &h_hat );
    Vec f_tmp;
    /* It may be the case that the current velocity solution might not be bad guess for f_tmp? <-- maybe not */
    MatGetVecs( K, PETSC_NULL, &f_tmp );
    scrSolveTime = MPI_Wtime();
    KSPSolve(ksp_inner, f, f_tmp);
    scrSolveTime =  MPI_Wtime() - scrSolveTime;
    PetscPrintf( PETSC_COMM_WORLD, "\n\t*  KSPSolve for RHS setup Finished in time: %lf seconds\n\n", scrSolveTime);
    MatMult(D, f_tmp, h_hat);
    VecAYPX(h_hat, -1.0, h); /* Computes y = x + alpha y.  h_hat -> h - Gt*K^(-1)*f*/
    Stg_VecDestroy(&f_tmp);

    if(bsscrp_self->solver->mg_active && change_A11rhspresolve) {
      //Stg_KSPDestroy(&ksp_inner );
      KSPCreate(PETSC_COMM_WORLD, &ksp_new_inner);
      Stg_KSPSetOperators(ksp_new_inner, K, K, DIFFERENT_NONZERO_PATTERN);
      KSPSetOptionsPrefix( ksp_new_inner, "A11_" );
      MatSchurComplementSetKSP( S, ksp_new_inner );
      ksp_inner=ksp_new_inner;
      //MatSchurSetKSP( S, ksp_inner );
      KSPGetPC( ksp_inner, &pcInner );
      KSPSetFromOptions( ksp_inner );
      mgSetupTime=setupMG( bsscrp_self, ksp_inner, pcInner, K, &mgCtx ); 
    }
    /* create solver for S p = h_hat */
    KSPCreate( PETSC_COMM_WORLD, &ksp_S );
    KSPSetOptionsPrefix( ksp_S, "scr_");
    /* By default use the UW approxS Schur preconditioner -- same as the one used by the Uzawa solver */
    /* Note that if scaling is activated then the approxS matrix has been scaled already */
    /* so no need to rebuild in the case of scaling as we have been doing */
    if(!approxS){ PetscPrintf( PETSC_COMM_WORLD,  "WARNING approxS is NULL\n"); }
    Stg_KSPSetOperators( ksp_S, S, S, SAME_NONZERO_PATTERN );
    KSPSetType( ksp_S, "cg" );
    KSPGetPC( ksp_S, &pc_S );
    BSSCR_BSSCR_StokesCreatePCSchur2( K,G,D,C,approxS, pc_S, sym, bsscrp_self );

    flg=0;
    PetscOptionsGetString( PETSC_NULL, "-NN", name, PETSC_MAX_PATH_LEN-1, &flg );
    if(flg){
      Mat Smat, Pmat;                                                                                                 
      //MatStructure mstruct;  
      Stg_PCGetOperators( pc_S, &Smat, &Pmat, NULL );
      sprintf(str,"%s/",name); sprintf(matname,"Pmat%s",suffix);
      bsscr_dirwriteMat( Pmat, matname,str, "Writing Pmat matrix in al Solver");
    }
   
    uzawastyle=PETSC_FALSE;
    PetscOptionsGetTruth( PETSC_NULL, "-uzawa_style", &uzawastyle, &found );
    if(uzawastyle){
        /* now want to set up the ksp_S->pc to be of type ksp (gmres) by default to match Uzawa */
        KSP pc_ksp;
        KSPGetPC( ksp_S, &pc_S );
        PCSetType(pc_S,PCKSP);
        PCKSPGetKSP( pc_S, &pc_ksp);
        KSPSetType(pc_ksp, "gmres" );
        KSPSetOptionsPrefix( pc_ksp, "scrPCKSP_");
        KSPSetFromOptions( pc_ksp );
    }
    KSPSetFromOptions( ksp_S );
    /* Set specific monitor test */
    KSPGetTolerances( ksp_S, PETSC_NULL, PETSC_NULL, PETSC_NULL, &max_it );
    // Weirdness with petsc 3.2 here...look at it later
    //BSSCR_KSPLogSetMonitor( ksp_S, max_it, &monitor_index );

    /***************************************************************************************************************/
    /* Pressure / Velocity Solve */     
    /***************************************************************************************************************/
    PetscPrintf( PETSC_COMM_WORLD, "\t* Pressure / Velocity Solve \n");
    /***************************************************************************************************************/
    /***************************************************************************************************************/
    usePreviousGuess = PETSC_FALSE; 
    if(been_here)
        PetscOptionsGetTruth( PETSC_NULL, "-scr_use_previous_guess", &usePreviousGuess, &found );
    if(usePreviousGuess) {   /* Note this should actually look at checkpoint information */
        KSPSetInitialGuessNonzero( ksp_S, PETSC_TRUE ); }
    else {
        KSPSetInitialGuessNonzero( ksp_S, PETSC_FALSE ); }
    /***************************************************************************************************************/
    /***************************************************************************************************************/
    /*******     SET CONVERGENCE TESTS     *************************************************************************/
    useNormInfStoppingConditions = PETSC_FALSE;
    PetscOptionsGetTruth( PETSC_NULL ,"-scr_use_norm_inf_stopping_condition", &useNormInfStoppingConditions, &found );
    if(useNormInfStoppingConditions) 
        BSSCR_KSPSetNormInfConvergenceTest(ksp_S); 

    useNormInfMonitor = PETSC_FALSE; 
    PetscOptionsGetTruth( PETSC_NULL, "-scr_ksp_norm_inf_monitor", &useNormInfMonitor, &found );
    if(useNormInfMonitor) 
        KSPMonitorSet( ksp_S, BSSCR_KSPNormInfToNorm2Monitor, PETSC_NULL, PETSC_NULL );
    /***************************************************************************************************************/
    /***************************************************************************************************************/
    /*******   PRESSURE SOLVE   ************************************************************************************/
    PetscPrintf( PETSC_COMM_WORLD, "\t* KSPSolve( ksp_S, h_hat, p )\n");
    /* if h_hat needs to be fixed up ..take out any nullspace vectors here */
    /* we want to check that there is no "noise" in the null-space in the h vector */
    /* this causes problems when we are trying to solve a Jacobian system when the Residual is almost converged */
    if(bsscrp_self->check_pressureNS){
        bsscrp_self->buildPNS(ksp);/* build and set nullspace vectors on bsscr - which is on ksp (function pointer is set in KSPSetUp_BSSCR) */
    }

    PetscScalar hnorm, gnorm;
    MatNorm(G,NORM_INFINITY,&gnorm);
    VecNorm(h_hat, NORM_2, &hnorm);
    hnorm=hnorm/gnorm;

    if((hnorm < 1e-6) && (hnorm > 1e-20)){
        VecScale(h_hat,1.0/hnorm);
    }
    /* test to see if v or t are in nullspace of G and orthogonalize wrt h_hat if needed */
    KSPRemovePressureNullspace_BSSCR(ksp, h_hat);
    /* set convergence test to use min_it */
    found = PETSC_FALSE;
    min_it = 0;
    PetscOptionsGetInt( PETSC_NULL,"-scr_ksp_set_min_it_converge", &min_it, &found);
    if(found && min_it > 0){
        BSSCR_KSPSetConvergenceMinIts(ksp_S, min_it, bsscrp_self);
    }

    /** Pressure Solve **/
    PetscGetFlops(&flopsA);
    scrSolveTime = MPI_Wtime();
    KSPSolve( ksp_S, h_hat, p );
    scrSolveTime =  MPI_Wtime() - scrSolveTime;
    PetscGetFlops(&flopsB);
    PetscPrintf( PETSC_COMM_WORLD, "\n\t* KSPSolve( ksp_S, h_hat, p )  Solve Finished in time: %lf seconds\n\n", scrSolveTime);
    bsscrp_self->solver->stats.pressure_time=scrSolveTime;
    bsscrp_self->solver->stats.pressure_flops=(double)(flopsB-flopsA);

    /***************************************/
    if((hnorm < 1e-6) && (hnorm > 1e-20)){
        VecScale(h_hat,hnorm);
        VecScale(p,hnorm);
    }
    KSPRemovePressureNullspace_BSSCR(ksp, p);

    /***************************************************************************************************************/
    /***************************************************************************************************************/
    /* restore K and f for the Velocity back solve */
    found = PETSC_FALSE;
    restorek = PETSC_FALSE;
    PetscOptionsGetTruth( PETSC_NULL, "-restore_K", &restorek, &found);
    //PetscOptionsGetString( PETSC_NULL, "-restore_K", name, PETSC_MAX_PATH_LEN-1, &flg );
    if(penaltyNumber > 1e-10 && bsscrp_self->k2type){
        if(restorek){
            penaltyNumber = -penaltyNumber;
            if(f2) { ierr=VecAXPY(f,penaltyNumber,f2); }/*  f <- f +a*f2 */
            if(f3) { ierr=VecAXPY(f,penaltyNumber,f3); }/*  f <- f +a*f3 */
            ierr=MatAXPY(K,penaltyNumber,K2,DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);/* Computes K = penaltyNumber*K2 + K */
            //K=Korig;
            Stg_KSPSetOperators(ksp_inner, K, K, DIFFERENT_NONZERO_PATTERN);
            KisJustK=PETSC_TRUE;          
        }      
    }
    if(f3){ Stg_VecDestroy(&f3 ); } /* always destroy this local vector if was created */

    /* obtain solution for u */
    VecDuplicate( u, &t );   MatMult( G, p, t);  VecAYPX( t, -1.0, f ); /*** t <- -t + f   = f - G*p  ***/
    MatSchurComplementGetKSP( S, &ksp_inner );
    a11SingleSolveTime = MPI_Wtime();           /* ----------------------------------  Final V Solve */
    if(usePreviousGuess) KSPSetInitialGuessNonzero( ksp_inner, PETSC_TRUE );

    /***************************************************************************************************************/
    /***************************************************************************************************************/
    /*******   VELOCITY SOLVE   ************************************************************************************/
    /** Easier to just create a new KSP here if we want to do backsolve diffferently. (getting petsc errors now when switching from fgmres) */
    change_backsolve=PETSC_FALSE;
    PetscOptionsGetTruth( PETSC_NULL, "-change_backsolve", &change_backsolve, &found );
    if(change_backsolve){
      //Stg_KSPDestroy(&ksp_inner );
      KSPCreate(PETSC_COMM_WORLD, &ksp_new_inner);
      Stg_KSPSetOperators(ksp_new_inner, K, K, DIFFERENT_NONZERO_PATTERN);
      KSPSetOptionsPrefix(ksp_new_inner, "backsolveA11_");
      KSPSetFromOptions(ksp_new_inner); /* make sure we are setting up our solver how we want it */
      MatSchurComplementSetKSP( S, ksp_new_inner );/* need to give the Schur it's inner ksp back for when we destroy it at end */
      ksp_inner=ksp_new_inner;
    }

    PetscGetFlops(&flopsA);
    KSPSolve(ksp_inner, t, u);         /* Solve, then restore default tolerance and initial guess */
    PetscGetFlops(&flopsB);
    bsscrp_self->solver->stats.velocity_backsolve_flops=(double)(flopsB-flopsA);
    a11SingleSolveTime = MPI_Wtime() - a11SingleSolveTime;              /* ------------------ Final V Solve */
    bsscrp_self->solver->stats.velocity_backsolve_time=a11SingleSolveTime;

    flg=0;
    PetscOptionsGetString( PETSC_NULL, "-solutiondumpdir", name, PETSC_MAX_PATH_LEN-1, &flg );
    if(flg){
        sprintf(str,"%s/",name); sprintf(matname,"p%s",suffix);
        bsscr_dirwriteVec( p, matname,str, "Writing p vector in al Solver");
        sprintf(str,"%s/",name); sprintf(matname,"u%s",suffix);
        bsscr_dirwriteVec( u, matname,str, "Writing u vector in al Solver");
        sprintf(str,"%s/",name); sprintf(matname,"h_hat%s",suffix);
        bsscr_dirwriteVec( h_hat, matname,str, "Writing h_hat vector in al Solver");

    }

    found = PETSC_FALSE;
    restorek = PETSC_FALSE;
    PetscOptionsGetTruth( PETSC_NULL, "-restore_K_after_solve", &restorek, &found);
    if(penaltyNumber > 1e-10 && bsscrp_self->k2type){
        if(restorek){
            penaltyNumber = -penaltyNumber;
            ierr=MatAXPY(K,penaltyNumber,K2,DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);/* Computes K = penaltyNumber*K2 + K */
            KisJustK=PETSC_TRUE;          
        }      
    }
    /***************************************************************************************************************/
    /***************************************************************************************************************/
    /******     SOLUTION SUMMARY      ******************************************************************************/
    bsscr_summary(bsscrp_self,ksp_S,ksp_inner,K,K2,D,G,C,u,p,f,h,t,penaltyNumber,KisJustK, mgSetupTime, scrSolveTime, a11SingleSolveTime);
    //bsscr_summary(bsscrp_self,ksp_S,ksp_inner,K,Korig,K2,D,G,C,u,p,f,h,t,penaltyNumber,KisJustK, mgSetupTime, scrSolveTime, a11SingleSolveTime);
    /***************************************************************************************************************/
    /***************************************************************************************************************/
    Stg_VecDestroy(&t );
    Stg_KSPDestroy(&ksp_S );
    Stg_VecDestroy(&h_hat );
    Stg_MatDestroy(&S );//This will destroy ksp_inner: also.. pcInner == pc_MG and is destroyed when ksp_inner is 
    been_here = 1;
    PetscFunctionReturn(0);
}
Example #4
0
PetscErrorCode PCBDDCSubSchursSetUp(PCBDDCSubSchurs sub_schurs, Mat S, IS is_A_I, IS is_A_B, PetscInt ncc, IS is_cc[], PetscInt xadj[], PetscInt adjncy[], PetscInt nlayers)
{
  Mat                    A_II,A_IB,A_BI,A_BB;
  ISLocalToGlobalMapping BtoNmap,ItoNmap;
  PetscBT                touched;
  PetscInt               i,n_I,n_B,n_local,*local_numbering;
  PetscBool              is_sorted;
  PetscErrorCode         ierr;

  PetscFunctionBegin;
  ierr = ISSorted(is_A_I,&is_sorted);CHKERRQ(ierr);
  if (!is_sorted) {
    SETERRQ(PetscObjectComm((PetscObject)is_A_I),PETSC_ERR_PLIB,"IS for I dofs should be shorted");
  }
  ierr = ISSorted(is_A_B,&is_sorted);CHKERRQ(ierr);
  if (!is_sorted) {
    SETERRQ(PetscObjectComm((PetscObject)is_A_B),PETSC_ERR_PLIB,"IS for B dofs should be shorted");
  }

  /* get sizes */
  ierr = ISGetLocalSize(is_A_I,&n_I);CHKERRQ(ierr);
  ierr = ISGetLocalSize(is_A_B,&n_B);CHKERRQ(ierr);
  n_local = n_I+n_B;

  /* maps */
  ierr = ISLocalToGlobalMappingCreateIS(is_A_B,&BtoNmap);CHKERRQ(ierr);
  if (nlayers >= 0 && xadj != NULL && adjncy != NULL) { /* I problems have a different size of the original ones */
    ierr = ISLocalToGlobalMappingCreateIS(is_A_I,&ItoNmap);CHKERRQ(ierr);
    /* allocate some auxiliary space */
    ierr = PetscMalloc1(n_local,&local_numbering);CHKERRQ(ierr);
    ierr = PetscBTCreate(n_local,&touched);CHKERRQ(ierr);
  } else {
    ItoNmap = 0;
    local_numbering = 0;
    touched = 0;
  }

  /* get Schur complement matrices */
  ierr = MatSchurComplementGetSubMatrices(S,&A_II,NULL,&A_IB,&A_BI,&A_BB);CHKERRQ(ierr);

  /* allocate space for schur complements */
  ierr = PetscMalloc5(ncc,&sub_schurs->is_AEj_I,ncc,&sub_schurs->is_AEj_B,ncc,&sub_schurs->S_Ej,ncc,&sub_schurs->work1,ncc,&sub_schurs->work2);CHKERRQ(ierr);
  sub_schurs->n_subs = ncc;

  /* cycle on subsets and extract schur complements */
  for (i=0;i<sub_schurs->n_subs;i++) {
    Mat      AE_II,AE_IE,AE_EI,AE_EE;
    IS       is_I,is_subset_B;

    /* get IS for subsets in B numbering */
    ierr = ISDuplicate(is_cc[i],&sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
    ierr = ISSort(sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
    ierr = ISGlobalToLocalMappingApplyIS(BtoNmap,IS_GTOLM_DROP,sub_schurs->is_AEj_B[i],&is_subset_B);CHKERRQ(ierr);

    /* BB block on subset */
    ierr = MatGetSubMatrix(A_BB,is_subset_B,is_subset_B,MAT_INITIAL_MATRIX,&AE_EE);CHKERRQ(ierr);

    if (ItoNmap) { /* is ItoNmap has been computed, extracts only a part of I dofs */
      const PetscInt* idx_B;
      PetscInt        n_local_dofs,n_prev_added,j,layer,subset_size;

      /* all boundary dofs must be skipped when adding layers */
      ierr = PetscBTMemzero(n_local,touched);CHKERRQ(ierr);
      ierr = ISGetIndices(is_A_B,&idx_B);CHKERRQ(ierr);
      for (j=0;j<n_B;j++) {
        ierr = PetscBTSet(touched,idx_B[j]);CHKERRQ(ierr);
      }
      ierr = ISRestoreIndices(is_A_B,&idx_B);CHKERRQ(ierr);

      /* add next layers of dofs */
      ierr = ISGetLocalSize(is_cc[i],&subset_size);CHKERRQ(ierr);
      ierr = ISGetIndices(is_cc[i],&idx_B);CHKERRQ(ierr);
      ierr = PetscMemcpy(local_numbering,idx_B,subset_size*sizeof(PetscInt));CHKERRQ(ierr);
      ierr = ISRestoreIndices(is_cc[i],&idx_B);CHKERRQ(ierr);
      n_local_dofs = subset_size;
      n_prev_added = subset_size;
      for (layer=0;layer<nlayers;layer++) {
        PetscInt n_added;
        if (n_local_dofs == n_I+subset_size) break;
        if (n_local_dofs > n_I+subset_size) {
          SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Error querying layer %d. Out of bound access (%d > %d)",layer,n_local_dofs,n_I+subset_size);
        }
        ierr = PCBDDCAdjGetNextLayer_Private(local_numbering+n_local_dofs,n_prev_added,touched,xadj,adjncy,&n_added);CHKERRQ(ierr);
        n_prev_added = n_added;
        n_local_dofs += n_added;
        if (!n_added) break;
      }

      /* IS for I dofs in original numbering and in I numbering */
      ierr = ISCreateGeneral(PetscObjectComm((PetscObject)ItoNmap),n_local_dofs-subset_size,local_numbering+subset_size,PETSC_COPY_VALUES,&sub_schurs->is_AEj_I[i]);CHKERRQ(ierr);
      ierr = ISSort(sub_schurs->is_AEj_I[i]);CHKERRQ(ierr);
      ierr = ISGlobalToLocalMappingApplyIS(ItoNmap,IS_GTOLM_DROP,sub_schurs->is_AEj_I[i],&is_I);CHKERRQ(ierr);

      /* II block */
      ierr = MatGetSubMatrix(A_II,is_I,is_I,MAT_INITIAL_MATRIX,&AE_II);CHKERRQ(ierr);
    } else { /* in this case we can take references of already existing IS and matrices for I dofs */
      /* IS for I dofs in original numbering */
      ierr = PetscObjectReference((PetscObject)is_A_I);CHKERRQ(ierr);
      sub_schurs->is_AEj_I[i] = is_A_I;

      /* IS for I dofs in I numbering TODO: "first" argument of ISCreateStride is not general */
      ierr = ISCreateStride(PetscObjectComm((PetscObject)is_A_I),n_I,0,1,&is_I);CHKERRQ(ierr);

      /* II block is the same */
      ierr = PetscObjectReference((PetscObject)A_II);CHKERRQ(ierr);
      AE_II = A_II;
    }

    /* IE block */
    ierr = MatGetSubMatrix(A_IB,is_I,is_subset_B,MAT_INITIAL_MATRIX,&AE_IE);CHKERRQ(ierr);

    /* EI block */
    ierr = MatGetSubMatrix(A_BI,is_subset_B,is_I,MAT_INITIAL_MATRIX,&AE_EI);CHKERRQ(ierr);

    /* setup Schur complements on subset */
    ierr = MatCreateSchurComplement(AE_II,AE_II,AE_IE,AE_EI,AE_EE,&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
    ierr = MatGetVecs(sub_schurs->S_Ej[i],&sub_schurs->work1[i],&sub_schurs->work2[i]);CHKERRQ(ierr);
    if (AE_II == A_II) { /* we can reuse the same ksp */
      KSP ksp;
      ierr = MatSchurComplementGetKSP(S,&ksp);CHKERRQ(ierr);
      ierr = MatSchurComplementSetKSP(sub_schurs->S_Ej[i],ksp);CHKERRQ(ierr);
    } else { /* build new ksp object which inherits ksp and pc types from the original one */
      KSP      origksp,schurksp;
      PC       origpc,schurpc;
      KSPType  ksp_type;
      PCType   pc_type;
      PetscInt n_internal;

      ierr = MatSchurComplementGetKSP(S,&origksp);CHKERRQ(ierr);
      ierr = MatSchurComplementGetKSP(sub_schurs->S_Ej[i],&schurksp);CHKERRQ(ierr);
      ierr = KSPGetType(origksp,&ksp_type);CHKERRQ(ierr);
      ierr = KSPSetType(schurksp,ksp_type);CHKERRQ(ierr);
      ierr = KSPGetPC(schurksp,&schurpc);CHKERRQ(ierr);
      ierr = KSPGetPC(origksp,&origpc);CHKERRQ(ierr);
      ierr = PCGetType(origpc,&pc_type);CHKERRQ(ierr);
      ierr = PCSetType(schurpc,pc_type);CHKERRQ(ierr);
      ierr = ISGetSize(is_I,&n_internal);CHKERRQ(ierr);
      if (n_internal) { /* UMFPACK gives error with 0 sized problems */
        MatSolverPackage solver=NULL;
        ierr = PCFactorGetMatSolverPackage(origpc,(const MatSolverPackage*)&solver);CHKERRQ(ierr);
        if (solver) {
          ierr = PCFactorSetMatSolverPackage(schurpc,solver);CHKERRQ(ierr);
        }
      }
      ierr = KSPSetUp(schurksp);CHKERRQ(ierr);
    }
    /* free */
    ierr = MatDestroy(&AE_II);CHKERRQ(ierr);
    ierr = MatDestroy(&AE_EE);CHKERRQ(ierr);
    ierr = MatDestroy(&AE_IE);CHKERRQ(ierr);
    ierr = MatDestroy(&AE_EI);CHKERRQ(ierr);
    ierr = ISDestroy(&is_I);CHKERRQ(ierr);
    ierr = ISDestroy(&is_subset_B);CHKERRQ(ierr);
  }
  /* free */
  ierr = ISLocalToGlobalMappingDestroy(&ItoNmap);CHKERRQ(ierr);
  ierr = ISLocalToGlobalMappingDestroy(&BtoNmap);CHKERRQ(ierr);
  ierr = PetscFree(local_numbering);CHKERRQ(ierr);
  ierr = PetscBTDestroy(&touched);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}