C++ PCSetType函数代码示例

PetscErrorCode STSetFromOptions_Shell(ST st)
{
  PetscErrorCode ierr;
  PC             pc;
  PCType         pctype;
  KSPType        ksptype;

  PetscFunctionBegin;
  if (!st->ksp) { ierr = STGetKSP(st,&st->ksp);CHKERRQ(ierr); }
  ierr = KSPGetPC(st->ksp,&pc);CHKERRQ(ierr);
  ierr = KSPGetType(st->ksp,&ksptype);CHKERRQ(ierr);
  ierr = PCGetType(pc,&pctype);CHKERRQ(ierr);
  if (!pctype && !ksptype) {
    if (st->shift_matrix == ST_MATMODE_SHELL) {
      /* in shell mode use GMRES with Jacobi as the default */
      ierr = KSPSetType(st->ksp,KSPGMRES);CHKERRQ(ierr);
      ierr = PCSetType(pc,PCJACOBI);CHKERRQ(ierr);
    } else {
      /* use direct solver as default */
      ierr = KSPSetType(st->ksp,KSPPREONLY);CHKERRQ(ierr);
      ierr = PCSetType(pc,PCREDUNDANT);CHKERRQ(ierr);
    }
  }
  PetscFunctionReturn(0);
}

static PetscErrorCode PCBDDCScalingSetUp_Deluxe_Private(PC pc)
{
  PC_BDDC                *pcbddc=(PC_BDDC*)pc->data;
  PCBDDCDeluxeScaling    deluxe_ctx=pcbddc->deluxe_ctx;
  PCBDDCSubSchurs        sub_schurs = pcbddc->sub_schurs;
  PetscErrorCode         ierr;

  PetscFunctionBegin;
  if (!sub_schurs->n_subs) {
    PetscFunctionReturn(0);
  }

  /* Create work vectors for sequential part of deluxe */
  ierr = MatCreateVecs(sub_schurs->S_Ej_all,&deluxe_ctx->seq_work1,&deluxe_ctx->seq_work2);CHKERRQ(ierr);

  /* Compute deluxe sequential scatter */
  if (sub_schurs->reuse_mumps && !sub_schurs->is_dir) {
    PCBDDCReuseMumps reuse_mumps = sub_schurs->reuse_mumps;
    ierr = PetscObjectReference((PetscObject)reuse_mumps->correction_scatter_B);CHKERRQ(ierr);
    deluxe_ctx->seq_scctx = reuse_mumps->correction_scatter_B;
  } else {
    ierr = VecScatterCreate(pcbddc->work_scaling,sub_schurs->is_Ej_all,deluxe_ctx->seq_work1,NULL,&deluxe_ctx->seq_scctx);CHKERRQ(ierr);
  }

  /* Create Mat object for deluxe scaling */
  ierr = PetscObjectReference((PetscObject)sub_schurs->S_Ej_all);CHKERRQ(ierr);
  deluxe_ctx->seq_mat = sub_schurs->S_Ej_all;
  if (sub_schurs->sum_S_Ej_all) { /* if this matrix is present, then we need to create the KSP object to invert it */
    PC               pc_temp;
    MatSolverPackage solver=NULL;
    char             ksp_prefix[256];
    size_t           len;

    ierr = KSPCreate(PETSC_COMM_SELF,&deluxe_ctx->seq_ksp);CHKERRQ(ierr);
    ierr = KSPSetOperators(deluxe_ctx->seq_ksp,sub_schurs->sum_S_Ej_all,sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
    ierr = KSPSetType(deluxe_ctx->seq_ksp,KSPPREONLY);CHKERRQ(ierr);
    ierr = KSPGetPC(deluxe_ctx->seq_ksp,&pc_temp);CHKERRQ(ierr);
    ierr = PCSetType(pc_temp,PCLU);CHKERRQ(ierr);
    ierr = KSPGetPC(pcbddc->ksp_D,&pc_temp);CHKERRQ(ierr);
    ierr = PCFactorGetMatSolverPackage(pc_temp,(const MatSolverPackage*)&solver);CHKERRQ(ierr);
    if (solver) {
      PC     new_pc;
      PCType type;

      ierr = PCGetType(pc_temp,&type);CHKERRQ(ierr);
      ierr = KSPGetPC(deluxe_ctx->seq_ksp,&new_pc);CHKERRQ(ierr);
      ierr = PCSetType(new_pc,type);CHKERRQ(ierr);
      ierr = PCFactorSetMatSolverPackage(new_pc,solver);CHKERRQ(ierr);
    }
    ierr = PetscStrlen(((PetscObject)(pcbddc->ksp_D))->prefix,&len);CHKERRQ(ierr);
    len -= 10; /* remove "dirichlet_" */
    ierr = PetscStrncpy(ksp_prefix,((PetscObject)(pcbddc->ksp_D))->prefix,len+1);CHKERRQ(ierr);
    ierr = PetscStrcat(ksp_prefix,"deluxe_");CHKERRQ(ierr);
    ierr = KSPSetOptionsPrefix(deluxe_ctx->seq_ksp,ksp_prefix);CHKERRQ(ierr);
    ierr = KSPSetFromOptions(deluxe_ctx->seq_ksp);CHKERRQ(ierr);
    ierr = KSPSetUp(deluxe_ctx->seq_ksp);CHKERRQ(ierr);
  }
  PetscFunctionReturn(0);
}

MGSolver_PETScData* MultigridSolver_CreateCoarseSolver( MultigridSolver* self, Mat matrix ) {
	//MatrixSolver*	coarseSolver;
	MGSolver_PETScData* courseSolver;
	unsigned	nProcs;
	PC		pc;

	MPI_Comm_size( self->mgData->comm, (int*)&nProcs );

	/*
	coarseSolver = (MatrixSolver*)PETScMatrixSolver_New( "" );
	PETScMatrixSolver_SetKSPType( coarseSolver, 
				      PETScMatrixSolver_KSPType_PreOnly );
	if( nProcs == 1 ) {
		PETScMatrixSolver_SetPCType( coarseSolver, 
					     PETScMatrixSolver_PCType_LU );
	}
	else {
		PETScMatrixSolver_SetPCType( coarseSolver, 
					     PETScMatrixSolver_PCType_RedundantLU );
	}
	MatrixSolver_SetMatrix( coarseSolver, matrix );
	*/
	
	if( nProcs == 1 ){
	    KSPCreate( MPI_COMM_WORLD, &courseSolver->ksp );
	    KSPSetType( courseSolver->ksp, KSPPREONLY );
	    KSPGetPC( courseSolver->ksp, &pc );
	    PCSetType( pc, PCLU );
	}
	else {
		PCSetType( pc, PCREDUNDANT );
		#if ((PETSC_VERSION_MAJOR>=3) && (PETSC_VERSION_MINOR>=2) )
		PCCreate( MPI_COMM_WORLD, &pc);
		PCRedundantGetKSP( pc, &courseSolver->ksp );
		#else
		KSPCreate( MPI_COMM_WORLD, &courseSolver->ksp );
		KSPSetType( courseSolver->ksp, KSPPREONLY );
		KSPGetPC( courseSolver->ksp, &pc );
		PCRedundantGetPC( pc, &pc );
                #endif
		PCSetType( pc, PCLU );
	}
        if( courseSolver->matrix != PETSC_NULL ){
	    Stg_MatDestroy(&courseSolver->matrix );}

	courseSolver->matrix = matrix;
	Stg_KSPSetOperators( courseSolver->ksp, matrix, matrix, DIFFERENT_NONZERO_PATTERN );

	return courseSolver;
}

static PetscErrorCode  PCRedundantGetKSP_Redundant(PC pc,KSP *innerksp)
{
  PetscErrorCode ierr;
  PC_Redundant   *red = (PC_Redundant*)pc->data;
  MPI_Comm       comm,subcomm;
  const char     *prefix;

  PetscFunctionBegin;
  if (!red->psubcomm) {
    ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
    ierr = PetscSubcommCreate(comm,&red->psubcomm);CHKERRQ(ierr);
    ierr = PetscSubcommSetNumber(red->psubcomm,red->nsubcomm);CHKERRQ(ierr);
    ierr = PetscSubcommSetType(red->psubcomm,PETSC_SUBCOMM_INTERLACED);CHKERRQ(ierr);
    ierr = PetscLogObjectMemory((PetscObject)pc,sizeof(PetscSubcomm));CHKERRQ(ierr);

    /* create a new PC that processors in each subcomm have copy of */
    subcomm = PetscSubcommChild(red->psubcomm);

    ierr = KSPCreate(subcomm,&red->ksp);CHKERRQ(ierr);
    ierr = KSPSetErrorIfNotConverged(red->ksp,pc->erroriffailure);CHKERRQ(ierr);
    ierr = PetscObjectIncrementTabLevel((PetscObject)red->ksp,(PetscObject)pc,1);CHKERRQ(ierr);
    ierr = PetscLogObjectParent((PetscObject)pc,(PetscObject)red->ksp);CHKERRQ(ierr);
    ierr = KSPSetType(red->ksp,KSPPREONLY);CHKERRQ(ierr);
    ierr = KSPGetPC(red->ksp,&red->pc);CHKERRQ(ierr);
    ierr = PCSetType(red->pc,PCLU);CHKERRQ(ierr);

    ierr = PCGetOptionsPrefix(pc,&prefix);CHKERRQ(ierr);
    ierr = KSPSetOptionsPrefix(red->ksp,prefix);CHKERRQ(ierr);
    ierr = KSPAppendOptionsPrefix(red->ksp,"redundant_");CHKERRQ(ierr);
  }
  *innerksp = red->ksp;
  PetscFunctionReturn(0);
}

END_TEST

START_TEST( Generate2DLapacian_test )
{
  PetscErrorCode ierr;
  PetscInt d = 50, len = d*d;
  Mat m;
  PetscViewer view;
  Generate2DLapacian( d, d, &m);
  
  PetscViewerASCIIOpen(PETSC_COMM_SELF, "mat.dat", &view);
  MatView(m, view);
  
  KSP ksp;
  PC pc;
  ierr = KSPCreate(PETSC_COMM_SELF, &ksp); CHKERRQ(ierr);
  KSPSetType(ksp, KSPPREONLY);
  KSPGetPC(ksp, &pc);
  PCSetType(pc, PCCHOLESKY);
  KSPSetOperators(ksp, m, m, SAME_PRECONDITIONER);
  Vec v, s;
  VecCreateSeq(PETSC_COMM_SELF,len,&v);
  VecDuplicate(v, &s);
  VecSet(v, 1);
  ierr = KSPSolve(ksp, v, s); CHKERRQ(ierr);
  
}

PetscErrorCode StokesSetupPC(Stokes *s, KSP ksp)
{
  KSP            *subksp;
  PC             pc, pc1;
  PetscInt       n = 1;
  PetscErrorCode ierr;

  PetscFunctionBeginUser;
  ierr = KSPGetPC(ksp, &pc);CHKERRQ(ierr);
  ierr = PCFieldSplitSetIS(pc, "0", s->isg[0]);CHKERRQ(ierr);
  ierr = PCFieldSplitSetIS(pc, "1", s->isg[1]);CHKERRQ(ierr);
  if (s->userPC) {
    ierr = PCFieldSplitSetSchurPre(pc, PC_FIELDSPLIT_SCHUR_PRE_USER, s->myS);CHKERRQ(ierr);
  }
  if (s->userKSP) {
    ierr = PCSetUp(pc);CHKERRQ(ierr);
    ierr = PCFieldSplitGetSubKSP(pc, &n, &subksp);CHKERRQ(ierr);
    ierr = KSPSetOperators(subksp[1], s->myS, s->myS);CHKERRQ(ierr);
   
    ierr = KSPGetPC(subksp[1], &pc1);CHKERRQ(ierr);
    ierr = PCSetUp(pc1);CHKERRQ(ierr);
    ierr = PCSetType(pc1,PCGAMG);CHKERRQ(ierr);
    ierr = PetscFree(subksp);CHKERRQ(ierr);
  }
  PetscFunctionReturn(0);
}

    void MGinit( const MgSmootherType &mg_smoother_type, const unsigned &levelMax ){

      KSPCreate(PETSC_COMM_WORLD,&_ksp);

      KSPGetPC(_ksp,&_pc);
      PCSetType(_pc,PCMG);
      PCMGSetLevels(_pc,levelMax,NULL);

      if( mg_smoother_type == FULL ){
        PCMGSetType(_pc, PC_MG_FULL);
      }
      else if( mg_smoother_type == MULTIPLICATIVE ){
        PCMGSetType(_pc, PC_MG_MULTIPLICATIVE);
      }
      else if( mg_smoother_type == ADDITIVE ){
        PCMGSetType(_pc, PC_MG_ADDITIVE);
      }
      else if( mg_smoother_type == KASKADE ){
        PCMGSetType(_pc, PC_MG_KASKADE);
      }
      else{
        std::cout <<"Wrong mg_type for PETSCsolve()"<<std::endl;
        abort();
      }
    };

MGSolver_PETScData* MultigridSolver_CreateSmoother( MultigridSolver* self, Mat matrix ) {
	//MatrixSolver*	smoother;
	MGSolver_PETScData* smoother = malloc( sizeof( MGSolver_PETScData ) );
	//unsigned	nBlocks;
	//KSP*		ksps;
	PC		pc;
	//PetscErrorCode	ec;

	/*
	smoother = (MatrixSolver*)PETScMatrixSolver_New( "" );
	PETScMatrixSolver_SetKSPType( smoother, 
				      PETScMatrixSolver_KSPType_Richardson );
	PETScMatrixSolver_SetPCType( smoother, 
				     PETScMatrixSolver_PCType_SOR );
	MatrixSolver_SetMatrix( smoother, matrix );
	*/
	KSPCreate( MPI_COMM_WORLD, &smoother->ksp );
	KSPSetType( smoother->ksp, KSPRICHARDSON );
	KSPGetPC( smoother->ksp, &pc );
	PCSetType( pc, PCSOR );
	if( smoother->matrix != PETSC_NULL )
		Stg_MatDestroy(&smoother->matrix );
	smoother->matrix = matrix;
	Stg_KSPSetOperators( smoother->ksp, matrix, matrix, DIFFERENT_NONZERO_PATTERN );

	return smoother;
}

MGSolver_PETScData* MultigridSolver_CreateOuterSolver( MultigridSolver* self, Mat matrix ) {
	//MatrixSolver*	outerSolver;
	MGSolver_PETScData* 	outerSolver = malloc( sizeof(MGSolver_PETScData) );
	PC			pc;

	/*
	outerSolver = (MatrixSolver*)PETScMatrixSolver_New( "" );
	PETScMatrixSolver_SetKSPType( outerSolver, PETScMatrixSolver_KSPType_Richardson );
	PETScMatrixSolver_SetPCType( outerSolver, PETScMatrixSolver_PCType_SOR );
	PETScMatrixSolver_SetMatrix( outerSolver, matrix );
	PETScMatrixSolver_SetMaxIterations( outerSolver, 3 );
	PETScMatrixSolver_SetUseInitialSolution( outerSolver, True );
	PETScMatrixSolver_SetNormType( outerSolver, PETScMatrixSolver_NormType_Preconditioned );
	*/
	KSPCreate( MPI_COMM_WORLD, &outerSolver->ksp );
	KSPSetType( outerSolver->ksp, KSPRICHARDSON );
	KSPGetPC( outerSolver->ksp, &pc );
	PCSetType( pc, PCSOR );
	if( outerSolver->matrix != PETSC_NULL )
		Stg_MatDestroy(&outerSolver->matrix );
	outerSolver->matrix = matrix;
	Stg_KSPSetOperators( outerSolver->ksp, matrix, matrix, DIFFERENT_NONZERO_PATTERN );
	KSPSetTolerances( outerSolver->ksp, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT, (PetscInt)3 );
	KSPSetInitialGuessNonzero( outerSolver->ksp, (PetscTruth)True );
	KSPSetNormType( outerSolver->ksp, MultigridSolver_NormType_Preconditioned );

	return outerSolver;
}

int main(int argc,char **args)
{
    PC             pc;
    PetscErrorCode ierr;
    PetscInt       n = 5;
    Mat            mat;

    ierr = PetscInitialize(&argc,&args,(char*)0,help);
    if (ierr) return ierr;
    ierr = PCCreate(PETSC_COMM_WORLD,&pc);
    CHKERRQ(ierr);
    ierr = PCSetType(pc,PCNONE);
    CHKERRQ(ierr);

    /* Vector and matrix must be set before calling PCSetUp */
    ierr = MatCreateSeqAIJ(PETSC_COMM_SELF,n,n,3,NULL,&mat);
    CHKERRQ(ierr);
    ierr = MatAssemblyBegin(mat,MAT_FINAL_ASSEMBLY);
    CHKERRQ(ierr);
    ierr = MatAssemblyEnd(mat,MAT_FINAL_ASSEMBLY);
    CHKERRQ(ierr);
    ierr = PCSetOperators(pc,mat,mat);
    CHKERRQ(ierr);
    ierr = PCSetUp(pc);
    CHKERRQ(ierr);
    ierr = MatDestroy(&mat);
    CHKERRQ(ierr);
    ierr = PCDestroy(&pc);
    CHKERRQ(ierr);
    ierr = PetscFinalize();
    return ierr;
}

PetscErrorCode SolvePressure(UserContext *uc)
{
  PetscErrorCode ierr;
  
  PetscFunctionBegin;
  PetscLogEventBegin(EVENT_SolvePressure,0,0,0,0);

  ierr = KSPCreate(PETSC_COMM_WORLD, &uc->ksp); CHKERRQ(ierr);
  ierr = KSPSetType(uc->ksp,KSPCG); CHKERRQ(ierr);
  ierr = KSPSetOperators(uc->ksp,uc->A,uc->A,SAME_NONZERO_PATTERN); CHKERRQ(ierr);
  ierr = KSPSetFromOptions(uc->ksp); CHKERRQ(ierr);
  ierr = KSPSetTolerances(uc->ksp, 0.000001, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT); CHKERRQ(ierr);
  
  ierr = KSPSetType( uc->ksp, KSPPREONLY); CHKERRQ(ierr);
  PC pc;
  ierr = KSPGetPC(uc->ksp, &pc); CHKERRQ(ierr);
  ierr = PCSetType(pc, PCLU); CHKERRQ(ierr);
  
  ierr = KSPSolve(uc->ksp,uc->b,uc->p);CHKERRQ(ierr);
  
  KSPConvergedReason reason;
  KSPGetConvergedReason(uc->ksp,&reason);
  PetscPrintf(PETSC_COMM_WORLD,"Pressure KSPConvergedReason: %D\n", reason);
  // if( reason < 0 )    SETERRQ(PETSC_ERR_CONV_FAILED, "Exiting: Failed to converge\n");
  
  PetscLogEventEnd(EVENT_SolvePressure,0,0,0,0);
  PetscFunctionReturn(0);
}

void PETSc::Solve_LSQR(void)
{
        
  //start_clock("Before Assemble matrix and vector");
	ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
  	ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
  	
  	ierr = VecAssemblyBegin(x);
  	ierr = VecAssemblyEnd(x);
  	
  	ierr = VecAssemblyBegin(b);
  	ierr = VecAssemblyEnd(b);
	//stop_clock("After Assembly matrix and vector");


        KSPSetOperators(ksp,A,A,DIFFERENT_NONZERO_PATTERN);
	KSPSetType(ksp,KSPLSQR);

	KSPGetPC(ksp, &pc);
	PCSetType(pc, PCNONE);

        KSPSetFromOptions(ksp);
        KSPSetUp(ksp);

	//start_clock("Before KSPSolve");
        KSPSolve(ksp,b,x);
	//	stop_clock("After KSPSolve");

}

void createOuterPC(OuterContext* ctx) {
  PCCreate(((ctx->data)->commAll), &(ctx->outerPC));
  PCSetType(ctx->outerPC, PCSHELL);
  PCShellSetName(ctx->outerPC, "RSD");
  PCShellSetContext(ctx->outerPC, ctx);
  PCShellSetApply(ctx->outerPC, &outerPCapply);
}

/*!
  \brief KSP and PC type

 KSPRICHARDSON "richardson"
 KSPCHEBYCHEV  "chebychev"
 KSPCG         "cg"
 KSPCGNE       "cgne"
 KSPNASH       "nash"
 KSPSTCG       "stcg"
 KSPGLTR       "gltr"
 KSPGMRES      "gmres"
 KSPFGMRES     "fgmres" 
 KSPLGMRES     "lgmres"
 KSPDGMRES     "dgmres"
 KSPTCQMR      "tcqmr"
 KSPBCGS       "bcgs"
 KSPIBCGS        "ibcgs"
 KSPBCGSL        "bcgsl"
 KSPCGS        "cgs"
 KSPTFQMR      "tfqmr"
 KSPCR         "cr"
 KSPLSQR       "lsqr"
 KSPPREONLY    "preonly"
 KSPQCG        "qcg"
 KSPBICG       "bicg"
 KSPMINRES     "minres"
 KSPSYMMLQ     "symmlq"
 KSPLCD        "lcd"
 KSPPYTHON     "python"
 KSPBROYDEN    "broyden"
 KSPGCR        "gcr"
 KSPNGMRES     "ngmres"
 KSPSPECEST    "specest"

 PCNONE            "none"
 PCJACOBI          "jacobi"
 PCSOR             "sor"
 PCLU              "lu"
 PCSHELL           "shell"
 PCBJACOBI         "bjacobi"
 PCMG              "mg"
 PCEISENSTAT       "eisenstat"
 PCILU             "ilu"
 PCICC             "icc"
 PCASM             "asm"
 PCGASM            "gasm"
 PCKSP             "ksp"
 PCCOMPOSITE       "composite"
 PCREDUNDANT       "redundant"
 PCSPAI            "spai"
 PCNN              "nn"
 PCCHOLESKY        "cholesky"
 PCPBJACOBI        "pbjacobi"
 PCMAT             "mat"
 PCHYPRE           "hypre"
 PCPARMS           "parms"
 PCFIELDSPLIT      "fieldsplit"
 PCTFS             "tfs"
 PCML              "ml"
 PCPROMETHEUS      "prometheus"
 PCGALERKIN        "galerkin"
 PCEXOTIC          "exotic"
 PCHMPI            "hmpi"
 PCSUPPORTGRAPH    "supportgraph"
 PCASA             "asa"
 PCCP              "cp"
 PCBFBT            "bfbt"
 PCLSC             "lsc"
 PCPYTHON          "python"
 PCPFMG            "pfmg"
 PCSYSPFMG         "syspfmg"
 PCREDISTRIBUTE    "redistribute"
 PCSACUSP          "sacusp"
 PCSACUSPPOLY      "sacusppoly"
 PCBICGSTABCUSP    "bicgstabcusp"
 PCSVD             "svd"
 PCAINVCUSP        "ainvcusp"
 PCGAMG            "gamg"

*/
void PETScLinearSolver::Config(const PetscReal tol, const PetscInt maxits, const KSPType lsol,
                               const PCType prec_type, const std::string &prefix)
{
   ltolerance = tol;
   sol_type = lsol;
   pc_type = prec_type; 

   KSPCreate(PETSC_COMM_WORLD,&lsolver);

#if (PETSC_VERSION_MAJOR == 3) && (PETSC_VERSION_MINOR > 4)
   KSPSetOperators(lsolver, A, A);
#else
   KSPSetOperators(lsolver, A, A, DIFFERENT_NONZERO_PATTERN);
#endif

   KSPSetType(lsolver,lsol);

   KSPGetPC(lsolver, &prec);
   PCSetType(prec, prec_type); //  PCJACOBI); //PCNONE);
   KSPSetTolerances(lsolver,ltolerance, PETSC_DEFAULT, PETSC_DEFAULT, maxits);
//.........这里部分代码省略.........

/*@C
   TSMonitorSPEigCtxCreate - Creates a context for use with TS to monitor the eigenvalues of the linearized operator

   Collective on TS

   Input Parameters:
+  host - the X display to open, or null for the local machine
.  label - the title to put in the title bar
.  x, y - the screen coordinates of the upper left coordinate of the window
.  m, n - the screen width and height in pixels
-  howoften - if positive then determines the frequency of the plotting, if -1 then only at the final time

   Output Parameter:
.  ctx - the context

   Options Database Key:
.  -ts_monitor_sp_eig - plot egienvalues of linearized right hand side

   Notes:
   Use TSMonitorSPEigCtxDestroy() to destroy.

   Currently only works if the Jacobian is provided explicitly.

   Currently only works for ODEs u_t - F(t,u) = 0; that is with no mass matrix.

   Level: intermediate

.keywords: TS, monitor, line graph, residual, seealso

.seealso: TSMonitorSPEigTimeStep(), TSMonitorSet(), TSMonitorLGSolution(), TSMonitorLGError()

@*/
PetscErrorCode  TSMonitorSPEigCtxCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscInt howoften,TSMonitorSPEigCtx *ctx)
{
  PetscDraw      win;
  PetscErrorCode ierr;
  PC             pc;

  PetscFunctionBegin;
  ierr = PetscNew(ctx);CHKERRQ(ierr);
  ierr = PetscRandomCreate(comm,&(*ctx)->rand);CHKERRQ(ierr);
  ierr = PetscRandomSetFromOptions((*ctx)->rand);CHKERRQ(ierr);
  ierr = PetscDrawCreate(comm,host,label,x,y,m,n,&win);CHKERRQ(ierr);
  ierr = PetscDrawSetFromOptions(win);CHKERRQ(ierr);
  ierr = PetscDrawSPCreate(win,1,&(*ctx)->drawsp);CHKERRQ(ierr);
  ierr = KSPCreate(comm,&(*ctx)->ksp);CHKERRQ(ierr);
  ierr = KSPSetOptionsPrefix((*ctx)->ksp,"ts_monitor_sp_eig_");CHKERRQ(ierr); /* this is wrong, used use also prefix from the TS */
  ierr = KSPSetType((*ctx)->ksp,KSPGMRES);CHKERRQ(ierr);
  ierr = KSPGMRESSetRestart((*ctx)->ksp,200);CHKERRQ(ierr);
  ierr = KSPSetTolerances((*ctx)->ksp,1.e-10,PETSC_DEFAULT,PETSC_DEFAULT,200);CHKERRQ(ierr);
  ierr = KSPSetComputeSingularValues((*ctx)->ksp,PETSC_TRUE);CHKERRQ(ierr);
  ierr = KSPSetFromOptions((*ctx)->ksp);CHKERRQ(ierr);
  ierr = KSPGetPC((*ctx)->ksp,&pc);CHKERRQ(ierr);
  ierr = PCSetType(pc,PCNONE);CHKERRQ(ierr);

  (*ctx)->howoften          = howoften;
  (*ctx)->computeexplicitly = PETSC_FALSE;

  ierr = PetscOptionsGetBool(NULL,"-ts_monitor_sp_eig_explicitly",&(*ctx)->computeexplicitly,NULL);CHKERRQ(ierr);

  (*ctx)->comm = comm;
  (*ctx)->xmin = -2.1;
  (*ctx)->xmax = 1.1;
  (*ctx)->ymin = -1.1;
  (*ctx)->ymax = 1.1;
  PetscFunctionReturn(0);
}