PetscErrorCode KSPBuildPressure_CB_Nullspace_BSSCR(KSP ksp)
{
KSP_BSSCR *bsscr = (KSP_BSSCR *)ksp->data;
FeEquationNumber *eq_num = bsscr->solver->st_sle->pSolnVec->feVariable->eqNum;
FeMesh *feMesh = bsscr->solver->st_sle->pSolnVec->feVariable->feMesh; /* is the pressure mesh */
unsigned ijk[3];
Vec t, v;
int numLocalNodes, globalNodeNumber, i, j, eq;
MatStokesBlockScaling BA = bsscr->BA;
PetscErrorCode ierr;
Mat Amat,Pmat, G;
MatStructure pflag;
PetscFunctionBegin;
/* get G matrix from Amat matrix operator on ksp */
ierr=Stg_PCGetOperators(ksp->pc,&Amat,&Pmat,&pflag);CHKERRQ(ierr);
MatNestGetSubMat( Amat, 0,1, &G );/* G should always exist */
/* now create Vecs t and v to match size of G: i.e. pressure */ /* NOTE: not using "h" vector from ksp->vec_rhs because this part of the block vector doesn't always exist */
MatGetVecs( G, &t, PETSC_NULL );/* t and v are destroyed in KSPDestroy_BSSCR */
MatGetVecs( G, &v, PETSC_NULL );/* t and v such that can do G*t */
numLocalNodes = Mesh_GetLocalSize( feMesh, MT_VERTEX); /* number of nodes on current proc not counting any shadow nodes */
for(j=0;j<numLocalNodes;j++){
i = globalNodeNumber = Mesh_DomainToGlobal( feMesh, MT_VERTEX, j);
RegularMeshUtils_Element_1DTo3D(feMesh, i, ijk);
eq = eq_num->destinationArray[j][0];/* get global equation number -- 2nd arg is always 0 because pressure has only one dof */
if(eq != -1){
if( (ijk[0]+ijk[1]+ijk[2])%2 ==0 ){
VecSetValue(t,eq,1.0,INSERT_VALUES);
}
else{
VecSetValue(v,eq,1.0,INSERT_VALUES); }}}
VecAssemblyBegin( t );
VecAssemblyEnd( t );
VecAssemblyBegin( v );
VecAssemblyEnd( v );
/* Scaling the null vectors here because it easier at the moment *//* maybe should do this in the original scaling function */
if( BA->scaling_exists == PETSC_TRUE ){
Vec R2;
/* Get the scalings out the block mat data */
VecNestGetSubVec( BA->Rz, 1, &R2 );
VecPointwiseDivide( t, t, R2); /* x <- x * 1/R2 */
VecPointwiseDivide( v, v, R2);
}
bsscr_writeVec( t, "t", "Writing t vector");
bsscr_writeVec( v, "v", "Writing v vector");
bsscr->t=t;
bsscr->v=v;
PetscFunctionReturn(0);
}
PetscErrorCode KSPRemovePressureNullspace_BSSCR(KSP ksp, Vec h_hat)
{
KSP_BSSCR *bsscr = (KSP_BSSCR *)ksp->data;
MatStokesBlockScaling BA = bsscr->BA;
PetscErrorCode ierr;
PetscScalar norm, a, a1, a2, hnorm, pnorm, gnorm;
Vec t2, t,v;
Mat Amat,Pmat, D;
MatStructure pflag;
double nstol = bsscr->nstol; /* set in KSPCreate_BSSCR */
PetscFunctionBegin;
t=bsscr->t;
v=bsscr->v;
/* get G matrix from Amat matrix operator on ksp */
ierr=Stg_PCGetOperators(ksp->pc,&Amat,&Pmat,&pflag);CHKERRQ(ierr);
//MatNestGetSubMat( Amat, 0,1, &G );/* G should always exist */
MatNestGetSubMat( Amat, 1,0, &D );/* D should always exist */
/* now create Vec t2 to match left hand size of G: i.e. velocity */
MatGetVecs( D, &t2, PETSC_NULL );
MatNorm(D,NORM_INFINITY,&gnorm); /* seems like not a bad estimate of the largest eigenvalue for this matrix */
if(t){/* assumes that v and t are initially set to PETSC_NULL (in KSPCreate_BSSCR ) */
MatMultTranspose( D, t, t2);
VecNorm(t2, NORM_2, &norm);
VecNorm(t, NORM_2, &a);
norm=norm/a;/* so we are using unit null vector */
if(norm < nstol*gnorm){/* then t in NS of G */
VecDot(t,h_hat, &a1);
VecDot(t,t, &a2);
a=-a1/a2;
VecAXPY(h_hat, a, t);
VecDot(t,h_hat, &a1);
PetscPrintf( PETSC_COMM_WORLD, "\n\t* Found t NS norm= %g : Dot = %g\n\n", norm, a1);
}
}
if(v){
MatMultTranspose( D, v, t2);
VecNorm(t2, NORM_2, &norm);
VecNorm(v, NORM_2, &a);
norm=norm/a;/* so we are using unit null vector */
if(norm < nstol*gnorm){/* then v in NS of G */
VecDot(v,h_hat, &a1);
VecDot(v,v, &a2);
a=-a1/a2;
VecAXPY(h_hat, a, v);
VecDot(v,h_hat, &a1);
PetscPrintf( PETSC_COMM_WORLD, "\n\t* Found v NS norm= %g : Dot = %g\n\n", norm, a1);
}
}
bsscr_writeVec( h_hat, "h", "Writing h_hat Vector in Solver");
Stg_VecDestroy(&t2);
PetscFunctionReturn(0);
}
PetscErrorCode KSPBuildPressure_Const_Nullspace_BSSCR(KSP ksp)
{
KSP_BSSCR *bsscr = (KSP_BSSCR *)ksp->data;
FeEquationNumber *eq_num = bsscr->solver->st_sle->pSolnVec->feVariable->eqNum;
FeMesh *feMesh = bsscr->solver->st_sle->pSolnVec->feVariable->feMesh; /* is the pressure mesh */
unsigned ijk[3];
Vec t;
int numLocalNodes, globalNodeNumber, i, eq;
MatStokesBlockScaling BA = bsscr->BA;
PetscErrorCode ierr;
Mat Amat,Pmat, G;
MatStructure pflag;
PetscFunctionBegin;
/* get G matrix from Amat matrix operator on ksp */
ierr=Stg_PCGetOperators(ksp->pc,&Amat,&Pmat,&pflag);CHKERRQ(ierr);
MatNestGetSubMat( Amat, 0,1, &G );/* G should always exist */
/* now create Vec t to match size of G: i.e. pressure */ /* NOTE: not using "h" vector from ksp->vec_rhs because this part of the block vector doesn't always exist */
MatGetVecs( G, &t, PETSC_NULL );/* t is destroyed in KSPDestroy_BSSCR */
VecSet(t, 1.0);
VecAssemblyBegin( t );
VecAssemblyEnd( t );
/* Scaling the null vectors here because it easier at the moment */
if( BA->scaling_exists == PETSC_TRUE ){
Vec R2;
/* Get the scalings out the block mat data */
VecNestGetSubVec( BA->Rz, 1, &R2 );
VecPointwiseDivide( t, t, R2); /* x <- x * 1/R2 */
}
bsscr_writeVec( t, "t", "Writing t vector");
bsscr->t=t;
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);
}
