void createMG(LocalData* data) {
assert(data != NULL);
int nlevels = 1;
PetscOptionsGetInt(PETSC_NULL, "-nlevels", &nlevels, PETSC_NULL);
int coarseSize = 1 + (((data->N) - 1)>>(nlevels - 1));
int rank;
MPI_Comm_rank((data->commAll), &rank);
if(!rank) {
std::cout<<"nlevels = "<<nlevels<<std::endl;
std::cout<<"coarseSize = "<<coarseSize<<std::endl;
}
DMMGCreate(PETSC_COMM_SELF, -nlevels, PETSC_NULL, &(data->mgObj));
DMMGSetOptionsPrefix(data->mgObj, "loc_");
DA da;
DACreate2d(PETSC_COMM_SELF, DA_NONPERIODIC, DA_STENCIL_BOX, coarseSize, coarseSize,
PETSC_DECIDE, PETSC_DECIDE, (data->dofsPerNode), 1, PETSC_NULL, PETSC_NULL, &da);
DMMGSetDM((data->mgObj), (DM)da);
DADestroy(da);
DMMGSetKSP((data->mgObj), PETSC_NULL, &computeMGmatrix);
PetscObjectIncrementTabLevel((PetscObject)(DMMGGetKSP(data->mgObj)), PETSC_NULL, 2);
}
/*
Setup for the custom preconditioner
*/
PetscErrorCode MyPCSetUp(PC pc)
{
AppCtx *app;
PetscErrorCode ierr;
DA da;
PetscFunctionBegin;
ierr = PCShellGetContext(pc,(void**)&app);
CHKERRQ(ierr);
/* create the linear solver for the Neutron diffusion */
ierr = DMMGCreate(app->comm,1,0,&app->fdmmg);
CHKERRQ(ierr);
ierr = DMMGSetOptionsPrefix(app->fdmmg,"phi_");
CHKERRQ(ierr);
ierr = DMMGSetUser(app->fdmmg,0,app);
CHKERRQ(ierr);
ierr = DACreate2d(app->comm,DA_NONPERIODIC,DA_STENCIL_STAR,app->nxv,app->nyvf,PETSC_DETERMINE,1,1,1,0,0,&da);
CHKERRQ(ierr);
ierr = DMMGSetDM(app->fdmmg,(DM)da);
CHKERRQ(ierr);
ierr = DMMGSetKSP(app->fdmmg,PETSC_NULL,MyFormMatrix);
CHKERRQ(ierr);
app->dx = DMMGGetRHS(app->fdmmg);
app->dy = DMMGGetx(app->fdmmg);
ierr = VecDuplicate(app->dy,&app->c);
CHKERRQ(ierr);
ierr = DADestroy(da);
CHKERRQ(ierr);
PetscFunctionReturn(0);
}
void InitializeDMMGSolver(State *BHD)
{
PC pc;
DMMG *dmmg;
int l;
DMMGCreate(PETSC_COMM_WORLD,2,PETSC_NULL,&dmmg);
DMMGSetDM(dmmg,(DM)BHD->da_dmmg);
DADestroy(BHD->da_dmmg);
for (l = 0; l < DMMGGetLevels(dmmg); l++)
{
DMMGSetUser(dmmg,l,(void*) BHD);
}
DMMGSetKSP(dmmg,ComputeRHSDMMG,InitializeLaplaceMatrix);
BHD->dmmg = dmmg;
}
