Example #1
0
int main(int argc,char **argv)
{
  PetscErrorCode ierr;
  KSP            ksp;
  DM             da,shell;
  PetscInt       levels;

  PetscInitialize(&argc,&argv,(char*)0,help);

  ierr = KSPCreate(PETSC_COMM_WORLD,&ksp);CHKERRQ(ierr);
  ierr = DMDACreate1d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,-129,1,1,0,&da);CHKERRQ(ierr);
  ierr = MyDMShellCreate(PETSC_COMM_WORLD,da,&shell);CHKERRQ(ierr);
  /* these two lines are not needed but allow PCMG to automatically know how many multigrid levels the user wants */
  ierr = DMGetRefineLevel(da,&levels);CHKERRQ(ierr);
  ierr = DMSetRefineLevel(shell,levels);CHKERRQ(ierr);

  ierr = KSPSetDM(ksp,shell);CHKERRQ(ierr);
  ierr = KSPSetComputeRHS(ksp,ComputeRHS,NULL);CHKERRQ(ierr);
  ierr = KSPSetComputeOperators(ksp,ComputeMatrix,NULL);CHKERRQ(ierr);
  ierr = KSPSetFromOptions(ksp);CHKERRQ(ierr);
  ierr = KSPSolve(ksp,NULL,NULL);CHKERRQ(ierr);

  ierr = KSPDestroy(&ksp);CHKERRQ(ierr);
  ierr = DMDestroy(&shell);CHKERRQ(ierr);
  ierr = DMDestroy(&da);CHKERRQ(ierr);
  ierr = PetscFinalize();

  return 0;
}
Example #2
0
/*@
   DMDAGetReducedDMDA - Gets the DMDA with the same layout but with fewer or more fields

   Collective on DMDA

   Input Parameters:
+  da - the distributed array
-  nfields - number of fields in new DMDA

   Output Parameter:
.  nda - the new DMDA

  Level: intermediate

.keywords: distributed array, get, corners, nodes, local indices, coordinates

.seealso: DMDAGetGhostCorners(), DMSetCoordinates(), DMDASetUniformCoordinates(), DMGetCoordinates(), DMDAGetGhostedCoordinates()
@*/
PetscErrorCode  DMDAGetReducedDMDA(DM da,PetscInt nfields,DM *nda)
{
  PetscErrorCode   ierr;
  DM_DA            *dd = (DM_DA*)da->data;
  PetscInt         s,m,n,p,M,N,P,dim,Mo,No,Po;
  const PetscInt   *lx,*ly,*lz;
  DMBoundaryType   bx,by,bz;
  DMDAStencilType  stencil_type;
  PetscInt         ox,oy,oz;
  PetscInt         cl,rl;

  PetscFunctionBegin;
  dim = da->dim;
  M   = dd->M;
  N   = dd->N;
  P   = dd->P;
  m   = dd->m;
  n   = dd->n;
  p   = dd->p;
  s   = dd->s;
  bx  = dd->bx;
  by  = dd->by;
  bz  = dd->bz;

  stencil_type = dd->stencil_type;

  ierr = DMDAGetOwnershipRanges(da,&lx,&ly,&lz);CHKERRQ(ierr);
  if (dim == 1) {
    ierr = DMDACreate1d(PetscObjectComm((PetscObject)da),bx,M,nfields,s,dd->lx,nda);CHKERRQ(ierr);
  } else if (dim == 2) {
    ierr = DMDACreate2d(PetscObjectComm((PetscObject)da),bx,by,stencil_type,M,N,m,n,nfields,s,lx,ly,nda);CHKERRQ(ierr);
  } else if (dim == 3) {
    ierr = DMDACreate3d(PetscObjectComm((PetscObject)da),bx,by,bz,stencil_type,M,N,P,m,n,p,nfields,s,lx,ly,lz,nda);CHKERRQ(ierr);
  }
  ierr = DMSetUp(*nda);CHKERRQ(ierr);
  if (da->coordinates) {
    ierr = PetscObjectReference((PetscObject)da->coordinates);CHKERRQ(ierr);
    (*nda)->coordinates = da->coordinates;
  }

  /* allow for getting a reduced DA corresponding to a domain decomposition */
  ierr = DMDAGetOffset(da,&ox,&oy,&oz,&Mo,&No,&Po);CHKERRQ(ierr);
  ierr = DMDASetOffset(*nda,ox,oy,oz,Mo,No,Po);CHKERRQ(ierr);

  /* allow for getting a reduced DA corresponding to a coarsened DA */
  ierr = DMGetCoarsenLevel(da,&cl);CHKERRQ(ierr);
  ierr = DMGetRefineLevel(da,&rl);CHKERRQ(ierr);

  (*nda)->levelup   = rl;
  (*nda)->leveldown = cl;
  PetscFunctionReturn(0);
}
Example #3
0
File: mg.c Project: ziolai/petsc
PetscErrorCode PCSetUp_MG(PC pc)
{
  PC_MG          *mg        = (PC_MG*)pc->data;
  PC_MG_Levels   **mglevels = mg->levels;
  PetscErrorCode ierr;
  PetscInt       i,n = mglevels[0]->levels;
  PC             cpc;
  PetscBool      dump = PETSC_FALSE,opsset,use_amat,missinginterpolate = PETSC_FALSE;
  Mat            dA,dB;
  Vec            tvec;
  DM             *dms;
  PetscViewer    viewer = 0;

  PetscFunctionBegin;
  /* FIX: Move this to PCSetFromOptions_MG? */
  if (mg->usedmfornumberoflevels) {
    PetscInt levels;
    ierr = DMGetRefineLevel(pc->dm,&levels);CHKERRQ(ierr);
    levels++;
    if (levels > n) { /* the problem is now being solved on a finer grid */
      ierr     = PCMGSetLevels(pc,levels,NULL);CHKERRQ(ierr);
      n        = levels;
      ierr     = PCSetFromOptions(pc);CHKERRQ(ierr); /* it is bad to call this here, but otherwise will never be called for the new hierarchy */
      mglevels =  mg->levels;
    }
  }
  ierr = KSPGetPC(mglevels[0]->smoothd,&cpc);CHKERRQ(ierr);


  /* If user did not provide fine grid operators OR operator was not updated since last global KSPSetOperators() */
  /* so use those from global PC */
  /* Is this what we always want? What if user wants to keep old one? */
  ierr = KSPGetOperatorsSet(mglevels[n-1]->smoothd,NULL,&opsset);CHKERRQ(ierr);
  if (opsset) {
    Mat mmat;
    ierr = KSPGetOperators(mglevels[n-1]->smoothd,NULL,&mmat);CHKERRQ(ierr);
    if (mmat == pc->pmat) opsset = PETSC_FALSE;
  }

  if (!opsset) {
    ierr = PCGetUseAmat(pc,&use_amat);CHKERRQ(ierr);
    if(use_amat){
      ierr = PetscInfo(pc,"Using outer operators to define finest grid operator \n  because PCMGGetSmoother(pc,nlevels-1,&ksp);KSPSetOperators(ksp,...); was not called.\n");CHKERRQ(ierr);
      ierr = KSPSetOperators(mglevels[n-1]->smoothd,pc->mat,pc->pmat);CHKERRQ(ierr);
    }
    else {
      ierr = PetscInfo(pc,"Using matrix (pmat) operators to define finest grid operator \n  because PCMGGetSmoother(pc,nlevels-1,&ksp);KSPSetOperators(ksp,...); was not called.\n");CHKERRQ(ierr);
      ierr = KSPSetOperators(mglevels[n-1]->smoothd,pc->pmat,pc->pmat);CHKERRQ(ierr);
    }
  }

  for (i=n-1; i>0; i--) {
    if (!(mglevels[i]->interpolate || mglevels[i]->restrct)) {
      missinginterpolate = PETSC_TRUE;
      continue;
    }
  }
  /*
   Skipping if user has provided all interpolation/restriction needed (since DM might not be able to produce them (when coming from SNES/TS)
   Skipping for galerkin==2 (externally managed hierarchy such as ML and GAMG). Cleaner logic here would be great. Wrap ML/GAMG as DMs?
  */
  if (missinginterpolate && pc->dm && mg->galerkin != 2 && !pc->setupcalled) {
    /* construct the interpolation from the DMs */
    Mat p;
    Vec rscale;
    ierr     = PetscMalloc1(n,&dms);CHKERRQ(ierr);
    dms[n-1] = pc->dm;
    /* Separately create them so we do not get DMKSP interference between levels */
    for (i=n-2; i>-1; i--) {ierr = DMCoarsen(dms[i+1],MPI_COMM_NULL,&dms[i]);CHKERRQ(ierr);}
    for (i=n-2; i>-1; i--) {
      DMKSP     kdm;
      PetscBool dmhasrestrict;
      ierr = KSPSetDM(mglevels[i]->smoothd,dms[i]);CHKERRQ(ierr);
      if (mg->galerkin) {ierr = KSPSetDMActive(mglevels[i]->smoothd,PETSC_FALSE);CHKERRQ(ierr);}
      ierr = DMGetDMKSPWrite(dms[i],&kdm);CHKERRQ(ierr);
      /* Ugly hack so that the next KSPSetUp() will use the RHS that we set. A better fix is to change dmActive to take
       * a bitwise OR of computing the matrix, RHS, and initial iterate. */
      kdm->ops->computerhs = NULL;
      kdm->rhsctx          = NULL;
      if (!mglevels[i+1]->interpolate) {
        ierr = DMCreateInterpolation(dms[i],dms[i+1],&p,&rscale);CHKERRQ(ierr);
        ierr = PCMGSetInterpolation(pc,i+1,p);CHKERRQ(ierr);
        if (rscale) {ierr = PCMGSetRScale(pc,i+1,rscale);CHKERRQ(ierr);}
        ierr = VecDestroy(&rscale);CHKERRQ(ierr);
        ierr = MatDestroy(&p);CHKERRQ(ierr);
      }
      ierr = DMHasCreateRestriction(dms[i],&dmhasrestrict);CHKERRQ(ierr);
      if (dmhasrestrict && !mglevels[i+1]->restrct){
        ierr = DMCreateRestriction(dms[i],dms[i+1],&p);CHKERRQ(ierr);
        ierr = PCMGSetRestriction(pc,i+1,p);CHKERRQ(ierr);
        ierr = MatDestroy(&p);CHKERRQ(ierr);
      }
    }

    for (i=n-2; i>-1; i--) {ierr = DMDestroy(&dms[i]);CHKERRQ(ierr);}
    ierr = PetscFree(dms);CHKERRQ(ierr);
  }

  if (pc->dm && !pc->setupcalled) {
    /* finest smoother also gets DM but it is not active, independent of whether galerkin==2 */
    ierr = KSPSetDM(mglevels[n-1]->smoothd,pc->dm);CHKERRQ(ierr);
    ierr = KSPSetDMActive(mglevels[n-1]->smoothd,PETSC_FALSE);CHKERRQ(ierr);
  }

  if (mg->galerkin == 1) {
    Mat B;
    /* currently only handle case where mat and pmat are the same on coarser levels */
    ierr = KSPGetOperators(mglevels[n-1]->smoothd,&dA,&dB);CHKERRQ(ierr);
    if (!pc->setupcalled) {
      for (i=n-2; i>-1; i--) {
        if (!mglevels[i+1]->restrct && !mglevels[i+1]->interpolate) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Must provide interpolation or restriction for each MG level except level 0");
        if (!mglevels[i+1]->interpolate) {
          ierr = PCMGSetInterpolation(pc,i+1,mglevels[i+1]->restrct);CHKERRQ(ierr);
        }
        if (!mglevels[i+1]->restrct) {
          ierr = PCMGSetRestriction(pc,i+1,mglevels[i+1]->interpolate);CHKERRQ(ierr);
        }
        if (mglevels[i+1]->interpolate == mglevels[i+1]->restrct) {
          ierr = MatPtAP(dB,mglevels[i+1]->interpolate,MAT_INITIAL_MATRIX,1.0,&B);CHKERRQ(ierr);
        } else {
          ierr = MatMatMatMult(mglevels[i+1]->restrct,dB,mglevels[i+1]->interpolate,MAT_INITIAL_MATRIX,1.0,&B);CHKERRQ(ierr);
        }
        ierr = KSPSetOperators(mglevels[i]->smoothd,B,B);CHKERRQ(ierr);
        if (i != n-2) {ierr = PetscObjectDereference((PetscObject)dB);CHKERRQ(ierr);}
        dB = B;
      }
      if (n > 1) {ierr = PetscObjectDereference((PetscObject)dB);CHKERRQ(ierr);}
    } else {
      for (i=n-2; i>-1; i--) {
        if (!mglevels[i+1]->restrct && !mglevels[i+1]->interpolate) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Must provide interpolation or restriction for each MG level except level 0");
        if (!mglevels[i+1]->interpolate) {
          ierr = PCMGSetInterpolation(pc,i+1,mglevels[i+1]->restrct);CHKERRQ(ierr);
        }
        if (!mglevels[i+1]->restrct) {
          ierr = PCMGSetRestriction(pc,i+1,mglevels[i+1]->interpolate);CHKERRQ(ierr);
        }
        ierr = KSPGetOperators(mglevels[i]->smoothd,NULL,&B);CHKERRQ(ierr);
        if (mglevels[i+1]->interpolate == mglevels[i+1]->restrct) {
          ierr = MatPtAP(dB,mglevels[i+1]->interpolate,MAT_REUSE_MATRIX,1.0,&B);CHKERRQ(ierr);
        } else {
          ierr = MatMatMatMult(mglevels[i+1]->restrct,dB,mglevels[i+1]->interpolate,MAT_REUSE_MATRIX,1.0,&B);CHKERRQ(ierr);
        }
        ierr = KSPSetOperators(mglevels[i]->smoothd,B,B);CHKERRQ(ierr);
        dB   = B;
      }
    }
  } else if (!mg->galerkin && pc->dm && pc->dm->x) {
    /* need to restrict Jacobian location to coarser meshes for evaluation */
    for (i=n-2; i>-1; i--) {
      Mat R;
      Vec rscale;
      if (!mglevels[i]->smoothd->dm->x) {
        Vec *vecs;
        ierr = KSPCreateVecs(mglevels[i]->smoothd,1,&vecs,0,NULL);CHKERRQ(ierr);
        mglevels[i]->smoothd->dm->x = vecs[0];
        ierr = PetscFree(vecs);CHKERRQ(ierr);
      }
      ierr = PCMGGetRestriction(pc,i+1,&R);CHKERRQ(ierr);
      ierr = PCMGGetRScale(pc,i+1,&rscale);CHKERRQ(ierr);
      ierr = MatRestrict(R,mglevels[i+1]->smoothd->dm->x,mglevels[i]->smoothd->dm->x);CHKERRQ(ierr);
      ierr = VecPointwiseMult(mglevels[i]->smoothd->dm->x,mglevels[i]->smoothd->dm->x,rscale);CHKERRQ(ierr);
    }
  }
  if (!mg->galerkin && pc->dm) {
    for (i=n-2; i>=0; i--) {
      DM  dmfine,dmcoarse;
      Mat Restrict,Inject;
      Vec rscale;
      ierr   = KSPGetDM(mglevels[i+1]->smoothd,&dmfine);CHKERRQ(ierr);
      ierr   = KSPGetDM(mglevels[i]->smoothd,&dmcoarse);CHKERRQ(ierr);
      ierr   = PCMGGetRestriction(pc,i+1,&Restrict);CHKERRQ(ierr);
      ierr   = PCMGGetRScale(pc,i+1,&rscale);CHKERRQ(ierr);
      Inject = NULL;      /* Callback should create it if it needs Injection */
      ierr   = DMRestrict(dmfine,Restrict,rscale,Inject,dmcoarse);CHKERRQ(ierr);
    }
  }

  if (!pc->setupcalled) {
    for (i=0; i<n; i++) {
      ierr = KSPSetFromOptions(mglevels[i]->smoothd);CHKERRQ(ierr);
    }
    for (i=1; i<n; i++) {
      if (mglevels[i]->smoothu && (mglevels[i]->smoothu != mglevels[i]->smoothd)) {
        ierr = KSPSetFromOptions(mglevels[i]->smoothu);CHKERRQ(ierr);
      }
    }
    /* insure that if either interpolation or restriction is set the other other one is set */
    for (i=1; i<n; i++) {
      ierr = PCMGGetInterpolation(pc,i,NULL);CHKERRQ(ierr);
      ierr = PCMGGetRestriction(pc,i,NULL);CHKERRQ(ierr);
    }
    for (i=0; i<n-1; i++) {
      if (!mglevels[i]->b) {
        Vec *vec;
        ierr = KSPCreateVecs(mglevels[i]->smoothd,1,&vec,0,NULL);CHKERRQ(ierr);
        ierr = PCMGSetRhs(pc,i,*vec);CHKERRQ(ierr);
        ierr = VecDestroy(vec);CHKERRQ(ierr);
        ierr = PetscFree(vec);CHKERRQ(ierr);
      }
      if (!mglevels[i]->r && i) {
        ierr = VecDuplicate(mglevels[i]->b,&tvec);CHKERRQ(ierr);
        ierr = PCMGSetR(pc,i,tvec);CHKERRQ(ierr);
        ierr = VecDestroy(&tvec);CHKERRQ(ierr);
      }
      if (!mglevels[i]->x) {
        ierr = VecDuplicate(mglevels[i]->b,&tvec);CHKERRQ(ierr);
        ierr = PCMGSetX(pc,i,tvec);CHKERRQ(ierr);
        ierr = VecDestroy(&tvec);CHKERRQ(ierr);
      }
    }
    if (n != 1 && !mglevels[n-1]->r) {
      /* PCMGSetR() on the finest level if user did not supply it */
      Vec *vec;
      ierr = KSPCreateVecs(mglevels[n-1]->smoothd,1,&vec,0,NULL);CHKERRQ(ierr);
      ierr = PCMGSetR(pc,n-1,*vec);CHKERRQ(ierr);
      ierr = VecDestroy(vec);CHKERRQ(ierr);
      ierr = PetscFree(vec);CHKERRQ(ierr);
    }
  }

  if (pc->dm) {
    /* need to tell all the coarser levels to rebuild the matrix using the DM for that level */
    for (i=0; i<n-1; i++) {
      if (mglevels[i]->smoothd->setupstage != KSP_SETUP_NEW) mglevels[i]->smoothd->setupstage = KSP_SETUP_NEWMATRIX;
    }
  }

  for (i=1; i<n; i++) {
    if (mglevels[i]->smoothu == mglevels[i]->smoothd || mg->am == PC_MG_FULL || mg->am == PC_MG_KASKADE || mg->cyclesperpcapply > 1){
      /* if doing only down then initial guess is zero */
      ierr = KSPSetInitialGuessNonzero(mglevels[i]->smoothd,PETSC_TRUE);CHKERRQ(ierr);
    }
    if (mglevels[i]->eventsmoothsetup) {ierr = PetscLogEventBegin(mglevels[i]->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
    ierr = KSPSetUp(mglevels[i]->smoothd);CHKERRQ(ierr);
    if (mglevels[i]->smoothd->reason == KSP_DIVERGED_PCSETUP_FAILED) {
      pc->failedreason = PC_SUBPC_ERROR;
    }
    if (mglevels[i]->eventsmoothsetup) {ierr = PetscLogEventEnd(mglevels[i]->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
    if (!mglevels[i]->residual) {
      Mat mat;
      ierr = KSPGetOperators(mglevels[i]->smoothd,NULL,&mat);CHKERRQ(ierr);
      ierr = PCMGSetResidual(pc,i,PCMGResidualDefault,mat);CHKERRQ(ierr);
    }
  }
  for (i=1; i<n; i++) {
    if (mglevels[i]->smoothu && mglevels[i]->smoothu != mglevels[i]->smoothd) {
      Mat          downmat,downpmat;

      /* check if operators have been set for up, if not use down operators to set them */
      ierr = KSPGetOperatorsSet(mglevels[i]->smoothu,&opsset,NULL);CHKERRQ(ierr);
      if (!opsset) {
        ierr = KSPGetOperators(mglevels[i]->smoothd,&downmat,&downpmat);CHKERRQ(ierr);
        ierr = KSPSetOperators(mglevels[i]->smoothu,downmat,downpmat);CHKERRQ(ierr);
      }

      ierr = KSPSetInitialGuessNonzero(mglevels[i]->smoothu,PETSC_TRUE);CHKERRQ(ierr);
      if (mglevels[i]->eventsmoothsetup) {ierr = PetscLogEventBegin(mglevels[i]->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
      ierr = KSPSetUp(mglevels[i]->smoothu);CHKERRQ(ierr);
      if (mglevels[i]->smoothu->reason == KSP_DIVERGED_PCSETUP_FAILED) {
        pc->failedreason = PC_SUBPC_ERROR;
      }
      if (mglevels[i]->eventsmoothsetup) {ierr = PetscLogEventEnd(mglevels[i]->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
    }
  }

  if (mglevels[0]->eventsmoothsetup) {ierr = PetscLogEventBegin(mglevels[0]->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
  ierr = KSPSetUp(mglevels[0]->smoothd);CHKERRQ(ierr);
  if (mglevels[0]->smoothd->reason == KSP_DIVERGED_PCSETUP_FAILED) {
    pc->failedreason = PC_SUBPC_ERROR;
  }
  if (mglevels[0]->eventsmoothsetup) {ierr = PetscLogEventEnd(mglevels[0]->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}

  /*
     Dump the interpolation/restriction matrices plus the
   Jacobian/stiffness on each level. This allows MATLAB users to
   easily check if the Galerkin condition A_c = R A_f R^T is satisfied.

   Only support one or the other at the same time.
  */
#if defined(PETSC_USE_SOCKET_VIEWER)
  ierr = PetscOptionsGetBool(((PetscObject)pc)->options,((PetscObject)pc)->prefix,"-pc_mg_dump_matlab",&dump,NULL);CHKERRQ(ierr);
  if (dump) viewer = PETSC_VIEWER_SOCKET_(PetscObjectComm((PetscObject)pc));
  dump = PETSC_FALSE;
#endif
  ierr = PetscOptionsGetBool(((PetscObject)pc)->options,((PetscObject)pc)->prefix,"-pc_mg_dump_binary",&dump,NULL);CHKERRQ(ierr);
  if (dump) viewer = PETSC_VIEWER_BINARY_(PetscObjectComm((PetscObject)pc));

  if (viewer) {
    for (i=1; i<n; i++) {
      ierr = MatView(mglevels[i]->restrct,viewer);CHKERRQ(ierr);
    }
    for (i=0; i<n; i++) {
      ierr = KSPGetPC(mglevels[i]->smoothd,&pc);CHKERRQ(ierr);
      ierr = MatView(pc->mat,viewer);CHKERRQ(ierr);
    }
  }
  PetscFunctionReturn(0);
}
Example #4
0
File: mg.c Project: ziolai/petsc
PetscErrorCode PCSetFromOptions_MG(PetscOptionItems *PetscOptionsObject,PC pc)
{
  PetscErrorCode ierr;
  PetscInt       m,levels = 1,cycles;
  PetscBool      flg,set;
  PC_MG          *mg        = (PC_MG*)pc->data;
  PC_MG_Levels   **mglevels;
  PCMGType       mgtype;
  PCMGCycleType  mgctype;

  PetscFunctionBegin;
  ierr = PetscOptionsHead(PetscOptionsObject,"Multigrid options");CHKERRQ(ierr);
  if (!mg->levels) {
    ierr = PetscOptionsInt("-pc_mg_levels","Number of Levels","PCMGSetLevels",levels,&levels,&flg);CHKERRQ(ierr);
    if (!flg && pc->dm) {
      ierr = DMGetRefineLevel(pc->dm,&levels);CHKERRQ(ierr);
      levels++;
      mg->usedmfornumberoflevels = PETSC_TRUE;
    }
    ierr = PCMGSetLevels(pc,levels,NULL);CHKERRQ(ierr);
  }
  mglevels = mg->levels;

  mgctype = (PCMGCycleType) mglevels[0]->cycles;
  ierr    = PetscOptionsEnum("-pc_mg_cycle_type","V cycle or for W-cycle","PCMGSetCycleType",PCMGCycleTypes,(PetscEnum)mgctype,(PetscEnum*)&mgctype,&flg);CHKERRQ(ierr);
  if (flg) {
    ierr = PCMGSetCycleType(pc,mgctype);CHKERRQ(ierr);
  }
  flg  = PETSC_FALSE;
  ierr = PetscOptionsBool("-pc_mg_galerkin","Use Galerkin process to compute coarser operators","PCMGSetGalerkin",flg,&flg,&set);CHKERRQ(ierr);
  if (set) {
    ierr = PCMGSetGalerkin(pc,flg);CHKERRQ(ierr);
  }
  ierr = PetscOptionsInt("-pc_mg_smoothup","Number of post-smoothing steps","PCMGSetNumberSmoothUp",mg->default_smoothu,&m,&flg);CHKERRQ(ierr);
  if (flg) {
    ierr = PCMGSetNumberSmoothUp(pc,m);CHKERRQ(ierr);
  }
  ierr = PetscOptionsInt("-pc_mg_smoothdown","Number of pre-smoothing steps","PCMGSetNumberSmoothDown",mg->default_smoothd,&m,&flg);CHKERRQ(ierr);
  if (flg) {
    ierr = PCMGSetNumberSmoothDown(pc,m);CHKERRQ(ierr);
  }
  mgtype = mg->am;
  ierr   = PetscOptionsEnum("-pc_mg_type","Multigrid type","PCMGSetType",PCMGTypes,(PetscEnum)mgtype,(PetscEnum*)&mgtype,&flg);CHKERRQ(ierr);
  if (flg) {
    ierr = PCMGSetType(pc,mgtype);CHKERRQ(ierr);
  }
  if (mg->am == PC_MG_MULTIPLICATIVE) {
    ierr = PetscOptionsInt("-pc_mg_multiplicative_cycles","Number of cycles for each preconditioner step","PCMGMultiplicativeSetCycles",mg->cyclesperpcapply,&cycles,&flg);CHKERRQ(ierr);
    if (flg) {
      ierr = PCMGMultiplicativeSetCycles(pc,cycles);CHKERRQ(ierr);
    }
  }
  flg  = PETSC_FALSE;
  ierr = PetscOptionsBool("-pc_mg_log","Log times for each multigrid level","None",flg,&flg,NULL);CHKERRQ(ierr);
  if (flg) {
    PetscInt i;
    char     eventname[128];
    if (!mglevels) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Must set MG levels before calling");
    levels = mglevels[0]->levels;
    for (i=0; i<levels; i++) {
      sprintf(eventname,"MGSetup Level %d",(int)i);
      ierr = PetscLogEventRegister(eventname,((PetscObject)pc)->classid,&mglevels[i]->eventsmoothsetup);CHKERRQ(ierr);
      sprintf(eventname,"MGSmooth Level %d",(int)i);
      ierr = PetscLogEventRegister(eventname,((PetscObject)pc)->classid,&mglevels[i]->eventsmoothsolve);CHKERRQ(ierr);
      if (i) {
        sprintf(eventname,"MGResid Level %d",(int)i);
        ierr = PetscLogEventRegister(eventname,((PetscObject)pc)->classid,&mglevels[i]->eventresidual);CHKERRQ(ierr);
        sprintf(eventname,"MGInterp Level %d",(int)i);
        ierr = PetscLogEventRegister(eventname,((PetscObject)pc)->classid,&mglevels[i]->eventinterprestrict);CHKERRQ(ierr);
      }
    }

#if defined(PETSC_USE_LOG)
    {
      const char    *sname = "MG Apply";
      PetscStageLog stageLog;
      PetscInt      st;

      PetscFunctionBegin;
      ierr = PetscLogGetStageLog(&stageLog);CHKERRQ(ierr);
      for (st = 0; st < stageLog->numStages; ++st) {
        PetscBool same;

        ierr = PetscStrcmp(stageLog->stageInfo[st].name, sname, &same);CHKERRQ(ierr);
        if (same) mg->stageApply = st;
      }
      if (!mg->stageApply) {
        ierr = PetscLogStageRegister(sname, &mg->stageApply);CHKERRQ(ierr);
      }
    }
#endif
  }
  ierr = PetscOptionsTail();CHKERRQ(ierr);
  PetscFunctionReturn(0);
}
Example #5
0
File: fas.c Project: fengyuqi/petsc
PetscErrorCode SNESSetFromOptions_FAS(PetscOptions *PetscOptionsObject,SNES snes)
{
  SNES_FAS       *fas   = (SNES_FAS*) snes->data;
  PetscInt       levels = 1;
  PetscBool      flg    = PETSC_FALSE, upflg = PETSC_FALSE, downflg = PETSC_FALSE, monflg = PETSC_FALSE, galerkinflg = PETSC_FALSE,continuationflg = PETSC_FALSE;
  PetscErrorCode ierr;
  char           monfilename[PETSC_MAX_PATH_LEN];
  SNESFASType    fastype;
  const char     *optionsprefix;
  SNESLineSearch linesearch;
  PetscInt       m, n_up, n_down;
  SNES           next;
  PetscBool      isFine;

  PetscFunctionBegin;
  ierr = SNESFASCycleIsFine(snes, &isFine);CHKERRQ(ierr);
  ierr = PetscOptionsHead(PetscOptionsObject,"SNESFAS Options-----------------------------------");CHKERRQ(ierr);

  /* number of levels -- only process most options on the finest level */
  if (isFine) {
    ierr = PetscOptionsInt("-snes_fas_levels", "Number of Levels", "SNESFASSetLevels", levels, &levels, &flg);CHKERRQ(ierr);
    if (!flg && snes->dm) {
      ierr = DMGetRefineLevel(snes->dm,&levels);CHKERRQ(ierr);
      levels++;
      fas->usedmfornumberoflevels = PETSC_TRUE;
    }
    ierr    = SNESFASSetLevels(snes, levels, NULL);CHKERRQ(ierr);
    fastype = fas->fastype;
    ierr    = PetscOptionsEnum("-snes_fas_type","FAS correction type","SNESFASSetType",SNESFASTypes,(PetscEnum)fastype,(PetscEnum*)&fastype,&flg);CHKERRQ(ierr);
    if (flg) {
      ierr = SNESFASSetType(snes, fastype);CHKERRQ(ierr);
    }

    ierr = SNESGetOptionsPrefix(snes, &optionsprefix);CHKERRQ(ierr);
    ierr = PetscOptionsInt("-snes_fas_cycles","Number of cycles","SNESFASSetCycles",fas->n_cycles,&m,&flg);CHKERRQ(ierr);
    if (flg) {
      ierr = SNESFASSetCycles(snes, m);CHKERRQ(ierr);
    }
    ierr = PetscOptionsBool("-snes_fas_continuation","Corrected grid-sequence continuation","SNESFASSetContinuation",fas->continuation,&continuationflg,&flg);CHKERRQ(ierr);
    if (flg) {
      ierr = SNESFASSetContinuation(snes,continuationflg);CHKERRQ(ierr);
    }

    ierr = PetscOptionsBool("-snes_fas_galerkin", "Form coarse problems with Galerkin","SNESFASSetGalerkin",fas->galerkin,&galerkinflg,&flg);CHKERRQ(ierr);
    if (flg) {
      ierr = SNESFASSetGalerkin(snes, galerkinflg);CHKERRQ(ierr);
    }

    if (fas->fastype == SNES_FAS_FULL) {
      ierr   = PetscOptionsBool("-snes_fas_full_downsweep","Smooth on the initial upsweep for full FAS cycles","SNESFASFullSetDownSweep",fas->full_downsweep,&fas->full_downsweep,&flg);CHKERRQ(ierr);
      if (flg) {SNESFASFullSetDownSweep(snes,fas->full_downsweep);CHKERRQ(ierr);}
    }

    ierr = PetscOptionsInt("-snes_fas_smoothup","Number of post-smoothing steps","SNESFASSetNumberSmoothUp",fas->max_up_it,&n_up,&upflg);CHKERRQ(ierr);

    ierr = PetscOptionsInt("-snes_fas_smoothdown","Number of pre-smoothing steps","SNESFASSetNumberSmoothDown",fas->max_down_it,&n_down,&downflg);CHKERRQ(ierr);

    ierr = PetscOptionsString("-snes_fas_monitor","Monitor FAS progress","SNESFASSetMonitor","stdout",monfilename,PETSC_MAX_PATH_LEN,&monflg);CHKERRQ(ierr);
    if (monflg) ierr = SNESFASSetMonitor(snes, PETSC_TRUE);CHKERRQ(ierr);

    flg    = PETSC_FALSE;
    monflg = PETSC_TRUE;
    ierr   = PetscOptionsBool("-snes_fas_log","Log times for each FAS level","SNESFASSetLog",monflg,&monflg,&flg);CHKERRQ(ierr);
    if (flg) {ierr = SNESFASSetLog(snes,monflg);CHKERRQ(ierr);}
  }

  ierr = PetscOptionsTail();CHKERRQ(ierr);
  /* setup from the determined types if there is no pointwise procedure or smoother defined */
  if (upflg) {
    ierr = SNESFASSetNumberSmoothUp(snes,n_up);CHKERRQ(ierr);
  }
  if (downflg) {
    ierr = SNESFASSetNumberSmoothDown(snes,n_down);CHKERRQ(ierr);
  }

  /* set up the default line search for coarse grid corrections */
  if (fas->fastype == SNES_FAS_ADDITIVE) {
    if (!snes->linesearch) {
      ierr = SNESGetLineSearch(snes, &linesearch);CHKERRQ(ierr);
      ierr = SNESLineSearchSetType(linesearch, SNESLINESEARCHL2);CHKERRQ(ierr);
    }
  }

  ierr = SNESFASCycleGetCorrection(snes, &next);CHKERRQ(ierr);
  /* recursive option setting for the smoothers */
  if (next) {ierr = SNESSetFromOptions(next);CHKERRQ(ierr);}
  PetscFunctionReturn(0);
}
Example #6
0
File: fas.c Project: fengyuqi/petsc
PetscErrorCode SNESSetUp_FAS(SNES snes)
{
  SNES_FAS       *fas = (SNES_FAS*) snes->data;
  PetscErrorCode ierr;
  PetscInt       dm_levels;
  Vec            vec_sol, vec_func, vec_sol_update, vec_rhs; /* preserve these if they're set through the reset */
  SNES           next;
  PetscBool      isFine;
  SNESLineSearch linesearch;
  SNESLineSearch slinesearch;
  void           *lsprectx,*lspostctx;
  PetscErrorCode (*precheck)(SNESLineSearch,Vec,Vec,PetscBool*,void*);
  PetscErrorCode (*postcheck)(SNESLineSearch,Vec,Vec,Vec,PetscBool*,PetscBool*,void*);

  PetscFunctionBegin;
  ierr = SNESFASCycleIsFine(snes, &isFine);CHKERRQ(ierr);
  if (fas->usedmfornumberoflevels && isFine) {
    ierr = DMGetRefineLevel(snes->dm,&dm_levels);CHKERRQ(ierr);
    dm_levels++;
    if (dm_levels > fas->levels) {
      /* we don't want the solution and func vectors to be destroyed in the SNESReset when it's called in SNESFASSetLevels_FAS*/
      vec_sol              = snes->vec_sol;
      vec_func             = snes->vec_func;
      vec_sol_update       = snes->vec_sol_update;
      vec_rhs              = snes->vec_rhs;
      snes->vec_sol        = NULL;
      snes->vec_func       = NULL;
      snes->vec_sol_update = NULL;
      snes->vec_rhs        = NULL;

      /* reset the number of levels */
      ierr = SNESFASSetLevels(snes,dm_levels,NULL);CHKERRQ(ierr);
      ierr = SNESSetFromOptions(snes);CHKERRQ(ierr);

      snes->vec_sol        = vec_sol;
      snes->vec_func       = vec_func;
      snes->vec_rhs        = vec_rhs;
      snes->vec_sol_update = vec_sol_update;
    }
  }
  ierr = SNESFASCycleGetCorrection(snes, &next);CHKERRQ(ierr);
  if (!isFine) snes->gridsequence = 0; /* no grid sequencing inside the multigrid hierarchy! */

  ierr = SNESSetWorkVecs(snes, 2);CHKERRQ(ierr); /* work vectors used for intergrid transfers */

  /* set up the smoothers if they haven't already been set up */
  if (!fas->smoothd) {
    ierr = SNESFASCycleCreateSmoother_Private(snes, &fas->smoothd);CHKERRQ(ierr);
  }

  if (snes->dm) {
    /* set the smoother DMs properly */
    if (fas->smoothu) ierr = SNESSetDM(fas->smoothu, snes->dm);CHKERRQ(ierr);
    ierr = SNESSetDM(fas->smoothd, snes->dm);CHKERRQ(ierr);
    /* construct EVERYTHING from the DM -- including the progressive set of smoothers */
    if (next) {
      /* for now -- assume the DM and the evaluation functions have been set externally */
      if (!next->dm) {
        ierr = DMCoarsen(snes->dm, PetscObjectComm((PetscObject)next), &next->dm);CHKERRQ(ierr);
        ierr = SNESSetDM(next, next->dm);CHKERRQ(ierr);
      }
      /* set the interpolation and restriction from the DM */
      if (!fas->interpolate) {
        ierr = DMCreateInterpolation(next->dm, snes->dm, &fas->interpolate, &fas->rscale);CHKERRQ(ierr);
        if (!fas->restrct) {
          ierr         = PetscObjectReference((PetscObject)fas->interpolate);CHKERRQ(ierr);
          fas->restrct = fas->interpolate;
        }
      }
      /* set the injection from the DM */
      if (!fas->inject) {
        ierr = DMCreateInjection(next->dm, snes->dm, &fas->inject);CHKERRQ(ierr);
      }
    }
  }
  /*pass the smoother, function, and jacobian up to the next level if it's not user set already */
  if (fas->galerkin) {
    if (next) {
      ierr = SNESSetFunction(next, NULL, SNESFASGalerkinDefaultFunction, next);CHKERRQ(ierr);
    }
    if (fas->smoothd && fas->level != fas->levels - 1) {
      ierr = SNESSetFunction(fas->smoothd, NULL, SNESFASGalerkinDefaultFunction, snes);CHKERRQ(ierr);
    }
    if (fas->smoothu && fas->level != fas->levels - 1) {
      ierr = SNESSetFunction(fas->smoothu, NULL, SNESFASGalerkinDefaultFunction, snes);CHKERRQ(ierr);
    }
  }

  /* sets the down (pre) smoother's default norm and sets it from options */
  if (fas->smoothd) {
    if (fas->level == 0 && fas->levels != 1) {
      ierr = SNESSetNormSchedule(fas->smoothd, SNES_NORM_NONE);CHKERRQ(ierr);
    } else {
      ierr = SNESSetNormSchedule(fas->smoothd, SNES_NORM_FINAL_ONLY);CHKERRQ(ierr);
    }
    ierr = PetscObjectCopyFortranFunctionPointers((PetscObject)snes, (PetscObject)fas->smoothd);CHKERRQ(ierr);
    ierr = SNESSetFromOptions(fas->smoothd);CHKERRQ(ierr);
    ierr = SNESGetLineSearch(snes,&linesearch);CHKERRQ(ierr);
    ierr = SNESGetLineSearch(fas->smoothd,&slinesearch);CHKERRQ(ierr);
    ierr = SNESLineSearchGetPreCheck(linesearch,&precheck,&lsprectx);CHKERRQ(ierr);
    ierr = SNESLineSearchGetPostCheck(linesearch,&postcheck,&lspostctx);CHKERRQ(ierr);
    ierr = SNESLineSearchSetPreCheck(slinesearch,precheck,lsprectx);CHKERRQ(ierr);
    ierr = SNESLineSearchSetPostCheck(slinesearch,postcheck,lspostctx);CHKERRQ(ierr);
    ierr = PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)slinesearch);CHKERRQ(ierr);

    fas->smoothd->vec_sol        = snes->vec_sol;
    ierr                         = PetscObjectReference((PetscObject)snes->vec_sol);CHKERRQ(ierr);
    fas->smoothd->vec_sol_update = snes->vec_sol_update;
    ierr                         = PetscObjectReference((PetscObject)snes->vec_sol_update);CHKERRQ(ierr);
    fas->smoothd->vec_func       = snes->vec_func;
    ierr                         = PetscObjectReference((PetscObject)snes->vec_func);CHKERRQ(ierr);

    if (fas->eventsmoothsetup) {ierr = PetscLogEventBegin(fas->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
    ierr = SNESSetUp(fas->smoothd);CHKERRQ(ierr);
    if (fas->eventsmoothsetup) {ierr = PetscLogEventEnd(fas->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
  }

  /* sets the up (post) smoother's default norm and sets it from options */
  if (fas->smoothu) {
    if (fas->level != fas->levels - 1) {
      ierr = SNESSetNormSchedule(fas->smoothu, SNES_NORM_NONE);CHKERRQ(ierr);
    } else {
      ierr = SNESSetNormSchedule(fas->smoothu, SNES_NORM_FINAL_ONLY);CHKERRQ(ierr);
    }
    ierr = PetscObjectCopyFortranFunctionPointers((PetscObject)snes, (PetscObject)fas->smoothu);CHKERRQ(ierr);
    ierr = SNESSetFromOptions(fas->smoothu);CHKERRQ(ierr);
    ierr = SNESGetLineSearch(snes,&linesearch);CHKERRQ(ierr);
    ierr = SNESGetLineSearch(fas->smoothu,&slinesearch);CHKERRQ(ierr);
    ierr = SNESLineSearchGetPreCheck(linesearch,&precheck,&lsprectx);CHKERRQ(ierr);
    ierr = SNESLineSearchGetPostCheck(linesearch,&postcheck,&lspostctx);CHKERRQ(ierr);
    ierr = SNESLineSearchSetPreCheck(slinesearch,precheck,lsprectx);CHKERRQ(ierr);
    ierr = SNESLineSearchSetPostCheck(slinesearch,postcheck,lspostctx);CHKERRQ(ierr);
    ierr = PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)slinesearch);CHKERRQ(ierr);

    fas->smoothu->vec_sol        = snes->vec_sol;
    ierr                         = PetscObjectReference((PetscObject)snes->vec_sol);CHKERRQ(ierr);
    fas->smoothu->vec_sol_update = snes->vec_sol_update;
    ierr                         = PetscObjectReference((PetscObject)snes->vec_sol_update);CHKERRQ(ierr);
    fas->smoothu->vec_func       = snes->vec_func;
    ierr                         = PetscObjectReference((PetscObject)snes->vec_func);CHKERRQ(ierr);

    if (fas->eventsmoothsetup) {ierr = PetscLogEventBegin(fas->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
    ierr = SNESSetUp(fas->smoothu);CHKERRQ(ierr);
    if (fas->eventsmoothsetup) {ierr = PetscLogEventEnd(fas->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}

  }

  if (next) {
    /* gotta set up the solution vector for this to work */
    if (!next->vec_sol) {ierr = SNESFASCreateCoarseVec(snes,&next->vec_sol);CHKERRQ(ierr);}
    if (!next->vec_rhs) {ierr = SNESFASCreateCoarseVec(snes,&next->vec_rhs);CHKERRQ(ierr);}
    ierr = PetscObjectCopyFortranFunctionPointers((PetscObject)snes, (PetscObject)next);CHKERRQ(ierr);
    ierr = SNESGetLineSearch(snes,&linesearch);CHKERRQ(ierr);
    ierr = SNESGetLineSearch(fas->next,&slinesearch);CHKERRQ(ierr);
    ierr = SNESLineSearchGetPreCheck(linesearch,&precheck,&lsprectx);CHKERRQ(ierr);
    ierr = SNESLineSearchGetPostCheck(linesearch,&postcheck,&lspostctx);CHKERRQ(ierr);
    ierr = SNESLineSearchSetPreCheck(slinesearch,precheck,lsprectx);CHKERRQ(ierr);
    ierr = SNESLineSearchSetPostCheck(slinesearch,postcheck,lspostctx);CHKERRQ(ierr);
    ierr = PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)slinesearch);CHKERRQ(ierr);
    ierr = SNESSetUp(next);CHKERRQ(ierr);
  }
  /* setup FAS work vectors */
  if (fas->galerkin) {
    ierr = VecDuplicate(snes->vec_sol, &fas->Xg);CHKERRQ(ierr);
    ierr = VecDuplicate(snes->vec_sol, &fas->Fg);CHKERRQ(ierr);
  }
  PetscFunctionReturn(0);
}
Example #7
0
/*@
  PetscConvEstGetConvRate - Returns an estimate of the convergence rate for the discretization

  Not collective

  Input Parameter:
. ce   - The PetscConvEst object

  Output Parameter:
. alpha - The convergence rate for each field

  Note: The convergence rate alpha is defined by
$ || u_h - u_exact || < C h^alpha
where u_h is the discrete solution, and h is a measure of the discretization size.

We solve a series of problems on refined meshes, calculate an error based upon the exact solution in the DS,
and then fit the result to our model above using linear regression.

  Options database keys:
. -snes_convergence_estimate : Execute convergence estimation and print out the rate

  Level: intermediate

.keywords: PetscConvEst, convergence
.seealso: PetscConvEstSetSolver(), PetscConvEstCreate(), PetscConvEstGetConvRate()
@*/
PetscErrorCode PetscConvEstGetConvRate(PetscConvEst ce, PetscReal alpha[])
{
  DM            *dm;
  PetscObject    disc;
  MPI_Comm       comm;
  const char    *uname, *dmname;
  void          *ctx;
  Vec            u;
  PetscReal      t = 0.0, *x, *y, slope, intercept;
  PetscInt      *dof, dim, Nr = ce->Nr, r, f, oldlevel, oldnlev;
  PetscLogEvent  event;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  ierr = PetscObjectGetComm((PetscObject) ce, &comm);CHKERRQ(ierr);
  ierr = DMGetDimension(ce->idm, &dim);CHKERRQ(ierr);
  ierr = DMGetApplicationContext(ce->idm, &ctx);CHKERRQ(ierr);
  ierr = DMPlexSetRefinementUniform(ce->idm, PETSC_TRUE);CHKERRQ(ierr);
  ierr = DMGetRefineLevel(ce->idm, &oldlevel);CHKERRQ(ierr);
  ierr = PetscMalloc2((Nr+1), &dm, (Nr+1)*ce->Nf, &dof);CHKERRQ(ierr);
  dm[0]  = ce->idm;
  for (f = 0; f < ce->Nf; ++f) alpha[f] = 0.0;
  /* Loop over meshes */
  ierr = PetscLogEventRegister("ConvEst Error", PETSC_OBJECT_CLASSID, &event);CHKERRQ(ierr);
  for (r = 0; r <= Nr; ++r) {
    PetscLogStage stage;
    char          stageName[PETSC_MAX_PATH_LEN];

    ierr = PetscSNPrintf(stageName, PETSC_MAX_PATH_LEN-1, "ConvEst Refinement Level %D", r);CHKERRQ(ierr);
    ierr = PetscLogStageRegister(stageName, &stage);CHKERRQ(ierr);
    ierr = PetscLogStagePush(stage);CHKERRQ(ierr);
    if (r > 0) {
      ierr = DMRefine(dm[r-1], MPI_COMM_NULL, &dm[r]);CHKERRQ(ierr);
      ierr = DMSetCoarseDM(dm[r], dm[r-1]);CHKERRQ(ierr);
      ierr = DMCopyDisc(ce->idm, dm[r]);CHKERRQ(ierr);
      ierr = DMCopyTransform(ce->idm, dm[r]);CHKERRQ(ierr);
      ierr = PetscObjectGetName((PetscObject) dm[r-1], &dmname);CHKERRQ(ierr);
      ierr = PetscObjectSetName((PetscObject) dm[r], dmname);CHKERRQ(ierr);
      for (f = 0; f <= ce->Nf; ++f) {
        PetscErrorCode (*nspconstr)(DM, PetscInt, MatNullSpace *);
        ierr = DMGetNullSpaceConstructor(dm[r-1], f, &nspconstr);CHKERRQ(ierr);
        ierr = DMSetNullSpaceConstructor(dm[r],   f,  nspconstr);CHKERRQ(ierr);
      }
    }
    ierr = DMViewFromOptions(dm[r], NULL, "-conv_dm_view");CHKERRQ(ierr);
    /* Create solution */
    ierr = DMCreateGlobalVector(dm[r], &u);CHKERRQ(ierr);
    ierr = DMGetField(dm[r], 0, NULL, &disc);CHKERRQ(ierr);
    ierr = PetscObjectGetName(disc, &uname);CHKERRQ(ierr);
    ierr = PetscObjectSetName((PetscObject) u, uname);CHKERRQ(ierr);
    /* Setup solver */
    ierr = SNESReset(ce->snes);CHKERRQ(ierr);
    ierr = SNESSetDM(ce->snes, dm[r]);CHKERRQ(ierr);
    ierr = DMPlexSetSNESLocalFEM(dm[r], ctx, ctx, ctx);CHKERRQ(ierr);
    ierr = SNESSetFromOptions(ce->snes);CHKERRQ(ierr);
    /* Create initial guess */
    ierr = DMProjectFunction(dm[r], t, ce->initGuess, ce->ctxs, INSERT_VALUES, u);CHKERRQ(ierr);
    ierr = SNESSolve(ce->snes, NULL, u);CHKERRQ(ierr);
    ierr = PetscLogEventBegin(event, ce, 0, 0, 0);CHKERRQ(ierr);
    ierr = DMComputeL2FieldDiff(dm[r], t, ce->exactSol, ce->ctxs, u, &ce->errors[r*ce->Nf]);CHKERRQ(ierr);
    ierr = PetscLogEventEnd(event, ce, 0, 0, 0);CHKERRQ(ierr);
    for (f = 0; f < ce->Nf; ++f) {
      PetscSection s, fs;
      PetscInt     lsize;

      /* Could use DMGetOutputDM() to add in Dirichlet dofs */
      ierr = DMGetSection(dm[r], &s);CHKERRQ(ierr);
      ierr = PetscSectionGetField(s, f, &fs);CHKERRQ(ierr);
      ierr = PetscSectionGetConstrainedStorageSize(fs, &lsize);CHKERRQ(ierr);
      ierr = MPI_Allreduce(&lsize, &dof[r*ce->Nf+f], 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject) ce->snes));CHKERRQ(ierr);
      ierr = PetscLogEventSetDof(event, f, dof[r*ce->Nf+f]);CHKERRQ(ierr);
      ierr = PetscLogEventSetError(event, f, ce->errors[r*ce->Nf+f]);CHKERRQ(ierr);
    }
    /* Monitor */
    if (ce->monitor) {
      PetscReal *errors = &ce->errors[r*ce->Nf];

      ierr = PetscPrintf(comm, "L_2 Error: ");CHKERRQ(ierr);
      if (ce->Nf > 1) {ierr = PetscPrintf(comm, "[");CHKERRQ(ierr);}
      for (f = 0; f < ce->Nf; ++f) {
        if (f > 0) {ierr = PetscPrintf(comm, ", ");CHKERRQ(ierr);}
        if (errors[f] < 1.0e-11) {ierr = PetscPrintf(comm, "< 1e-11");CHKERRQ(ierr);}
        else                     {ierr = PetscPrintf(comm, "%g", (double)errors[f]);CHKERRQ(ierr);}
      }
      if (ce->Nf > 1) {ierr = PetscPrintf(comm, "]");CHKERRQ(ierr);}
      ierr = PetscPrintf(comm, "\n");CHKERRQ(ierr);
    }
    if (!r) {
      /* PCReset() does not wipe out the level structure */
      KSP ksp;
      PC  pc;

      ierr = SNESGetKSP(ce->snes, &ksp);CHKERRQ(ierr);
      ierr = KSPGetPC(ksp, &pc);CHKERRQ(ierr);
      ierr = PCMGGetLevels(pc, &oldnlev);CHKERRQ(ierr);
    }
    /* Cleanup */
    ierr = VecDestroy(&u);CHKERRQ(ierr);
    ierr = PetscLogStagePop();CHKERRQ(ierr);
  }
  for (r = 1; r <= Nr; ++r) {
    ierr = DMDestroy(&dm[r]);CHKERRQ(ierr);
  }
  /* Fit convergence rate */
  ierr = PetscMalloc2(Nr+1, &x, Nr+1, &y);CHKERRQ(ierr);
  for (f = 0; f < ce->Nf; ++f) {
    for (r = 0; r <= Nr; ++r) {
      x[r] = PetscLog10Real(dof[r*ce->Nf+f]);
      y[r] = PetscLog10Real(ce->errors[r*ce->Nf+f]);
    }
    ierr = PetscLinearRegression(Nr+1, x, y, &slope, &intercept);CHKERRQ(ierr);
    /* Since h^{-dim} = N, lg err = s lg N + b = -s dim lg h + b */
    alpha[f] = -slope * dim;
  }
  ierr = PetscFree2(x, y);CHKERRQ(ierr);
  ierr = PetscFree2(dm, dof);CHKERRQ(ierr);
  /* Restore solver */
  ierr = SNESReset(ce->snes);CHKERRQ(ierr);
  {
    /* PCReset() does not wipe out the level structure */
    KSP ksp;
    PC  pc;

    ierr = SNESGetKSP(ce->snes, &ksp);CHKERRQ(ierr);
    ierr = KSPGetPC(ksp, &pc);CHKERRQ(ierr);
    ierr = PCMGSetLevels(pc, oldnlev, NULL);CHKERRQ(ierr);
    ierr = DMSetRefineLevel(ce->idm, oldlevel);CHKERRQ(ierr); /* The damn DMCoarsen() calls in PCMG can reset this */
  }
  ierr = SNESSetDM(ce->snes, ce->idm);CHKERRQ(ierr);
  ierr = DMPlexSetSNESLocalFEM(ce->idm, ctx, ctx, ctx);CHKERRQ(ierr);
  ierr = SNESSetFromOptions(ce->snes);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}