xref: /petsc/src/ksp/pc/impls/redundant/redundant.c (revision d3b23db5a7ee1f155504da2761e4a9fbf8c1ff2c)
1dba47a55SKris Buschelman 
24b9ad928SBarry Smith /*
33f457be1SHong Zhang   This file defines a "solve the problem redundantly on each subgroup of processor" preconditioner.
44b9ad928SBarry Smith */
507475bc1SBarry Smith #include <petsc-private/pcimpl.h>
6c6db04a5SJed Brown #include <petscksp.h>           /*I "petscksp.h" I*/
74b9ad928SBarry Smith 
84b9ad928SBarry Smith typedef struct {
93e065800SHong Zhang   KSP          ksp;
104b9ad928SBarry Smith   PC           pc;                   /* actual preconditioner used on each processor */
11ce94432eSBarry Smith   Vec          xsub,ysub;            /* vectors of a subcommunicator to hold parallel vectors of PetscObjectComm((PetscObject)pc) */
123f457be1SHong Zhang   Vec          xdup,ydup;            /* parallel vector that congregates xsub or ysub facilitating vector scattering */
13b3804887SHong Zhang   Mat          pmats;                /* matrix and optional preconditioner matrix belong to a subcommunicator */
143f457be1SHong Zhang   VecScatter   scatterin,scatterout; /* scatter used to move all values to each processor group (subcommunicator) */
15ace3abfcSBarry Smith   PetscBool    useparallelmat;
16c540e29cSHong Zhang   PetscSubcomm psubcomm;
171fbd8f88SHong Zhang   PetscInt     nsubcomm;           /* num of data structure PetscSubcomm */
184b9ad928SBarry Smith } PC_Redundant;
194b9ad928SBarry Smith 
204b9ad928SBarry Smith #undef __FUNCT__
214b9ad928SBarry Smith #define __FUNCT__ "PCView_Redundant"
226849ba73SBarry Smith static PetscErrorCode PCView_Redundant(PC pc,PetscViewer viewer)
234b9ad928SBarry Smith {
244b9ad928SBarry Smith   PC_Redundant   *red = (PC_Redundant*)pc->data;
25dfbe8321SBarry Smith   PetscErrorCode ierr;
26ace3abfcSBarry Smith   PetscBool      iascii,isstring;
2703ccd0b4SBarry Smith   PetscViewer    subviewer;
284b9ad928SBarry Smith 
294b9ad928SBarry Smith   PetscFunctionBegin;
30251f4c67SDmitry Karpeev   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr);
31251f4c67SDmitry Karpeev   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);CHKERRQ(ierr);
3232077d6dSBarry Smith   if (iascii) {
3303ccd0b4SBarry Smith     if (!red->psubcomm) {
3403ccd0b4SBarry Smith       ierr = PetscViewerASCIIPrintf(viewer,"  Redundant preconditioner: Not yet setup\n");CHKERRQ(ierr);
3503ccd0b4SBarry Smith     } else {
363e065800SHong Zhang       ierr = PetscViewerASCIIPrintf(viewer,"  Redundant preconditioner: First (color=0) of %D PCs follows\n",red->nsubcomm);CHKERRQ(ierr);
377adad957SLisandro Dalcin       ierr = PetscViewerGetSubcomm(viewer,((PetscObject)red->pc)->comm,&subviewer);CHKERRQ(ierr);
38f5dd71faSBarry Smith       if (!red->psubcomm->color) { /* only view first redundant pc */
394b9ad928SBarry Smith         ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
403e065800SHong Zhang         ierr = KSPView(red->ksp,subviewer);CHKERRQ(ierr);
414b9ad928SBarry Smith         ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
424b9ad928SBarry Smith       }
437adad957SLisandro Dalcin       ierr = PetscViewerRestoreSubcomm(viewer,((PetscObject)red->pc)->comm,&subviewer);CHKERRQ(ierr);
444b9ad928SBarry Smith     }
4503ccd0b4SBarry Smith   } else if (isstring) {
4603ccd0b4SBarry Smith     ierr = PetscViewerStringSPrintf(viewer," Redundant solver preconditioner");CHKERRQ(ierr);
474b9ad928SBarry Smith   }
484b9ad928SBarry Smith   PetscFunctionReturn(0);
494b9ad928SBarry Smith }
504b9ad928SBarry Smith 
51*d3b23db5SHong Zhang extern PetscErrorCode MatGetRedundantMatrix_MPIAIJ_interlaced(Mat,PetscInt,PetscSubcomm,MatReuse,Mat*); /* rm later! */
52*d3b23db5SHong Zhang 
534b9ad928SBarry Smith #undef __FUNCT__
544b9ad928SBarry Smith #define __FUNCT__ "PCSetUp_Redundant"
556849ba73SBarry Smith static PetscErrorCode PCSetUp_Redundant(PC pc)
564b9ad928SBarry Smith {
574b9ad928SBarry Smith   PC_Redundant   *red = (PC_Redundant*)pc->data;
58dfbe8321SBarry Smith   PetscErrorCode ierr;
5945fc02eaSBarry Smith   PetscInt       mstart,mend,mlocal,m,mlocal_sub,rstart_sub,rend_sub,mloc_sub;
6013f74950SBarry Smith   PetscMPIInt    size;
614b9ad928SBarry Smith   MatReuse       reuse = MAT_INITIAL_MATRIX;
624b9ad928SBarry Smith   MatStructure   str   = DIFFERENT_NONZERO_PATTERN;
63ce94432eSBarry Smith   MPI_Comm       comm,subcomm;
6423ce1328SBarry Smith   Vec            vec;
653f457be1SHong Zhang   PetscMPIInt    subsize,subrank;
661fbd8f88SHong Zhang   const char     *prefix;
67b862ddfaSBarry Smith   const PetscInt *range;
683f457be1SHong Zhang 
694b9ad928SBarry Smith   PetscFunctionBegin;
70ce94432eSBarry Smith   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
7123ce1328SBarry Smith   ierr = MatGetVecs(pc->pmat,&vec,0);CHKERRQ(ierr);
7223ce1328SBarry Smith   ierr = VecGetSize(vec,&m);CHKERRQ(ierr);
731fbd8f88SHong Zhang 
744b9ad928SBarry Smith   if (!pc->setupcalled) {
755f06b7aaSBarry Smith     if (!red->psubcomm) {
76d8a68f86SHong Zhang       ierr = PetscSubcommCreate(comm,&red->psubcomm);CHKERRQ(ierr);
77d8a68f86SHong Zhang       ierr = PetscSubcommSetNumber(red->psubcomm,red->nsubcomm);CHKERRQ(ierr);
78d8a68f86SHong Zhang       ierr = PetscSubcommSetType(red->psubcomm,PETSC_SUBCOMM_INTERLACED);CHKERRQ(ierr);
791fbd8f88SHong Zhang       ierr = PetscLogObjectMemory(pc,sizeof(PetscSubcomm));CHKERRQ(ierr);
801fbd8f88SHong Zhang 
811fbd8f88SHong Zhang       /* create a new PC that processors in each subcomm have copy of */
820d7810c8SBarry Smith       subcomm = red->psubcomm->comm;
832fa5cd67SKarl Rupp 
845f06b7aaSBarry Smith       ierr = KSPCreate(subcomm,&red->ksp);CHKERRQ(ierr);
855f06b7aaSBarry Smith       ierr = PetscObjectIncrementTabLevel((PetscObject)red->ksp,(PetscObject)pc,1);CHKERRQ(ierr);
865f06b7aaSBarry Smith       ierr = PetscLogObjectParent(pc,red->ksp);CHKERRQ(ierr);
875f06b7aaSBarry Smith       ierr = KSPSetType(red->ksp,KSPPREONLY);CHKERRQ(ierr);
885f06b7aaSBarry Smith       ierr = KSPGetPC(red->ksp,&red->pc);CHKERRQ(ierr);
89cf52b8b1SHong Zhang       ierr = PCSetType(red->pc,PCLU);CHKERRQ(ierr);
90cf52b8b1SHong Zhang 
911fbd8f88SHong Zhang       ierr = PCGetOptionsPrefix(pc,&prefix);CHKERRQ(ierr);
925f06b7aaSBarry Smith       ierr = KSPSetOptionsPrefix(red->ksp,prefix);CHKERRQ(ierr);
935f06b7aaSBarry Smith       ierr = KSPAppendOptionsPrefix(red->ksp,"redundant_");CHKERRQ(ierr);
942fa5cd67SKarl Rupp     } else subcomm = red->psubcomm->comm;
951fbd8f88SHong Zhang 
963f457be1SHong Zhang     /* create working vectors xsub/ysub and xdup/ydup */
9723ce1328SBarry Smith     ierr = VecGetLocalSize(vec,&mlocal);CHKERRQ(ierr);
983f457be1SHong Zhang     ierr = VecGetOwnershipRange(vec,&mstart,&mend);CHKERRQ(ierr);
994b9ad928SBarry Smith 
1003f457be1SHong Zhang     /* get local size of xsub/ysub */
1011fbd8f88SHong Zhang     ierr = MPI_Comm_size(subcomm,&subsize);CHKERRQ(ierr);
1021fbd8f88SHong Zhang     ierr = MPI_Comm_rank(subcomm,&subrank);CHKERRQ(ierr);
103b862ddfaSBarry Smith     ierr = MatGetOwnershipRanges(pc->pmat,&range);CHKERRQ(ierr);
104b862ddfaSBarry Smith     rstart_sub = range[red->psubcomm->n*subrank]; /* rstart in xsub/ysub */
1052fa5cd67SKarl Rupp     if (subrank+1 < subsize) rend_sub = range[red->psubcomm->n*(subrank+1)];
1062fa5cd67SKarl Rupp     else rend_sub = m;
1072fa5cd67SKarl Rupp 
1083f457be1SHong Zhang     mloc_sub = rend_sub - rstart_sub;
1091fbd8f88SHong Zhang     ierr     = VecCreateMPI(subcomm,mloc_sub,PETSC_DECIDE,&red->ysub);CHKERRQ(ierr);
1103f457be1SHong Zhang     /* create xsub with empty local arrays, because xdup's arrays will be placed into it */
1110298fd71SBarry Smith     ierr = VecCreateMPIWithArray(subcomm,1,mloc_sub,PETSC_DECIDE,NULL,&red->xsub);CHKERRQ(ierr);
1123f457be1SHong Zhang 
1133f457be1SHong Zhang     /* create xdup and ydup. ydup has empty local arrays because ysub's arrays will be place into it.
114ce94432eSBarry Smith        Note: we use communicator dupcomm, not PetscObjectComm((PetscObject)pc)! */
1151fbd8f88SHong Zhang     ierr = VecCreateMPI(red->psubcomm->dupparent,mloc_sub,PETSC_DECIDE,&red->xdup);CHKERRQ(ierr);
1160298fd71SBarry Smith     ierr = VecCreateMPIWithArray(red->psubcomm->dupparent,1,mloc_sub,PETSC_DECIDE,NULL,&red->ydup);CHKERRQ(ierr);
1173f457be1SHong Zhang 
1183f457be1SHong Zhang     /* create vec scatters */
1193f457be1SHong Zhang     if (!red->scatterin) {
1203f457be1SHong Zhang       IS       is1,is2;
1213f457be1SHong Zhang       PetscInt *idx1,*idx2,i,j,k;
12245fc02eaSBarry Smith 
1231d79065fSBarry Smith       ierr = PetscMalloc2(red->psubcomm->n*mlocal,PetscInt,&idx1,red->psubcomm->n*mlocal,PetscInt,&idx2);CHKERRQ(ierr);
1243f457be1SHong Zhang       j    = 0;
1251fbd8f88SHong Zhang       for (k=0; k<red->psubcomm->n; k++) {
1263f457be1SHong Zhang         for (i=mstart; i<mend; i++) {
1273f457be1SHong Zhang           idx1[j]   = i;
1283f457be1SHong Zhang           idx2[j++] = i + m*k;
1293f457be1SHong Zhang         }
1303f457be1SHong Zhang       }
13170b3c8c7SBarry Smith       ierr = ISCreateGeneral(comm,red->psubcomm->n*mlocal,idx1,PETSC_COPY_VALUES,&is1);CHKERRQ(ierr);
13270b3c8c7SBarry Smith       ierr = ISCreateGeneral(comm,red->psubcomm->n*mlocal,idx2,PETSC_COPY_VALUES,&is2);CHKERRQ(ierr);
1333f457be1SHong Zhang       ierr = VecScatterCreate(vec,is1,red->xdup,is2,&red->scatterin);CHKERRQ(ierr);
134fcfd50ebSBarry Smith       ierr = ISDestroy(&is1);CHKERRQ(ierr);
135fcfd50ebSBarry Smith       ierr = ISDestroy(&is2);CHKERRQ(ierr);
1363f457be1SHong Zhang 
1371fbd8f88SHong Zhang       ierr = ISCreateStride(comm,mlocal,mstart+ red->psubcomm->color*m,1,&is1);CHKERRQ(ierr);
1383f457be1SHong Zhang       ierr = ISCreateStride(comm,mlocal,mstart,1,&is2);CHKERRQ(ierr);
1393f457be1SHong Zhang       ierr = VecScatterCreate(red->xdup,is1,vec,is2,&red->scatterout);CHKERRQ(ierr);
140fcfd50ebSBarry Smith       ierr = ISDestroy(&is1);CHKERRQ(ierr);
141fcfd50ebSBarry Smith       ierr = ISDestroy(&is2);CHKERRQ(ierr);
1421d79065fSBarry Smith       ierr = PetscFree2(idx1,idx2);CHKERRQ(ierr);
1434b9ad928SBarry Smith     }
1444b9ad928SBarry Smith   }
1456bf464f9SBarry Smith   ierr = VecDestroy(&vec);CHKERRQ(ierr);
1464b9ad928SBarry Smith 
1474b9ad928SBarry Smith   /* if pmatrix set by user is sequential then we do not need to gather the parallel matrix */
1483f457be1SHong Zhang   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
1492fa5cd67SKarl Rupp   if (size == 1) red->useparallelmat = PETSC_FALSE;
1504b9ad928SBarry Smith 
1514b9ad928SBarry Smith   if (red->useparallelmat) {
1524b9ad928SBarry Smith     if (pc->setupcalled == 1 && pc->flag == DIFFERENT_NONZERO_PATTERN) {
1534b9ad928SBarry Smith       /* destroy old matrices */
1546bf464f9SBarry Smith       ierr = MatDestroy(&red->pmats);CHKERRQ(ierr);
1554b9ad928SBarry Smith     } else if (pc->setupcalled == 1) {
1564b9ad928SBarry Smith       reuse = MAT_REUSE_MATRIX;
1574b9ad928SBarry Smith       str   = SAME_NONZERO_PATTERN;
1584b9ad928SBarry Smith     }
1594b9ad928SBarry Smith 
1603f457be1SHong Zhang     /* grab the parallel matrix and put it into processors of a subcomminicator */
161f664ae05SHong Zhang     /*--------------------------------------------------------------------------*/
162f664ae05SHong Zhang     ierr = VecGetLocalSize(red->ysub,&mlocal_sub);CHKERRQ(ierr);
163*d3b23db5SHong Zhang     ierr = MatGetRedundantMatrix_MPIAIJ_interlaced(pc->pmat,red->psubcomm->n,red->psubcomm,reuse,&red->pmats);CHKERRQ(ierr);
1643f457be1SHong Zhang     /* tell PC of the subcommunicator its operators */
16590f1c854SHong Zhang     ierr = KSPSetOperators(red->ksp,red->pmats,red->pmats,str);CHKERRQ(ierr);
1664b9ad928SBarry Smith   } else {
16790f1c854SHong Zhang     ierr = KSPSetOperators(red->ksp,pc->mat,pc->pmat,pc->flag);CHKERRQ(ierr);
1684b9ad928SBarry Smith   }
1690c24e6a1SHong Zhang   if (pc->setfromoptionscalled) {
1703e065800SHong Zhang     ierr = KSPSetFromOptions(red->ksp);CHKERRQ(ierr);
1710c24e6a1SHong Zhang   }
1723e065800SHong Zhang   ierr = KSPSetUp(red->ksp);CHKERRQ(ierr);
1734b9ad928SBarry Smith   PetscFunctionReturn(0);
1744b9ad928SBarry Smith }
1754b9ad928SBarry Smith 
1764b9ad928SBarry Smith #undef __FUNCT__
1774b9ad928SBarry Smith #define __FUNCT__ "PCApply_Redundant"
1786849ba73SBarry Smith static PetscErrorCode PCApply_Redundant(PC pc,Vec x,Vec y)
1794b9ad928SBarry Smith {
1804b9ad928SBarry Smith   PC_Redundant   *red = (PC_Redundant*)pc->data;
181dfbe8321SBarry Smith   PetscErrorCode ierr;
1823f457be1SHong Zhang   PetscScalar    *array;
1834b9ad928SBarry Smith 
1844b9ad928SBarry Smith   PetscFunctionBegin;
1853f457be1SHong Zhang   /* scatter x to xdup */
186ca9f406cSSatish Balay   ierr = VecScatterBegin(red->scatterin,x,red->xdup,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
187ca9f406cSSatish Balay   ierr = VecScatterEnd(red->scatterin,x,red->xdup,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1883f457be1SHong Zhang 
1893f457be1SHong Zhang   /* place xdup's local array into xsub */
1903f457be1SHong Zhang   ierr = VecGetArray(red->xdup,&array);CHKERRQ(ierr);
1913f457be1SHong Zhang   ierr = VecPlaceArray(red->xsub,(const PetscScalar*)array);CHKERRQ(ierr);
1924b9ad928SBarry Smith 
1934b9ad928SBarry Smith   /* apply preconditioner on each processor */
19483ab6a24SBarry Smith   ierr = KSPSolve(red->ksp,red->xsub,red->ysub);CHKERRQ(ierr);
1953f457be1SHong Zhang   ierr = VecResetArray(red->xsub);CHKERRQ(ierr);
1963f457be1SHong Zhang   ierr = VecRestoreArray(red->xdup,&array);CHKERRQ(ierr);
1974b9ad928SBarry Smith 
1983f457be1SHong Zhang   /* place ysub's local array into ydup */
1993f457be1SHong Zhang   ierr = VecGetArray(red->ysub,&array);CHKERRQ(ierr);
2003f457be1SHong Zhang   ierr = VecPlaceArray(red->ydup,(const PetscScalar*)array);CHKERRQ(ierr);
2013f457be1SHong Zhang 
2023f457be1SHong Zhang   /* scatter ydup to y */
203ca9f406cSSatish Balay   ierr = VecScatterBegin(red->scatterout,red->ydup,y,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
204ca9f406cSSatish Balay   ierr = VecScatterEnd(red->scatterout,red->ydup,y,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
2053f457be1SHong Zhang   ierr = VecResetArray(red->ydup);CHKERRQ(ierr);
2063f457be1SHong Zhang   ierr = VecRestoreArray(red->ysub,&array);CHKERRQ(ierr);
2074b9ad928SBarry Smith   PetscFunctionReturn(0);
2084b9ad928SBarry Smith }
2094b9ad928SBarry Smith 
2104b9ad928SBarry Smith #undef __FUNCT__
2111ea5a559SBarry Smith #define __FUNCT__ "PCReset_Redundant"
2121ea5a559SBarry Smith static PetscErrorCode PCReset_Redundant(PC pc)
2134b9ad928SBarry Smith {
2144b9ad928SBarry Smith   PC_Redundant   *red = (PC_Redundant*)pc->data;
215dfbe8321SBarry Smith   PetscErrorCode ierr;
2164b9ad928SBarry Smith 
2174b9ad928SBarry Smith   PetscFunctionBegin;
2186bf464f9SBarry Smith   ierr = VecScatterDestroy(&red->scatterin);CHKERRQ(ierr);
2196bf464f9SBarry Smith   ierr = VecScatterDestroy(&red->scatterout);CHKERRQ(ierr);
2206bf464f9SBarry Smith   ierr = VecDestroy(&red->ysub);CHKERRQ(ierr);
2216bf464f9SBarry Smith   ierr = VecDestroy(&red->xsub);CHKERRQ(ierr);
2226bf464f9SBarry Smith   ierr = VecDestroy(&red->xdup);CHKERRQ(ierr);
2236bf464f9SBarry Smith   ierr = VecDestroy(&red->ydup);CHKERRQ(ierr);
2246bf464f9SBarry Smith   ierr = MatDestroy(&red->pmats);CHKERRQ(ierr);
225546c30cbSLisandro Dalcin   if (red->ksp) {ierr = KSPReset(red->ksp);CHKERRQ(ierr);}
2261ea5a559SBarry Smith   PetscFunctionReturn(0);
2271ea5a559SBarry Smith }
2281ea5a559SBarry Smith 
2291ea5a559SBarry Smith #undef __FUNCT__
2301ea5a559SBarry Smith #define __FUNCT__ "PCDestroy_Redundant"
2311ea5a559SBarry Smith static PetscErrorCode PCDestroy_Redundant(PC pc)
2321ea5a559SBarry Smith {
2331ea5a559SBarry Smith   PC_Redundant   *red = (PC_Redundant*)pc->data;
2341ea5a559SBarry Smith   PetscErrorCode ierr;
2351ea5a559SBarry Smith 
2361ea5a559SBarry Smith   PetscFunctionBegin;
2371ea5a559SBarry Smith   ierr = PCReset_Redundant(pc);CHKERRQ(ierr);
2386bf464f9SBarry Smith   ierr = KSPDestroy(&red->ksp);CHKERRQ(ierr);
2396bf464f9SBarry Smith   ierr = PetscSubcommDestroy(&red->psubcomm);CHKERRQ(ierr);
240c31cb41cSBarry Smith   ierr = PetscFree(pc->data);CHKERRQ(ierr);
2414b9ad928SBarry Smith   PetscFunctionReturn(0);
2424b9ad928SBarry Smith }
2434b9ad928SBarry Smith 
2444b9ad928SBarry Smith #undef __FUNCT__
2454b9ad928SBarry Smith #define __FUNCT__ "PCSetFromOptions_Redundant"
2466849ba73SBarry Smith static PetscErrorCode PCSetFromOptions_Redundant(PC pc)
2474b9ad928SBarry Smith {
248a98ce0f4SHong Zhang   PetscErrorCode ierr;
249a98ce0f4SHong Zhang   PC_Redundant   *red = (PC_Redundant*)pc->data;
250a98ce0f4SHong Zhang 
2514b9ad928SBarry Smith   PetscFunctionBegin;
252a98ce0f4SHong Zhang   ierr = PetscOptionsHead("Redundant options");CHKERRQ(ierr);
25309a6bc64SHong Zhang   ierr = PetscOptionsInt("-pc_redundant_number","Number of redundant pc","PCRedundantSetNumber",red->nsubcomm,&red->nsubcomm,0);CHKERRQ(ierr);
254a98ce0f4SHong Zhang   ierr = PetscOptionsTail();CHKERRQ(ierr);
2554b9ad928SBarry Smith   PetscFunctionReturn(0);
2564b9ad928SBarry Smith }
2574b9ad928SBarry Smith 
2584b9ad928SBarry Smith #undef __FUNCT__
25909a6bc64SHong Zhang #define __FUNCT__ "PCRedundantSetNumber_Redundant"
260f7a08781SBarry Smith static PetscErrorCode  PCRedundantSetNumber_Redundant(PC pc,PetscInt nreds)
26109a6bc64SHong Zhang {
26209a6bc64SHong Zhang   PC_Redundant *red = (PC_Redundant*)pc->data;
26309a6bc64SHong Zhang 
26409a6bc64SHong Zhang   PetscFunctionBegin;
26509a6bc64SHong Zhang   red->nsubcomm = nreds;
26609a6bc64SHong Zhang   PetscFunctionReturn(0);
26709a6bc64SHong Zhang }
26809a6bc64SHong Zhang 
26909a6bc64SHong Zhang #undef __FUNCT__
27009a6bc64SHong Zhang #define __FUNCT__ "PCRedundantSetNumber"
27109a6bc64SHong Zhang /*@
27209a6bc64SHong Zhang    PCRedundantSetNumber - Sets the number of redundant preconditioner contexts.
27309a6bc64SHong Zhang 
2743f9fe445SBarry Smith    Logically Collective on PC
27509a6bc64SHong Zhang 
27609a6bc64SHong Zhang    Input Parameters:
27709a6bc64SHong Zhang +  pc - the preconditioner context
2789b21d695SBarry Smith -  nredundant - number of redundant preconditioner contexts; for example if you are using 64 MPI processes and
2799b21d695SBarry Smith                               use an nredundant of 4 there will be 4 parallel solves each on 16 = 64/4 processes.
28009a6bc64SHong Zhang 
28109a6bc64SHong Zhang    Level: advanced
28209a6bc64SHong Zhang 
28309a6bc64SHong Zhang .keywords: PC, redundant solve
28409a6bc64SHong Zhang @*/
2857087cfbeSBarry Smith PetscErrorCode  PCRedundantSetNumber(PC pc,PetscInt nredundant)
28609a6bc64SHong Zhang {
2874ac538c5SBarry Smith   PetscErrorCode ierr;
28809a6bc64SHong Zhang 
28909a6bc64SHong Zhang   PetscFunctionBegin;
2900700a824SBarry Smith   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
291ce94432eSBarry Smith   if (nredundant <= 0) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONG, "num of redundant pc %D must be positive",nredundant);
2924ac538c5SBarry Smith   ierr = PetscTryMethod(pc,"PCRedundantSetNumber_C",(PC,PetscInt),(pc,nredundant));CHKERRQ(ierr);
29309a6bc64SHong Zhang   PetscFunctionReturn(0);
29409a6bc64SHong Zhang }
29509a6bc64SHong Zhang 
29609a6bc64SHong Zhang #undef __FUNCT__
2974b9ad928SBarry Smith #define __FUNCT__ "PCRedundantSetScatter_Redundant"
298f7a08781SBarry Smith static PetscErrorCode  PCRedundantSetScatter_Redundant(PC pc,VecScatter in,VecScatter out)
2994b9ad928SBarry Smith {
3004b9ad928SBarry Smith   PC_Redundant   *red = (PC_Redundant*)pc->data;
301dfbe8321SBarry Smith   PetscErrorCode ierr;
3024b9ad928SBarry Smith 
3034b9ad928SBarry Smith   PetscFunctionBegin;
3044b9ad928SBarry Smith   ierr = PetscObjectReference((PetscObject)in);CHKERRQ(ierr);
3056bf464f9SBarry Smith   ierr = VecScatterDestroy(&red->scatterin);CHKERRQ(ierr);
3062fa5cd67SKarl Rupp 
307c3122656SLisandro Dalcin   red->scatterin  = in;
3082fa5cd67SKarl Rupp 
3094b9ad928SBarry Smith   ierr = PetscObjectReference((PetscObject)out);CHKERRQ(ierr);
3106bf464f9SBarry Smith   ierr = VecScatterDestroy(&red->scatterout);CHKERRQ(ierr);
311c3122656SLisandro Dalcin   red->scatterout = out;
3124b9ad928SBarry Smith   PetscFunctionReturn(0);
3134b9ad928SBarry Smith }
3144b9ad928SBarry Smith 
3154b9ad928SBarry Smith #undef __FUNCT__
3164b9ad928SBarry Smith #define __FUNCT__ "PCRedundantSetScatter"
3174b9ad928SBarry Smith /*@
3184b9ad928SBarry Smith    PCRedundantSetScatter - Sets the scatter used to copy values into the
3194b9ad928SBarry Smith      redundant local solve and the scatter to move them back into the global
3204b9ad928SBarry Smith      vector.
3214b9ad928SBarry Smith 
3223f9fe445SBarry Smith    Logically Collective on PC
3234b9ad928SBarry Smith 
3244b9ad928SBarry Smith    Input Parameters:
3254b9ad928SBarry Smith +  pc - the preconditioner context
3264b9ad928SBarry Smith .  in - the scatter to move the values in
3274b9ad928SBarry Smith -  out - the scatter to move them out
3284b9ad928SBarry Smith 
3294b9ad928SBarry Smith    Level: advanced
3304b9ad928SBarry Smith 
3314b9ad928SBarry Smith .keywords: PC, redundant solve
3324b9ad928SBarry Smith @*/
3337087cfbeSBarry Smith PetscErrorCode  PCRedundantSetScatter(PC pc,VecScatter in,VecScatter out)
3344b9ad928SBarry Smith {
3354ac538c5SBarry Smith   PetscErrorCode ierr;
3364b9ad928SBarry Smith 
3374b9ad928SBarry Smith   PetscFunctionBegin;
3380700a824SBarry Smith   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
3390700a824SBarry Smith   PetscValidHeaderSpecific(in,VEC_SCATTER_CLASSID,2);
3400700a824SBarry Smith   PetscValidHeaderSpecific(out,VEC_SCATTER_CLASSID,3);
3414ac538c5SBarry Smith   ierr = PetscTryMethod(pc,"PCRedundantSetScatter_C",(PC,VecScatter,VecScatter),(pc,in,out));CHKERRQ(ierr);
3424b9ad928SBarry Smith   PetscFunctionReturn(0);
3434b9ad928SBarry Smith }
3444b9ad928SBarry Smith 
3454b9ad928SBarry Smith #undef __FUNCT__
34683ab6a24SBarry Smith #define __FUNCT__ "PCRedundantGetKSP_Redundant"
347f7a08781SBarry Smith static PetscErrorCode  PCRedundantGetKSP_Redundant(PC pc,KSP *innerksp)
3484b9ad928SBarry Smith {
3495f06b7aaSBarry Smith   PetscErrorCode ierr;
3504b9ad928SBarry Smith   PC_Redundant   *red = (PC_Redundant*)pc->data;
3515f06b7aaSBarry Smith   MPI_Comm       comm,subcomm;
3525f06b7aaSBarry Smith   const char     *prefix;
3534b9ad928SBarry Smith 
3544b9ad928SBarry Smith   PetscFunctionBegin;
3555f06b7aaSBarry Smith   if (!red->psubcomm) {
3565f06b7aaSBarry Smith     ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
357d8a68f86SHong Zhang     ierr = PetscSubcommCreate(comm,&red->psubcomm);CHKERRQ(ierr);
358d8a68f86SHong Zhang     ierr = PetscSubcommSetNumber(red->psubcomm,red->nsubcomm);CHKERRQ(ierr);
359d8a68f86SHong Zhang     ierr = PetscSubcommSetType(red->psubcomm,PETSC_SUBCOMM_INTERLACED);CHKERRQ(ierr);
3605f06b7aaSBarry Smith     ierr = PetscLogObjectMemory(pc,sizeof(PetscSubcomm));CHKERRQ(ierr);
3615f06b7aaSBarry Smith 
3625f06b7aaSBarry Smith     /* create a new PC that processors in each subcomm have copy of */
3635f06b7aaSBarry Smith     subcomm = red->psubcomm->comm;
3642fa5cd67SKarl Rupp 
3655f06b7aaSBarry Smith     ierr = KSPCreate(subcomm,&red->ksp);CHKERRQ(ierr);
3665f06b7aaSBarry Smith     ierr = PetscObjectIncrementTabLevel((PetscObject)red->ksp,(PetscObject)pc,1);CHKERRQ(ierr);
3675f06b7aaSBarry Smith     ierr = PetscLogObjectParent(pc,red->ksp);CHKERRQ(ierr);
3685f06b7aaSBarry Smith     ierr = KSPSetType(red->ksp,KSPPREONLY);CHKERRQ(ierr);
3695f06b7aaSBarry Smith     ierr = KSPGetPC(red->ksp,&red->pc);CHKERRQ(ierr);
3705f06b7aaSBarry Smith     ierr = PCSetType(red->pc,PCLU);CHKERRQ(ierr);
3715f06b7aaSBarry Smith 
3725f06b7aaSBarry Smith     ierr = PCGetOptionsPrefix(pc,&prefix);CHKERRQ(ierr);
3735f06b7aaSBarry Smith     ierr = KSPSetOptionsPrefix(red->ksp,prefix);CHKERRQ(ierr);
3745f06b7aaSBarry Smith     ierr = KSPAppendOptionsPrefix(red->ksp,"redundant_");CHKERRQ(ierr);
3755f06b7aaSBarry Smith   }
37683ab6a24SBarry Smith   *innerksp = red->ksp;
3774b9ad928SBarry Smith   PetscFunctionReturn(0);
3784b9ad928SBarry Smith }
3794b9ad928SBarry Smith 
3804b9ad928SBarry Smith #undef __FUNCT__
38183ab6a24SBarry Smith #define __FUNCT__ "PCRedundantGetKSP"
3824b9ad928SBarry Smith /*@
38383ab6a24SBarry Smith    PCRedundantGetKSP - Gets the less parallel KSP created by the redundant PC.
3844b9ad928SBarry Smith 
3854b9ad928SBarry Smith    Not Collective
3864b9ad928SBarry Smith 
3874b9ad928SBarry Smith    Input Parameter:
3884b9ad928SBarry Smith .  pc - the preconditioner context
3894b9ad928SBarry Smith 
3904b9ad928SBarry Smith    Output Parameter:
39183ab6a24SBarry Smith .  innerksp - the KSP on the smaller set of processes
3924b9ad928SBarry Smith 
3934b9ad928SBarry Smith    Level: advanced
3944b9ad928SBarry Smith 
3954b9ad928SBarry Smith .keywords: PC, redundant solve
3964b9ad928SBarry Smith @*/
39783ab6a24SBarry Smith PetscErrorCode  PCRedundantGetKSP(PC pc,KSP *innerksp)
3984b9ad928SBarry Smith {
3994ac538c5SBarry Smith   PetscErrorCode ierr;
4004b9ad928SBarry Smith 
4014b9ad928SBarry Smith   PetscFunctionBegin;
4020700a824SBarry Smith   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
40383ab6a24SBarry Smith   PetscValidPointer(innerksp,2);
40483ab6a24SBarry Smith   ierr = PetscTryMethod(pc,"PCRedundantGetKSP_C",(PC,KSP*),(pc,innerksp));CHKERRQ(ierr);
4054b9ad928SBarry Smith   PetscFunctionReturn(0);
4064b9ad928SBarry Smith }
4074b9ad928SBarry Smith 
4084b9ad928SBarry Smith #undef __FUNCT__
4094b9ad928SBarry Smith #define __FUNCT__ "PCRedundantGetOperators_Redundant"
410f7a08781SBarry Smith static PetscErrorCode  PCRedundantGetOperators_Redundant(PC pc,Mat *mat,Mat *pmat)
4114b9ad928SBarry Smith {
4124b9ad928SBarry Smith   PC_Redundant *red = (PC_Redundant*)pc->data;
4134b9ad928SBarry Smith 
4144b9ad928SBarry Smith   PetscFunctionBegin;
415b3804887SHong Zhang   if (mat)  *mat  = red->pmats;
416b3804887SHong Zhang   if (pmat) *pmat = red->pmats;
4174b9ad928SBarry Smith   PetscFunctionReturn(0);
4184b9ad928SBarry Smith }
4194b9ad928SBarry Smith 
4204b9ad928SBarry Smith #undef __FUNCT__
4214b9ad928SBarry Smith #define __FUNCT__ "PCRedundantGetOperators"
4224b9ad928SBarry Smith /*@
4234b9ad928SBarry Smith    PCRedundantGetOperators - gets the sequential matrix and preconditioner matrix
4244b9ad928SBarry Smith 
4254b9ad928SBarry Smith    Not Collective
4264b9ad928SBarry Smith 
4274b9ad928SBarry Smith    Input Parameter:
4284b9ad928SBarry Smith .  pc - the preconditioner context
4294b9ad928SBarry Smith 
4304b9ad928SBarry Smith    Output Parameters:
4314b9ad928SBarry Smith +  mat - the matrix
4324b9ad928SBarry Smith -  pmat - the (possibly different) preconditioner matrix
4334b9ad928SBarry Smith 
4344b9ad928SBarry Smith    Level: advanced
4354b9ad928SBarry Smith 
4364b9ad928SBarry Smith .keywords: PC, redundant solve
4374b9ad928SBarry Smith @*/
4387087cfbeSBarry Smith PetscErrorCode  PCRedundantGetOperators(PC pc,Mat *mat,Mat *pmat)
4394b9ad928SBarry Smith {
4404ac538c5SBarry Smith   PetscErrorCode ierr;
4414b9ad928SBarry Smith 
4424b9ad928SBarry Smith   PetscFunctionBegin;
4430700a824SBarry Smith   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
4444482741eSBarry Smith   if (mat)  PetscValidPointer(mat,2);
4454482741eSBarry Smith   if (pmat) PetscValidPointer(pmat,3);
4464ac538c5SBarry Smith   ierr = PetscTryMethod(pc,"PCRedundantGetOperators_C",(PC,Mat*,Mat*),(pc,mat,pmat));CHKERRQ(ierr);
4474b9ad928SBarry Smith   PetscFunctionReturn(0);
4484b9ad928SBarry Smith }
4494b9ad928SBarry Smith 
4504b9ad928SBarry Smith /* -------------------------------------------------------------------------------------*/
45137a17b4dSBarry Smith /*MC
45283ab6a24SBarry Smith      PCREDUNDANT - Runs a KSP solver with preconditioner for the entire problem on subgroups of processors
45337a17b4dSBarry Smith 
45483ab6a24SBarry Smith      Options for the redundant preconditioners can be set with -redundant_pc_xxx for the redundant KSP with -redundant_ksp_xxx
45537a17b4dSBarry Smith 
45609391456SBarry Smith   Options Database:
4579b21d695SBarry Smith .  -pc_redundant_number <n> - number of redundant solves, for example if you are using 64 MPI processes and
4589b21d695SBarry Smith                               use an n of 4 there will be 4 parallel solves each on 16 = 64/4 processes.
45909391456SBarry Smith 
46037a17b4dSBarry Smith    Level: intermediate
46137a17b4dSBarry Smith 
46283ab6a24SBarry Smith    Notes: The default KSP is preonly and the default PC is LU.
46383ab6a24SBarry Smith 
46483ab6a24SBarry Smith    Developer Notes: Note that PCSetInitialGuessNonzero()  is not used by this class but likely should be.
4659cfaa89bSBarry Smith 
46637a17b4dSBarry Smith .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PCRedundantSetScatter(),
46783ab6a24SBarry Smith            PCRedundantGetKSP(), PCRedundantGetOperators(), PCRedundantSetNumber()
46837a17b4dSBarry Smith M*/
46937a17b4dSBarry Smith 
4704b9ad928SBarry Smith #undef __FUNCT__
4714b9ad928SBarry Smith #define __FUNCT__ "PCCreate_Redundant"
4728cc058d9SJed Brown PETSC_EXTERN PetscErrorCode PCCreate_Redundant(PC pc)
4734b9ad928SBarry Smith {
474dfbe8321SBarry Smith   PetscErrorCode ierr;
4754b9ad928SBarry Smith   PC_Redundant   *red;
47669db28dcSHong Zhang   PetscMPIInt    size;
4773f457be1SHong Zhang 
4784b9ad928SBarry Smith   PetscFunctionBegin;
47938f2d2fdSLisandro Dalcin   ierr = PetscNewLog(pc,PC_Redundant,&red);CHKERRQ(ierr);
480ce94432eSBarry Smith   ierr = MPI_Comm_size(PetscObjectComm((PetscObject)pc),&size);CHKERRQ(ierr);
4812fa5cd67SKarl Rupp 
48269db28dcSHong Zhang   red->nsubcomm       = size;
4834b9ad928SBarry Smith   red->useparallelmat = PETSC_TRUE;
4841fbd8f88SHong Zhang   pc->data            = (void*)red;
4854b9ad928SBarry Smith 
4864b9ad928SBarry Smith   pc->ops->apply          = PCApply_Redundant;
4874b9ad928SBarry Smith   pc->ops->applytranspose = 0;
4884b9ad928SBarry Smith   pc->ops->setup          = PCSetUp_Redundant;
4894b9ad928SBarry Smith   pc->ops->destroy        = PCDestroy_Redundant;
4901ea5a559SBarry Smith   pc->ops->reset          = PCReset_Redundant;
4914b9ad928SBarry Smith   pc->ops->setfromoptions = PCSetFromOptions_Redundant;
4924b9ad928SBarry Smith   pc->ops->view           = PCView_Redundant;
4932fa5cd67SKarl Rupp 
494bdf89e91SBarry Smith   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCRedundantSetScatter_C",PCRedundantSetScatter_Redundant);CHKERRQ(ierr);
495bdf89e91SBarry Smith   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCRedundantSetNumber_C",PCRedundantSetNumber_Redundant);CHKERRQ(ierr);
496bdf89e91SBarry Smith   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCRedundantGetKSP_C",PCRedundantGetKSP_Redundant);CHKERRQ(ierr);
497bdf89e91SBarry Smith   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCRedundantGetOperators_C",PCRedundantGetOperators_Redundant);CHKERRQ(ierr);
4984b9ad928SBarry Smith   PetscFunctionReturn(0);
4994b9ad928SBarry Smith }
500b2573a8aSBarry Smith 
501