int main(int argc,char **argv)
{
PetscErrorCode ierr;
PetscViewer viewer,subviewer,subsubviewer;
PetscViewerFormat format;
PetscBool flg;
PetscSubcomm psubcomm,psubsubcomm;
MPI_Comm comm,subcomm,subsubcomm;
PetscMPIInt size;
/*
Every PETSc routine should begin with the PetscInitialize() routine.
argc, argv - These command line arguments are taken to extract the options
supplied to PETSc and options supplied to MPI.
help - When PETSc executable is invoked with the option -help,
it prints the various options that can be applied at
runtime. The user can use the "help" variable place
additional help messages in this printout.
*/
ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
comm = PETSC_COMM_WORLD;
ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
if (size < 4) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Must run with at least 4 MPI processes");
ierr = PetscOptionsGetViewer(comm,NULL,"-viewer",&viewer,&format,&flg);CHKERRQ(ierr);
if (!viewer) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Must use -viewer option");
ierr = PetscViewerASCIIPrintf(viewer,"Print called on original full viewer %d\n",PetscGlobalRank);CHKERRQ(ierr);
ierr = PetscSubcommCreate(comm,&psubcomm);CHKERRQ(ierr);
ierr = PetscSubcommSetNumber(psubcomm,2);CHKERRQ(ierr);
ierr = PetscSubcommSetType(psubcomm,PETSC_SUBCOMM_CONTIGUOUS);CHKERRQ(ierr);
/* enable runtime switch of psubcomm type, e.g., '-psubcomm_type interlaced */
ierr = PetscSubcommSetFromOptions(psubcomm);CHKERRQ(ierr);
subcomm = PetscSubcommChild(psubcomm);
ierr = PetscViewerGetSubViewer(viewer,subcomm,&subviewer);CHKERRQ(ierr);
ierr = PetscViewerASCIIPrintf(subviewer," Print called on sub viewers %d\n",PetscGlobalRank);CHKERRQ(ierr);
ierr = PetscSubcommCreate(subcomm,&psubsubcomm);CHKERRQ(ierr);
ierr = PetscSubcommSetNumber(psubsubcomm,2);CHKERRQ(ierr);
ierr = PetscSubcommSetType(psubsubcomm,PETSC_SUBCOMM_CONTIGUOUS);CHKERRQ(ierr);
/* enable runtime switch of psubcomm type, e.g., '-psubcomm_type interlaced */
ierr = PetscSubcommSetFromOptions(psubsubcomm);CHKERRQ(ierr);
subsubcomm = PetscSubcommChild(psubsubcomm);
ierr = PetscViewerGetSubViewer(subviewer,subsubcomm,&subsubviewer);CHKERRQ(ierr);
ierr = PetscViewerASCIIPrintf(subsubviewer," Print called on sub sub viewers %d\n",PetscGlobalRank);CHKERRQ(ierr);
ierr = PetscViewerRestoreSubViewer(subviewer,subsubcomm,&subsubviewer);CHKERRQ(ierr);
ierr = PetscViewerRestoreSubViewer(viewer,subcomm,&subviewer);CHKERRQ(ierr);
ierr = PetscSubcommDestroy(&psubsubcomm);CHKERRQ(ierr);
ierr = PetscSubcommDestroy(&psubcomm);CHKERRQ(ierr);
ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
ierr = PetscFinalize();
return ierr;
}
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);
}
int main(int argc,char **args)
{
Mat A,Ar,C;
PetscViewer fd; /* viewer */
char file[PETSC_MAX_PATH_LEN]; /* input file name */
PetscErrorCode ierr;
PetscInt ns=2,np;
PetscSubcomm subc;
PetscBool flg;
PetscInitialize(&argc,&args,(char*)0,help);
/*
Determine files from which we read the two linear systems
(matrix and right-hand-side vector).
*/
ierr = PetscOptionsGetString(NULL,"-f0",file,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
if (!flg) SETERRQ(PETSC_COMM_WORLD,1,"Must indicate binary file with the -f0 option");
ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,file,FILE_MODE_READ,&fd);CHKERRQ(ierr);
ierr = MPI_Comm_size(PETSC_COMM_WORLD,&np);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD,"Reading matrix with %d processors\n",np);CHKERRQ(ierr);
ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr);
ierr = MatLoad(A,fd);CHKERRQ(ierr);
ierr = PetscViewerDestroy(&fd);CHKERRQ(ierr);
/*
Determines amount of subcomunicators
*/
ierr = PetscOptionsGetInt(NULL,"-nsub",&ns,NULL);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD,"Splitting in %d subcommunicators\n",ns);CHKERRQ(ierr);
ierr = PetscSubcommCreate(PetscObjectComm((PetscObject)A),&subc);CHKERRQ(ierr);
ierr = PetscSubcommSetNumber(subc,ns);CHKERRQ(ierr);
ierr = PetscSubcommSetType(subc,PETSC_SUBCOMM_CONTIGUOUS);CHKERRQ(ierr);
ierr = PetscSubcommSetFromOptions(subc);CHKERRQ(ierr);
ierr = MatCreateRedundantMatrix(A,0,PetscSubcommChild(subc),MAT_INITIAL_MATRIX,&Ar);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD,"Copying matrix\n",ns);CHKERRQ(ierr);
ierr = MatDuplicate(Ar,MAT_COPY_VALUES,&C);CHKERRQ(ierr);
ierr = PetscSubcommDestroy(&subc);CHKERRQ(ierr);
/*
Free memory
*/
ierr = MatDestroy(&A);CHKERRQ(ierr);
ierr = MatDestroy(&Ar);CHKERRQ(ierr);
ierr = MatDestroy(&C);CHKERRQ(ierr);
ierr = PetscFinalize();
return 0;
}
static PetscErrorCode PCSetUp_Redundant(PC pc)
{
PC_Redundant *red = (PC_Redundant*)pc->data;
PetscErrorCode ierr;
PetscInt mstart,mend,mlocal,M;
PetscMPIInt size;
MPI_Comm comm,subcomm;
Vec x;
const char *prefix;
PetscFunctionBegin;
ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
/* if pmatrix set by user is sequential then we do not need to gather the parallel matrix */
ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
if (size == 1) red->useparallelmat = PETSC_FALSE;
if (!pc->setupcalled) {
PetscInt mloc_sub;
if (!red->psubcomm) {
ierr = PetscSubcommCreate(comm,&red->psubcomm);CHKERRQ(ierr);
ierr = PetscSubcommSetNumber(red->psubcomm,red->nsubcomm);CHKERRQ(ierr);
ierr = PetscSubcommSetType(red->psubcomm,PETSC_SUBCOMM_CONTIGUOUS);CHKERRQ(ierr);
/* enable runtime switch of psubcomm type, e.g., '-psubcomm_type interlaced */
ierr = PetscSubcommSetFromOptions(red->psubcomm);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);
} else {
subcomm = PetscSubcommChild(red->psubcomm);
}
if (red->useparallelmat) {
/* grab the parallel matrix and put it into processors of a subcomminicator */
ierr = MatCreateRedundantMatrix(pc->pmat,red->psubcomm->n,subcomm,MAT_INITIAL_MATRIX,&red->pmats);CHKERRQ(ierr);
ierr = KSPSetOperators(red->ksp,red->pmats,red->pmats);CHKERRQ(ierr);
/* get working vectors xsub and ysub */
ierr = MatCreateVecs(red->pmats,&red->xsub,&red->ysub);CHKERRQ(ierr);
/* create working vectors xdup and ydup.
xdup concatenates all xsub's contigously to form a mpi vector over dupcomm (see PetscSubcommCreate_interlaced())
ydup concatenates all ysub and has empty local arrays because ysub's arrays will be place into it.
Note: we use communicator dupcomm, not PetscObjectComm((PetscObject)pc)! */
ierr = MatGetLocalSize(red->pmats,&mloc_sub,NULL);CHKERRQ(ierr);
ierr = VecCreateMPI(PetscSubcommContiguousParent(red->psubcomm),mloc_sub,PETSC_DECIDE,&red->xdup);CHKERRQ(ierr);
ierr = VecCreateMPIWithArray(PetscSubcommContiguousParent(red->psubcomm),1,mloc_sub,PETSC_DECIDE,NULL,&red->ydup);CHKERRQ(ierr);
/* create vecscatters */
if (!red->scatterin) { /* efficiency of scatterin is independent from psubcomm_type! */
IS is1,is2;
PetscInt *idx1,*idx2,i,j,k;
ierr = MatCreateVecs(pc->pmat,&x,0);CHKERRQ(ierr);
ierr = VecGetSize(x,&M);CHKERRQ(ierr);
ierr = VecGetOwnershipRange(x,&mstart,&mend);CHKERRQ(ierr);
mlocal = mend - mstart;
ierr = PetscMalloc2(red->psubcomm->n*mlocal,&idx1,red->psubcomm->n*mlocal,&idx2);CHKERRQ(ierr);
j = 0;
for (k=0; k<red->psubcomm->n; k++) {
for (i=mstart; i<mend; i++) {
idx1[j] = i;
idx2[j++] = i + M*k;
}
}
ierr = ISCreateGeneral(comm,red->psubcomm->n*mlocal,idx1,PETSC_COPY_VALUES,&is1);CHKERRQ(ierr);
ierr = ISCreateGeneral(comm,red->psubcomm->n*mlocal,idx2,PETSC_COPY_VALUES,&is2);CHKERRQ(ierr);
ierr = VecScatterCreate(x,is1,red->xdup,is2,&red->scatterin);CHKERRQ(ierr);
ierr = ISDestroy(&is1);CHKERRQ(ierr);
ierr = ISDestroy(&is2);CHKERRQ(ierr);
/* Impl below is good for PETSC_SUBCOMM_INTERLACED (no inter-process communication) and PETSC_SUBCOMM_CONTIGUOUS (communication within subcomm) */
ierr = ISCreateStride(comm,mlocal,mstart+ red->psubcomm->color*M,1,&is1);CHKERRQ(ierr);
ierr = ISCreateStride(comm,mlocal,mstart,1,&is2);CHKERRQ(ierr);
ierr = VecScatterCreate(red->xdup,is1,x,is2,&red->scatterout);CHKERRQ(ierr);
ierr = ISDestroy(&is1);CHKERRQ(ierr);
ierr = ISDestroy(&is2);CHKERRQ(ierr);
ierr = PetscFree2(idx1,idx2);CHKERRQ(ierr);
ierr = VecDestroy(&x);CHKERRQ(ierr);
}
} else { /* !red->useparallelmat */
ierr = KSPSetOperators(red->ksp,pc->mat,pc->pmat);CHKERRQ(ierr);
}
} else { /* pc->setupcalled */
if (red->useparallelmat) {
MatReuse reuse;
/* grab the parallel matrix and put it into processors of a subcomminicator */
/*--------------------------------------------------------------------------*/
if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
/* destroy old matrices */
ierr = MatDestroy(&red->pmats);CHKERRQ(ierr);
reuse = MAT_INITIAL_MATRIX;
} else {
reuse = MAT_REUSE_MATRIX;
}
ierr = MatCreateRedundantMatrix(pc->pmat,red->psubcomm->n,PetscSubcommChild(red->psubcomm),reuse,&red->pmats);CHKERRQ(ierr);
ierr = KSPSetOperators(red->ksp,red->pmats,red->pmats);CHKERRQ(ierr);
} else { /* !red->useparallelmat */
ierr = KSPSetOperators(red->ksp,pc->mat,pc->pmat);CHKERRQ(ierr);
}
}
if (pc->setfromoptionscalled) {
ierr = KSPSetFromOptions(red->ksp);CHKERRQ(ierr);
}
ierr = KSPSetUp(red->ksp);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
int main(int argc,char **args)
{
Mat C,Credundant;
MatInfo info;
PetscMPIInt rank,size,subsize;
PetscInt i,j,m = 3,n = 2,low,high,iglobal;
PetscInt Ii,J,ldim,nsubcomms;
PetscErrorCode ierr;
PetscBool flg_info,flg_mat;
PetscScalar v,one = 1.0;
Vec x,y;
MPI_Comm subcomm;
ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
ierr = PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);CHKERRQ(ierr);
ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRQ(ierr);
ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRQ(ierr);
n = 2*size;
ierr = MatCreate(PETSC_COMM_WORLD,&C);CHKERRQ(ierr);
ierr = MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n);CHKERRQ(ierr);
ierr = MatSetFromOptions(C);CHKERRQ(ierr);
ierr = MatSetUp(C);CHKERRQ(ierr);
/* Create the matrix for the five point stencil, YET AGAIN */
for (i=0; i<m; i++) {
for (j=2*rank; j<2*rank+2; j++) {
v = -1.0; Ii = j + n*i;
if (i>0) {J = Ii - n; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
if (i<m-1) {J = Ii + n; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
if (j>0) {J = Ii - 1; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
if (j<n-1) {J = Ii + 1; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
v = 4.0; ierr = MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES);CHKERRQ(ierr);
}
}
/* Add extra elements (to illustrate variants of MatGetInfo) */
Ii = n; J = n-2; v = 100.0;
ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);
Ii = n-2; J = n; v = 100.0;
ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);
ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
/* Form vectors */
ierr = MatCreateVecs(C,&x,&y);CHKERRQ(ierr);
ierr = VecGetLocalSize(x,&ldim);CHKERRQ(ierr);
ierr = VecGetOwnershipRange(x,&low,&high);CHKERRQ(ierr);
for (i=0; i<ldim; i++) {
iglobal = i + low;
v = one*((PetscReal)i) + 100.0*rank;
ierr = VecSetValues(x,1,&iglobal,&v,INSERT_VALUES);CHKERRQ(ierr);
}
ierr = VecAssemblyBegin(x);CHKERRQ(ierr);
ierr = VecAssemblyEnd(x);CHKERRQ(ierr);
ierr = MatMult(C,x,y);CHKERRQ(ierr);
ierr = PetscOptionsHasName(NULL,NULL,"-view_info",&flg_info);CHKERRQ(ierr);
if (flg_info) {
ierr = PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO);CHKERRQ(ierr);
ierr = MatView(C,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = MatGetInfo(C,MAT_GLOBAL_SUM,&info);CHKERRQ(ierr);
ierr = PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"matrix information (global sums):\nnonzeros = %D, allocated nonzeros = %D\n",(PetscInt)info.nz_used,(PetscInt)info.nz_allocated);CHKERRQ(ierr);
ierr = MatGetInfo (C,MAT_GLOBAL_MAX,&info);CHKERRQ(ierr);
ierr = PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"matrix information (global max):\nnonzeros = %D, allocated nonzeros = %D\n",(PetscInt)info.nz_used,(PetscInt)info.nz_allocated);CHKERRQ(ierr);
}
ierr = PetscOptionsHasName(NULL,NULL,"-view_mat",&flg_mat);CHKERRQ(ierr);
if (flg_mat) {
ierr = MatView(C,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
}
/* Test MatCreateRedundantMatrix() */
nsubcomms = size;
ierr = PetscOptionsGetInt(NULL,NULL,"-nsubcomms",&nsubcomms,NULL);CHKERRQ(ierr);
ierr = MatCreateRedundantMatrix(C,nsubcomms,MPI_COMM_NULL,MAT_INITIAL_MATRIX,&Credundant);CHKERRQ(ierr);
ierr = MatCreateRedundantMatrix(C,nsubcomms,MPI_COMM_NULL,MAT_REUSE_MATRIX,&Credundant);CHKERRQ(ierr);
ierr = PetscObjectGetComm((PetscObject)Credundant,&subcomm);CHKERRQ(ierr);
ierr = MPI_Comm_size(subcomm,&subsize);CHKERRQ(ierr);
if (subsize==2 && flg_mat) {
ierr = PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_(subcomm),"\n[%d] Credundant:\n",rank);CHKERRQ(ierr);
ierr = MatView(Credundant,PETSC_VIEWER_STDOUT_(subcomm));CHKERRQ(ierr);
}
ierr = MatDestroy(&Credundant);CHKERRQ(ierr);
/* Test MatCreateRedundantMatrix() with user-provided subcomm */
{
PetscSubcomm psubcomm;
ierr = PetscSubcommCreate(PETSC_COMM_WORLD,&psubcomm);CHKERRQ(ierr);
ierr = PetscSubcommSetNumber(psubcomm,nsubcomms);CHKERRQ(ierr);
ierr = PetscSubcommSetType(psubcomm,PETSC_SUBCOMM_CONTIGUOUS);CHKERRQ(ierr);
/* enable runtime switch of psubcomm type, e.g., '-psubcomm_type interlaced */
ierr = PetscSubcommSetFromOptions(psubcomm);CHKERRQ(ierr);
ierr = MatCreateRedundantMatrix(C,nsubcomms,PetscSubcommChild(psubcomm),MAT_INITIAL_MATRIX,&Credundant);CHKERRQ(ierr);
ierr = MatCreateRedundantMatrix(C,nsubcomms,PetscSubcommChild(psubcomm),MAT_REUSE_MATRIX,&Credundant);CHKERRQ(ierr);
ierr = PetscSubcommDestroy(&psubcomm);CHKERRQ(ierr);
ierr = MatDestroy(&Credundant);CHKERRQ(ierr);
}
ierr = VecDestroy(&x);CHKERRQ(ierr);
ierr = VecDestroy(&y);CHKERRQ(ierr);
ierr = MatDestroy(&C);CHKERRQ(ierr);
ierr = PetscFinalize();
return ierr;
}
int main(int argc,char **args)
{
KSP subksp;
Mat A,subA;
Vec x,b,u,subb,subx,subu;
PetscViewer fd;
char file[PETSC_MAX_PATH_LEN];
PetscBool flg;
PetscErrorCode ierr;
PetscInt i,m,n,its;
PetscReal norm;
PetscMPIInt rank,size;
MPI_Comm comm,subcomm;
PetscSubcomm psubcomm;
PetscInt nsubcomm=1,id;
PetscScalar *barray,*xarray,*uarray,*array,one=1.0;
PetscInt type=1;
PetscInitialize(&argc,&args,(char*)0,help);
/* Load the matrix */
ierr = PetscOptionsGetString(NULL,"-f",file,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
if (!flg) SETERRQ(PETSC_COMM_WORLD,1,"Must indicate binary file with the -f option");
ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,file,FILE_MODE_READ,&fd);CHKERRQ(ierr);
/* Load the matrix; then destroy the viewer.*/
ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr);
ierr = MatLoad(A,fd);CHKERRQ(ierr);
ierr = PetscViewerDestroy(&fd);CHKERRQ(ierr);
ierr = PetscObjectGetComm((PetscObject)A,&comm);CHKERRQ(ierr);
ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
/* Create rhs vector b */
ierr = MatGetLocalSize(A,&m,NULL);CHKERRQ(ierr);
ierr = VecCreate(PETSC_COMM_WORLD,&b);CHKERRQ(ierr);
ierr = VecSetSizes(b,m,PETSC_DECIDE);CHKERRQ(ierr);
ierr = VecSetFromOptions(b);CHKERRQ(ierr);
ierr = VecSet(b,one);CHKERRQ(ierr);
ierr = VecDuplicate(b,&x);CHKERRQ(ierr);
ierr = VecDuplicate(b,&u);CHKERRQ(ierr);
ierr = VecSet(x,0.0);CHKERRQ(ierr);
/* Test MatGetMultiProcBlock() */
ierr = PetscOptionsGetInt(NULL,"-nsubcomm",&nsubcomm,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetInt(NULL,"-subcomm_type",&type,NULL);CHKERRQ(ierr);
ierr = PetscSubcommCreate(comm,&psubcomm);CHKERRQ(ierr);
ierr = PetscSubcommSetNumber(psubcomm,nsubcomm);CHKERRQ(ierr);
if (type == PETSC_SUBCOMM_GENERAL) { /* user provides color, subrank and duprank */
PetscMPIInt color,subrank,duprank,subsize;
duprank = size-1 - rank;
subsize = size/nsubcomm;
if (subsize*nsubcomm != size) SETERRQ2(comm,PETSC_ERR_SUP,"This example requires nsubcomm %D divides nproc %D",nsubcomm,size);
color = duprank/subsize;
subrank = duprank - color*subsize;
ierr = PetscSubcommSetTypeGeneral(psubcomm,color,subrank,duprank);CHKERRQ(ierr);
} else if (type == PETSC_SUBCOMM_CONTIGUOUS) {
ierr = PetscSubcommSetType(psubcomm,PETSC_SUBCOMM_CONTIGUOUS);CHKERRQ(ierr);
} else if (type == PETSC_SUBCOMM_INTERLACED) {
ierr = PetscSubcommSetType(psubcomm,PETSC_SUBCOMM_INTERLACED);CHKERRQ(ierr);
} else SETERRQ1(psubcomm->parent,PETSC_ERR_SUP,"PetscSubcommType %D is not supported yet",type);
subcomm = psubcomm->comm;
ierr = PetscOptionsHasName(NULL, "-subcomm_view", &flg);CHKERRQ(ierr);
if (flg) {
PetscMPIInt subsize,subrank,duprank;
ierr = MPI_Comm_size((MPI_Comm)subcomm,&subsize);CHKERRQ(ierr);
ierr = MPI_Comm_rank((MPI_Comm)subcomm,&subrank);CHKERRQ(ierr);
ierr = MPI_Comm_rank((MPI_Comm)psubcomm->dupparent,&duprank);CHKERRQ(ierr);
ierr = PetscSynchronizedPrintf(comm,"[%D], color %D, sub-size %D, sub-rank %D, duprank %D\n",rank,psubcomm->color,subsize,subrank,duprank);
ierr = PetscSynchronizedFlush(comm);CHKERRQ(ierr);
}
/* Create subA */
ierr = MatGetMultiProcBlock(A,subcomm,MAT_INITIAL_MATRIX,&subA);CHKERRQ(ierr);
/* Create sub vectors without arrays. Place b's and x's local arrays into subb and subx */
ierr = MatGetLocalSize(subA,&m,&n);CHKERRQ(ierr);
ierr = VecCreateMPIWithArray(subcomm,1,m,PETSC_DECIDE,NULL,&subb);CHKERRQ(ierr);
ierr = VecCreateMPIWithArray(subcomm,1,n,PETSC_DECIDE,NULL,&subx);CHKERRQ(ierr);
ierr = VecCreateMPIWithArray(subcomm,1,n,PETSC_DECIDE,NULL,&subu);CHKERRQ(ierr);
ierr = VecGetArray(b,&barray);CHKERRQ(ierr);
ierr = VecGetArray(x,&xarray);CHKERRQ(ierr);
ierr = VecGetArray(u,&uarray);CHKERRQ(ierr);
ierr = VecPlaceArray(subb,barray);CHKERRQ(ierr);
ierr = VecPlaceArray(subx,xarray);CHKERRQ(ierr);
ierr = VecPlaceArray(subu,uarray);CHKERRQ(ierr);
/* Create linear solvers associated with subA */
ierr = KSPCreate(subcomm,&subksp);CHKERRQ(ierr);
ierr = KSPSetOperators(subksp,subA,subA,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
ierr = KSPSetFromOptions(subksp);CHKERRQ(ierr);
/* Solve sub systems */
ierr = KSPSolve(subksp,subb,subx);CHKERRQ(ierr);
ierr = KSPGetIterationNumber(subksp,&its);CHKERRQ(ierr);
/* check residual */
ierr = MatMult(subA,subx,subu);CHKERRQ(ierr);
ierr = VecAXPY(subu,-1.0,subb);CHKERRQ(ierr);
ierr = VecNorm(u,NORM_2,&norm);CHKERRQ(ierr);
if (norm > 1.e-4 && !rank) {
ierr = PetscPrintf(PETSC_COMM_WORLD,"[%D] Number of iterations = %3D\n",rank,its);CHKERRQ(ierr);
printf("Error: Residual norm of each block |subb - subA*subx |= %G\n",norm);
}
ierr = VecResetArray(subb);CHKERRQ(ierr);
ierr = VecResetArray(subx);CHKERRQ(ierr);
ierr = VecResetArray(subu);CHKERRQ(ierr);
ierr = PetscOptionsGetInt(NULL,"-subvec_view",&id,&flg);CHKERRQ(ierr);
if (flg && rank == id) {
ierr = PetscPrintf(PETSC_COMM_SELF,"[%D] subb:\n", rank);
ierr = VecGetArray(subb,&array);CHKERRQ(ierr);
for (i=0; i<m; i++) printf("%G\n",PetscRealPart(array[i]));
ierr = VecRestoreArray(subb,&array);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_SELF,"[%D] subx:\n", rank);
ierr = VecGetArray(subx,&array);CHKERRQ(ierr);
for (i=0; i<m; i++) printf("%G\n",PetscRealPart(array[i]));
ierr = VecRestoreArray(subx,&array);CHKERRQ(ierr);
}
ierr = VecRestoreArray(x,&xarray);CHKERRQ(ierr);
ierr = VecRestoreArray(b,&barray);CHKERRQ(ierr);
ierr = VecRestoreArray(u,&uarray);CHKERRQ(ierr);
ierr = MatDestroy(&subA);CHKERRQ(ierr);
ierr = VecDestroy(&subb);CHKERRQ(ierr);
ierr = VecDestroy(&subx);CHKERRQ(ierr);
ierr = VecDestroy(&subu);CHKERRQ(ierr);
ierr = KSPDestroy(&subksp);CHKERRQ(ierr);
ierr = PetscSubcommDestroy(&psubcomm);CHKERRQ(ierr);
ierr = MatDestroy(&A);CHKERRQ(ierr); ierr = VecDestroy(&b);CHKERRQ(ierr);
ierr = VecDestroy(&u);CHKERRQ(ierr); ierr = VecDestroy(&x);CHKERRQ(ierr);
ierr = PetscFinalize();
return 0;
}
