1 2 static char help[] = "Partition tiny grid.\n\n"; 3 4 /* 5 Include "petscmat.h" so that we can use matrices. Note that this file 6 automatically includes: 7 petscsys.h - base PETSc routines petscvec.h - vectors 8 petscmat.h - matrices 9 petscis.h - index sets 10 petscviewer.h - viewers 11 */ 12 #include <petscmat.h> 13 14 int main(int argc,char **args) 15 { 16 Mat A; 17 PetscMPIInt rank,size; 18 PetscInt *ia,*ja; 19 MatPartitioning part; 20 IS is,isn; 21 22 PetscCall(PetscInitialize(&argc,&args,(char*)0,help)); 23 PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size)); 24 PetscCheck(size == 4,PETSC_COMM_WORLD,PETSC_ERR_WRONG_MPI_SIZE,"Must run with 4 processors"); 25 PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank)); 26 27 PetscCall(PetscMalloc1(5,&ia)); 28 PetscCall(PetscMalloc1(16,&ja)); 29 if (rank == 0) { 30 ja[0] = 1; ja[1] = 4; ja[2] = 0; ja[3] = 2; ja[4] = 5; ja[5] = 1; ja[6] = 3; ja[7] = 6; 31 ja[8] = 2; ja[9] = 7; 32 ia[0] = 0; ia[1] = 2; ia[2] = 5; ia[3] = 8; ia[4] = 10; 33 } else if (rank == 1) { 34 ja[0] = 0; ja[1] = 5; ja[2] = 8; ja[3] = 1; ja[4] = 4; ja[5] = 6; ja[6] = 9; ja[7] = 2; 35 ja[8] = 5; ja[9] = 7; ja[10] = 10; ja[11] = 3; ja[12] = 6; ja[13] = 11; 36 ia[0] = 0; ia[1] = 3; ia[2] = 7; ia[3] = 11; ia[4] = 14; 37 } else if (rank == 2) { 38 ja[0] = 4; ja[1] = 9; ja[2] = 12; ja[3] = 5; ja[4] = 8; ja[5] = 10; ja[6] = 13; ja[7] = 6; 39 ja[8] = 9; ja[9] = 11; ja[10] = 14; ja[11] = 7; ja[12] = 10; ja[13] = 15; 40 ia[0] = 0; ia[1] = 3; ia[2] = 7; ia[3] = 11; ia[4] = 14; 41 } else { 42 ja[0] = 8; ja[1] = 13; ja[2] = 9; ja[3] = 12; ja[4] = 14; ja[5] = 10; ja[6] = 13; ja[7] = 15; 43 ja[8] = 11; ja[9] = 14; 44 ia[0] = 0; ia[1] = 2; ia[2] = 5; ia[3] = 8; ia[4] = 10; 45 } 46 47 PetscCall(MatCreateMPIAdj(PETSC_COMM_WORLD,4,16,ia,ja,NULL,&A)); 48 PetscCall(MatView(A,PETSC_VIEWER_STDOUT_WORLD)); 49 50 /* 51 Partition the graph of the matrix 52 */ 53 PetscCall(MatPartitioningCreate(PETSC_COMM_WORLD,&part)); 54 PetscCall(MatPartitioningSetAdjacency(part,A)); 55 PetscCall(MatPartitioningSetFromOptions(part)); 56 /* get new processor owner number of each vertex */ 57 PetscCall(MatPartitioningApply(part,&is)); 58 /* get new global number of each old global number */ 59 PetscCall(ISPartitioningToNumbering(is,&isn)); 60 PetscCall(ISView(isn,PETSC_VIEWER_STDOUT_WORLD)); 61 PetscCall(ISDestroy(&is)); 62 63 PetscCall(ISDestroy(&isn)); 64 PetscCall(MatPartitioningDestroy(&part)); 65 66 /* 67 Free work space. All PETSc objects should be destroyed when they 68 are no longer needed. 69 */ 70 PetscCall(MatDestroy(&A)); 71 72 PetscCall(PetscFinalize()); 73 return 0; 74 } 75