1 2 static char help[] = "Tests MatCreateSubmatrix() with certain entire rows of matrix, modified from ex181.c."; 3 4 #include <petscmat.h> 5 6 int main(int argc,char **args) 7 { 8 Mat C,A; 9 PetscInt i,j,m = 3,n = 2,rstart,rend,cstart,cend; 10 PetscMPIInt size,rank; 11 PetscScalar v; 12 IS isrow,iscol; 13 14 PetscFunctionBeginUser; 15 PetscCall(PetscInitialize(&argc,&args,(char*)0,help)); 16 PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank)); 17 PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size)); 18 n = 2*size; 19 20 PetscCall(MatCreate(PETSC_COMM_WORLD,&C)); 21 PetscCall(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n)); 22 PetscCall(MatSetFromOptions(C)); 23 PetscCall(MatSetUp(C)); 24 25 /* 26 This is JUST to generate a nice test matrix, all processors fill up 27 the entire matrix. This is not something one would ever do in practice. 28 */ 29 PetscCall(MatGetOwnershipRange(C,&rstart,&rend)); 30 for (i=rstart; i<rend; i++) { 31 for (j=0; j<m*n; j++) { 32 v = i + j + 1; 33 PetscCall(MatSetValues(C,1,&i,1,&j,&v,INSERT_VALUES)); 34 } 35 } 36 PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY)); 37 PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY)); 38 PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_COMMON)); 39 PetscCall(MatView(C,PETSC_VIEWER_STDOUT_WORLD)); 40 PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD)); 41 42 /* 43 Generate a new matrix consisting every column of the original matrix 44 */ 45 PetscCall(MatGetOwnershipRange(C,&rstart,&rend)); 46 PetscCall(MatGetOwnershipRangeColumn(C,&cstart,&cend)); 47 48 PetscCall(ISCreateStride(PETSC_COMM_WORLD,rend-rstart > 0 ? rend-rstart-1 : 0,rstart,1,&isrow)); 49 PetscCall(ISCreateStride(PETSC_COMM_WORLD,cend-cstart,cstart,1,&iscol)); 50 PetscCall(MatCreateSubMatrix(C,isrow,NULL,MAT_INITIAL_MATRIX,&A)); 51 52 /* Change C to test the case MAT_REUSE_MATRIX */ 53 if (rank == 0) { 54 i = 0; j = 0; v = 100; 55 PetscCall(MatSetValues(C,1,&i,1,&j,&v,INSERT_VALUES)); 56 } 57 PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY)); 58 PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY)); 59 60 PetscCall(MatCreateSubMatrix(C,isrow,NULL,MAT_REUSE_MATRIX,&A)); 61 PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_COMMON)); 62 PetscCall(MatView(A,PETSC_VIEWER_STDOUT_WORLD)); 63 PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD)); 64 65 PetscCall(ISDestroy(&isrow)); 66 PetscCall(ISDestroy(&iscol)); 67 PetscCall(MatDestroy(&A)); 68 PetscCall(MatDestroy(&C)); 69 PetscCall(PetscFinalize()); 70 return 0; 71 } 72 73 /*TEST 74 75 test: 76 nsize: 2 77 78 TEST*/ 79