1 static char help[] = "Tests MatCreateSubmatrix() with certain entire rows of matrix, modified from ex181.c."; 2 3 #include <petscmat.h> 4 5 int main(int argc, char **args) 6 { 7 Mat C, A; 8 PetscInt i, j, m = 3, n = 2, rstart, rend, cstart, cend; 9 PetscMPIInt size, rank; 10 PetscScalar v; 11 IS isrow, iscol; 12 13 PetscFunctionBeginUser; 14 PetscCall(PetscInitialize(&argc, &args, (char *)0, help)); 15 PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank)); 16 PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size)); 17 n = 2 * size; 18 19 PetscCall(MatCreate(PETSC_COMM_WORLD, &C)); 20 PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n)); 21 PetscCall(MatSetFromOptions(C)); 22 PetscCall(MatSetUp(C)); 23 24 /* 25 This is JUST to generate a nice test matrix, all processors fill up 26 the entire matrix. This is not something one would ever do in practice. 27 */ 28 PetscCall(MatGetOwnershipRange(C, &rstart, &rend)); 29 for (i = rstart; i < rend; i++) { 30 for (j = 0; j < m * n; j++) { 31 v = i + j + 1; 32 PetscCall(MatSetValues(C, 1, &i, 1, &j, &v, INSERT_VALUES)); 33 } 34 } 35 PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY)); 36 PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY)); 37 PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_COMMON)); 38 PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD)); 39 PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD)); 40 41 /* 42 Generate a new matrix consisting every column of the original matrix 43 */ 44 PetscCall(MatGetOwnershipRange(C, &rstart, &rend)); 45 PetscCall(MatGetOwnershipRangeColumn(C, &cstart, &cend)); 46 47 PetscCall(ISCreateStride(PETSC_COMM_WORLD, rend - rstart > 0 ? rend - rstart - 1 : 0, rstart, 1, &isrow)); 48 PetscCall(ISCreateStride(PETSC_COMM_WORLD, cend - cstart, cstart, 1, &iscol)); 49 PetscCall(MatCreateSubMatrix(C, isrow, NULL, MAT_INITIAL_MATRIX, &A)); 50 51 /* Change C to test the case MAT_REUSE_MATRIX */ 52 if (rank == 0) { 53 i = 0; 54 j = 0; 55 v = 100; 56 PetscCall(MatSetValues(C, 1, &i, 1, &j, &v, INSERT_VALUES)); 57 } 58 PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY)); 59 PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY)); 60 61 PetscCall(MatCreateSubMatrix(C, isrow, NULL, MAT_REUSE_MATRIX, &A)); 62 PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_COMMON)); 63 PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD)); 64 PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD)); 65 66 PetscCall(ISDestroy(&isrow)); 67 PetscCall(ISDestroy(&iscol)); 68 PetscCall(MatDestroy(&A)); 69 PetscCall(MatDestroy(&C)); 70 PetscCall(PetscFinalize()); 71 return 0; 72 } 73 74 /*TEST 75 76 test: 77 nsize: 2 78 79 TEST*/ 80