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; 55 j = 0; 56 v = 100; 57 PetscCall(MatSetValues(C, 1, &i, 1, &j, &v, INSERT_VALUES)); 58 } 59 PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY)); 60 PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY)); 61 62 PetscCall(MatCreateSubMatrix(C, isrow, NULL, MAT_REUSE_MATRIX, &A)); 63 PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_COMMON)); 64 PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD)); 65 PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD)); 66 67 PetscCall(ISDestroy(&isrow)); 68 PetscCall(ISDestroy(&iscol)); 69 PetscCall(MatDestroy(&A)); 70 PetscCall(MatDestroy(&C)); 71 PetscCall(PetscFinalize()); 72 return 0; 73 } 74 75 /*TEST 76 77 test: 78 nsize: 2 79 80 TEST*/ 81