1 2 static char help[] = "Tests the use of MatSolveTranspose().\n\n"; 3 4 #include <petscmat.h> 5 6 int main(int argc, char **args) { 7 Mat C, A; 8 PetscInt i, j, m = 5, n = 5, Ii, J; 9 PetscScalar v, five = 5.0, one = 1.0; 10 IS isrow, row, col; 11 Vec x, u, b; 12 PetscReal norm; 13 MatFactorInfo info; 14 15 PetscFunctionBeginUser; 16 PetscCall(PetscInitialize(&argc, &args, (char *)0, help)); 17 PetscCall(PetscOptionsGetInt(NULL, NULL, "-m", &m, NULL)); 18 PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL)); 19 20 PetscCall(MatCreateSeqAIJ(PETSC_COMM_SELF, m * n, m * n, 5, NULL, &C)); 21 PetscCall(MatSetUp(C)); 22 23 /* create the matrix for the five point stencil, YET AGAIN*/ 24 for (i = 0; i < m; i++) { 25 for (j = 0; j < n; j++) { 26 v = -1.0; 27 Ii = j + n * i; 28 if (i > 0) { 29 J = Ii - n; 30 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 31 } 32 if (i < m - 1) { 33 J = Ii + n; 34 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 35 } 36 if (j > 0) { 37 J = Ii - 1; 38 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 39 } 40 if (j < n - 1) { 41 J = Ii + 1; 42 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 43 } 44 v = 4.0; 45 PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES)); 46 } 47 } 48 PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY)); 49 PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY)); 50 51 PetscCall(ISCreateStride(PETSC_COMM_SELF, (m * n) / 2, 0, 2, &isrow)); 52 PetscCall(MatZeroRowsIS(C, isrow, five, 0, 0)); 53 54 PetscCall(VecCreateSeq(PETSC_COMM_SELF, m * n, &u)); 55 PetscCall(VecDuplicate(u, &x)); 56 PetscCall(VecDuplicate(u, &b)); 57 PetscCall(VecSet(u, one)); 58 59 PetscCall(MatMultTranspose(C, u, b)); 60 61 /* Set default ordering to be Quotient Minimum Degree; also read 62 orderings from the options database */ 63 PetscCall(MatGetOrdering(C, MATORDERINGQMD, &row, &col)); 64 65 PetscCall(MatFactorInfoInitialize(&info)); 66 PetscCall(MatGetFactor(C, MATSOLVERPETSC, MAT_FACTOR_LU, &A)); 67 PetscCall(MatLUFactorSymbolic(A, C, row, col, &info)); 68 PetscCall(MatLUFactorNumeric(A, C, &info)); 69 PetscCall(MatSolveTranspose(A, b, x)); 70 71 PetscCall(ISView(row, PETSC_VIEWER_STDOUT_SELF)); 72 PetscCall(VecAXPY(x, -1.0, u)); 73 PetscCall(VecNorm(x, NORM_2, &norm)); 74 PetscCall(PetscPrintf(PETSC_COMM_SELF, "Norm of error %g\n", (double)norm)); 75 76 PetscCall(ISDestroy(&row)); 77 PetscCall(ISDestroy(&col)); 78 PetscCall(ISDestroy(&isrow)); 79 PetscCall(VecDestroy(&u)); 80 PetscCall(VecDestroy(&x)); 81 PetscCall(VecDestroy(&b)); 82 PetscCall(MatDestroy(&C)); 83 PetscCall(MatDestroy(&A)); 84 PetscCall(PetscFinalize()); 85 return 0; 86 } 87 88 /*TEST 89 90 test: 91 92 TEST*/ 93