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 { 8 Mat C, A; 9 PetscInt i, j, m = 5, n = 5, Ii, J; 10 PetscScalar v, five = 5.0, one = 1.0; 11 IS isrow, row, col; 12 Vec x, u, b; 13 PetscReal norm; 14 MatFactorInfo info; 15 16 PetscFunctionBeginUser; 17 PetscCall(PetscInitialize(&argc, &args, (char *)0, help)); 18 PetscCall(PetscOptionsGetInt(NULL, NULL, "-m", &m, NULL)); 19 PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL)); 20 21 PetscCall(MatCreateSeqAIJ(PETSC_COMM_SELF, m * n, m * n, 5, NULL, &C)); 22 PetscCall(MatSetUp(C)); 23 24 /* create the matrix for the five point stencil, YET AGAIN*/ 25 for (i = 0; i < m; i++) { 26 for (j = 0; j < n; j++) { 27 v = -1.0; 28 Ii = j + n * i; 29 if (i > 0) { 30 J = Ii - n; 31 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 32 } 33 if (i < m - 1) { 34 J = Ii + n; 35 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 36 } 37 if (j > 0) { 38 J = Ii - 1; 39 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 40 } 41 if (j < n - 1) { 42 J = Ii + 1; 43 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 44 } 45 v = 4.0; 46 PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES)); 47 } 48 } 49 PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY)); 50 PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY)); 51 52 PetscCall(ISCreateStride(PETSC_COMM_SELF, (m * n) / 2, 0, 2, &isrow)); 53 PetscCall(MatZeroRowsIS(C, isrow, five, 0, 0)); 54 55 PetscCall(VecCreateSeq(PETSC_COMM_SELF, m * n, &u)); 56 PetscCall(VecDuplicate(u, &x)); 57 PetscCall(VecDuplicate(u, &b)); 58 PetscCall(VecSet(u, one)); 59 60 PetscCall(MatMultTranspose(C, u, b)); 61 62 /* Set default ordering to be Quotient Minimum Degree; also read 63 orderings from the options database */ 64 PetscCall(MatGetOrdering(C, MATORDERINGQMD, &row, &col)); 65 66 PetscCall(MatFactorInfoInitialize(&info)); 67 PetscCall(MatGetFactor(C, MATSOLVERPETSC, MAT_FACTOR_LU, &A)); 68 PetscCall(MatLUFactorSymbolic(A, C, row, col, &info)); 69 PetscCall(MatLUFactorNumeric(A, C, &info)); 70 PetscCall(MatSolveTranspose(A, b, x)); 71 72 PetscCall(ISView(row, PETSC_VIEWER_STDOUT_SELF)); 73 PetscCall(VecAXPY(x, -1.0, u)); 74 PetscCall(VecNorm(x, NORM_2, &norm)); 75 PetscCall(PetscPrintf(PETSC_COMM_SELF, "Norm of error %g\n", (double)norm)); 76 77 PetscCall(ISDestroy(&row)); 78 PetscCall(ISDestroy(&col)); 79 PetscCall(ISDestroy(&isrow)); 80 PetscCall(VecDestroy(&u)); 81 PetscCall(VecDestroy(&x)); 82 PetscCall(VecDestroy(&b)); 83 PetscCall(MatDestroy(&C)); 84 PetscCall(MatDestroy(&A)); 85 PetscCall(PetscFinalize()); 86 return 0; 87 } 88 89 /*TEST 90 91 test: 92 93 TEST*/ 94