/* nag_sparse_sym_sol (f11jec) Example Program. * * Copyright 1998 Numerical Algorithms Group. * * Mark 5, 1998. * */ #include #include #include #include #include int main(void) { double *a = 0, *b = 0, *x = 0; double omega; double rnorm; double tol; Integer exit_status = 0; Integer *icol, *irow; Integer i, n, maxitn, itn, nnz; char nag_enum_arg[40]; Nag_SparseSym_Method method; Nag_SparseSym_PrecType precon; Nag_Sparse_Comm comm; NagError fail; INIT_FAIL(fail); printf("nag_sparse_sym_sol (f11jec) Example Program Results\n"); /* Skip heading in data file */ scanf(" %*[^\n]"); /* Read algorithmic parameters */ scanf("%ld%*[^\n]", &n); scanf("%ld%*[^\n]", &nnz); scanf("%s", nag_enum_arg); /* nag_enum_name_to_value(x04nac). * Converts NAG enum member name to value */ method = (Nag_SparseSym_Method) nag_enum_name_to_value(nag_enum_arg); scanf("%s%*[^\n]", nag_enum_arg); precon = (Nag_SparseSym_PrecType) nag_enum_name_to_value(nag_enum_arg); scanf("%lf%*[^\n]", &omega); scanf("%lf%ld%*[^\n]", &tol, &maxitn); /* Allocate memory */ x = NAG_ALLOC(n, double); b = NAG_ALLOC(n, double); a = NAG_ALLOC(nnz, double); irow = NAG_ALLOC(nnz, Integer); icol = NAG_ALLOC(nnz, Integer); if (!irow || !icol || !a || !x || !b) { printf("Allocation failure\n"); exit_status = 1; goto END; } /* Read the matrix a */ for (i = 1; i <= nnz; ++i) scanf("%lf%ld%ld%*[^\n]", &a[i-1], &irow[i-1], &icol[i-1]); /* Read right-hand side vector b and initial approximate solution x */ for (i = 1; i <= n; ++i) scanf("%lf", &b[i-1]); scanf(" %*[^\n]"); for (i = 1; i <= n; ++i) scanf("%lf", &x[i-1]); scanf(" %*[^\n]"); /* Solve Ax = b */ /* nag_sparse_sym_sol (f11jec). * Solver with Jacobi, SSOR, or no preconditioning * (symmetric) */ nag_sparse_sym_sol(method, precon, n, nnz, a, irow, icol, omega, b, tol, maxitn, x, &rnorm, &itn, &comm, &fail); printf(" %s%10ld%s\n", "Converged in", itn, " iterations"); printf(" %s%16.3e\n", "Final residual norm =", rnorm); /* Output x */ for (i = 1; i <= n; ++i) printf(" %16.4e\n", x[i-1]); END: if (irow) NAG_FREE(irow); if (icol) NAG_FREE(icol); if (a) NAG_FREE(a); if (x) NAG_FREE(x); if (b) NAG_FREE(b); return exit_status; }