/* nag_zpbsvx (f07hpc) Example Program. * * Copyright 2004 Numerical Algorithms Group. * * Mark 23, 2011. */ #include #include #include #include #include int main(void) { /* Scalars */ double rcond; Integer exit_status = 0, i, j, kd, n, nrhs, pdab, pdafb, pdb, pdx; /* Arrays */ Complex *ab = 0, *afb = 0, *b = 0, *x = 0; double *berr = 0, *ferr = 0, *s = 0; char nag_enum_arg[40]; /* Nag Types */ NagError fail; Nag_UploType uplo; Nag_OrderType order; Nag_EquilibrationType equed; #ifdef NAG_COLUMN_MAJOR #define AB_UPPER(I, J) ab[(J-1)*pdab + kd + I - J] #define AB_LOWER(I, J) ab[(J-1)*pdab + I - J] #define B(I, J) b[(J-1)*pdb + I - 1] order = Nag_ColMajor; #else #define AB_UPPER(I, J) ab[(I-1)*pdab + J - I] #define AB_LOWER(I, J) ab[(I-1)*pdab + kd + J - I] #define B(I, J) b[(I-1)*pdb + J - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_zpbsvx (f07hpc) Example Program Results\n\n"); /* Skip heading in data file */ scanf("%*[^\n]"); scanf("%ld%ld%ld%*[^\n]", &n, &kd, &nrhs); if (n < 0 || kd < 0 || nrhs < 0) { printf("%s\n", "Invalid n or kd or nrhs"); exit_status = 1; goto END; } scanf(" %s%*[^\n]", nag_enum_arg); /* nag_enum_name_to_value(x04nac). * Converts NAG enum member name to value */ uplo = (Nag_UploType) nag_enum_name_to_value(nag_enum_arg); /* Allocate memory */ if (!(ab = NAG_ALLOC((kd+1) * n, Complex)) || !(afb = NAG_ALLOC((kd+1) * n, Complex)) || !(b = NAG_ALLOC(n * nrhs, Complex)) || !(x = NAG_ALLOC(n * nrhs, Complex)) || !(berr = NAG_ALLOC(nrhs, double)) || !(ferr = NAG_ALLOC(nrhs, double)) || !(s = NAG_ALLOC(n, double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } pdab = kd+1; pdafb = kd+1; #ifdef NAG_COLUMN_MAJOR pdb = n; pdx = n; #else pdb = nrhs; pdx = nrhs; #endif /* Read the upper or lower triangular part of the band matrix A */ /* from data file */ if (uplo == Nag_Upper) for (i = 1; i <= n; ++i) for (j = i; j <= MIN(n, i + kd); ++j) scanf(" ( %lf , %lf )", &AB_UPPER(i, j).re, &AB_UPPER(i, j).im); else for (i = 1; i <= n; ++i) for (j = MAX(1, i - kd); j <= i; ++j) scanf(" ( %lf , %lf )", &AB_LOWER(i, j).re, &AB_LOWER(i, j).im); scanf("%*[^\n]"); /* Read B from data file */ for (i = 1; i <= n; ++i) for (j = 1; j <= nrhs; ++j) scanf(" ( %lf , %lf )", &B(i, j).re, &B(i, j).im); scanf("%*[^\n]"); /* Solve the equations AX = B for X using nag_zpbsvx (f07hpc). */ nag_zpbsvx(order, Nag_EquilibrateAndFactor, uplo, n, kd, nrhs, ab, pdab, afb, pdafb, &equed, s, b, pdb, x, pdx, &rcond, ferr, berr, &fail); if (fail.code != NE_NOERROR && fail.code != NE_SINGULAR) { printf("Error from nag_zpbsvx (f07hpc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print solution using nag_gen_complx_mat_print_comp (x04dbc). */ fflush(stdout); nag_gen_complx_mat_print_comp(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, nrhs, x, pdx, Nag_BracketForm, "%7.4f", "Solution(s)", Nag_IntegerLabels, 0, Nag_IntegerLabels, 0, 80, 0, 0, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print error bounds, condition number and the form of equilibration */ printf("\nBackward errors (machine-dependent)\n"); for (j = 0; j < nrhs; ++j) printf("%11.1e%s", berr[j], j%7 == 6?"\n":" "); printf("\n\nEstimated forward error bounds (machine-dependent)\n"); for (j = 0; j < nrhs; ++j) printf("%11.1e%s", ferr[j], j%7 == 6?"\n":" "); printf("\n\nEstimate of reciprocal condition number\n%11.1e\n\n", rcond); if (equed == Nag_NoEquilibration) printf("A has not been equilibrated\n"); else if (equed == Nag_RowAndColumnEquilibration) printf("A has been row and column scaled as diag(S)*A*diag(S)\n"); if (fail.code == NE_SINGULAR) { printf("Error from nag_zpbsvx (f07hpc).\n%s\n", fail.message); exit_status = 1; } END: if (ab) NAG_FREE(ab); if (afb) NAG_FREE(afb); if (b) NAG_FREE(b); if (x) NAG_FREE(x); if (berr) NAG_FREE(berr); if (ferr) NAG_FREE(ferr); if (s) NAG_FREE(s); return exit_status; } #undef AB_UPPER #undef AB_LOWER #undef B