/* nag_dtbtrs (f07vec) Example Program. * * Copyright 2001 Numerical Algorithms Group. * * Mark 7, 2001. */ #include #include #include #include #include int main(void) { /* Scalars */ Integer i, j, k, kd, n, nrhs, pdab, pdb; Integer exit_status = 0; Nag_UploType uplo; NagError fail; Nag_OrderType order; /* Arrays */ char nag_enum_arg[40]; double *ab = 0, *b = 0; #ifdef NAG_COLUMN_MAJOR #define AB_UPPER(I, J) ab[(J-1)*pdab + k + I - J - 1] #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 + k + J - I - 1] #define B(I, J) b[(I-1)*pdb + J - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_dtbtrs (f07vec) Example Program Results\n\n"); /* Skip heading in data file */ scanf("%*[^\n] "); scanf("%ld%ld%ld%*[^\n] ", &n, &kd, &nrhs); pdab = kd + 1; #ifdef NAG_COLUMN_MAJOR pdb = n; #else pdb = nrhs; #endif /* Allocate memory */ if (!(ab = NAG_ALLOC((kd+1) * n, double)) || !(b = NAG_ALLOC(n * nrhs, double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } /* Read A from data file */ scanf(" %39s%*[^\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); k = kd + 1; if (uplo == Nag_Upper) { for (i = 1; i <= n; ++i) { for (j = i; j <= MIN(i+kd, n); ++j) scanf("%lf", &AB_UPPER(i, j)); } scanf("%*[^\n] "); } else { for (i = 1; i <= n; ++i) { for (j = MAX(1, i-kd); j <= i; ++j) scanf("%lf", &AB_LOWER(i, j)); } scanf("%*[^\n] "); } /* Read B from data file */ for (i = 1; i <= n; ++i) { for (j = 1; j <= nrhs; ++j) scanf("%lf", &B(i, j)); scanf("%*[^\n] "); } /* Compute solution */ /* nag_dtbtrs (f07vec). * Solution of real band triangular system of linear * equations, multiple right-hand sides */ nag_dtbtrs(order, uplo, Nag_NoTrans, Nag_NonUnitDiag, n, kd, nrhs, ab, pdab, b, pdb, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dtbtrs (f07vec).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print solution */ /* nag_gen_real_mat_print (x04cac). * Print real general matrix (easy-to-use) */ fflush(stdout); nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, nrhs, b, pdb, "Solution(s)", 0, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_gen_real_mat_print (x04cac).\n%s\n", fail.message); exit_status = 1; goto END; } END: NAG_FREE(ab); NAG_FREE(b); return exit_status; }