/* nag_dsgesv (f07acc) Example Program. * * Copyright 2009, Numerical Algorithms Group. * * Mark 23, 2011. */ #include #include #include #include #include int main(void) { /* Scalars */ Integer exit_status = 0; Integer i, iter, j, n, nrhs, pda, pdb, pdx; /* Arrays */ Integer *ipiv = 0; double *a = 0, *b = 0, *x = 0; /* Nag Types */ NagError fail; Nag_OrderType order; INIT_FAIL(fail); printf("nag_dsgesv (f07acc) Example Program Results\n\n"); /* Skip heading in data file*/ scanf("%*[^\n]"); scanf("%ld%ld%*[^\n]", &n, &nrhs); if (n < 0 || nrhs < 0) { printf("Invalid n or nrhs\n"); exit_status = 1; return exit_status; } pda = n; #ifdef NAG_COLUMN_MAJOR pdb = n; pdx = n; #define A(I, J) a[(J-1)*pda + I-1] #define B(I, J) b[(J-1)*pdb + I-1] order = Nag_ColMajor; #else pdb = nrhs; pdx = nrhs; #define A(I, J) a[(I-1)*pda + J-1] #define B(I, J) b[(I-1)*pdb + J-1] order = Nag_RowMajor; #endif /* Allocate memory */ if (!(a = NAG_ALLOC(n*n, double)) || !(b = NAG_ALLOC(n*nrhs, double)) || !(x = NAG_ALLOC(n*nrhs, double)) || !(ipiv = NAG_ALLOC(n, Integer))) { printf("Allocation failure\n"); exit_status = -1; goto END; } /* Read A and B from data file*/ for (i = 1; i <= n; i++) for (j = 1; j <= n; j++) scanf("%lf", &A(i, j)); scanf("%*[^\n] "); for (i = 1; i <= n; i++) for (j = 1; j <= nrhs; j++) scanf("%lf", &B(i, j)); scanf("%*[^\n] "); /* Solve the equations Ax = b for x using nag_dsgesv (f07acc) * Mixed precision real system solver. */ nag_dsgesv(order, n, nrhs, a, pda, ipiv, b, pdb, x, pdx, &iter, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dsgesv (f07acc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print solution using * nag_gen_real_mat_print (x04cac) */ fflush(stdout); nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, nrhs, x, pdx, "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; } /* Print pivot indices*/ printf("\nPivot indices\n"); for (i = 0; i < n; i++) printf("%11ld%s", ipiv[i], (i+1)%7?" ":"\n"); printf("\n"); END: if (a) NAG_FREE(a); if (b) NAG_FREE(b); if (x) NAG_FREE(x); if (ipiv) NAG_FREE(ipiv); return exit_status; } #undef A #undef B