/* nag_dtrexc (f08qfc) Example Program. * * Copyright 2001 Numerical Algorithms Group. * * Mark 7, 2001. */ #include #include #include #include #include int main(void) { /* Scalars */ Integer i, ifst, ilst, j, n, pdq, pdt; Integer exit_status = 0; NagError fail; Nag_OrderType order; /* Arrays */ double *q = 0, *t = 0; #ifdef NAG_COLUMN_MAJOR #define T(I, J) t[(J-1)*pdt + I - 1] order = Nag_ColMajor; #else #define T(I, J) t[(I-1)*pdt + J - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_dtrexc (f08qfc) Example Program Results\n\n"); /* Skip heading in data file */ scanf("%*[^\n] "); scanf("%ld%*[^\n] ", &n); #ifdef NAG_COLUMN_MAJOR pdq = 1; pdt = n; #else pdq = 1; pdt = n; #endif /* Allocate memory */ if (!(q = NAG_ALLOC(1 * 1, double)) || !(t = NAG_ALLOC(n * n, double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } /* Read T from data file */ for (i = 1; i <= n; ++i) { for (j = 1; j <= n; ++j) scanf("%lf", &T(i, j)); } scanf("%*[^\n] "); scanf("%ld%ld%*[^\n] ", &ifst, &ilst); /* Reorder the Schur factorization T */ /* nag_dtrexc (f08qfc). * Reorder Schur factorization of real matrix using * orthogonal similarity transformation */ nag_dtrexc(order, Nag_NotQ, n, t, pdt, q, pdq, &ifst, &ilst, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dtrexc (f08qfc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print reordered Schur form */ /* 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, n, t, pdt, "Reordered Schur form", 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: if (q) NAG_FREE(q); if (t) NAG_FREE(t); return exit_status; }