/* nag_dgeequ (f07afc) Example Program. * * Copyright 2008 Numerical Algorithms Group. * * Mark 23, 2011. */ #include #include #include #include #include #include int main(void) { /* Scalars */ double amax, big, colcnd, rowcnd, small; Integer i, j, m, n, pda; Integer exit_status = 0; /* Arrays */ double *a = 0, *c = 0, *r = 0; /* Nag Types */ NagError fail; Nag_OrderType order; Nag_Boolean scaled = Nag_FALSE; #ifdef NAG_COLUMN_MAJOR #define A(I, J) a[(J-1)*pda + I - 1] order = Nag_ColMajor; #else #define A(I, J) a[(I-1)*pda + J - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_dgeequ (f07afc) Example Program Results\n\n"); /* Skip heading in data file */ scanf("%*[^\n]"); scanf("%ld%*[^\n]", &n); if (n < 0) { printf("Invalid n\n"); exit_status = 1; return exit_status; } m = n; #ifdef NAG_COLUMN_MAJOR pda = m; #else pda = n; #endif /* Allocate memory */ if (!(a = NAG_ALLOC(m*n, double)) || !(c = NAG_ALLOC(n, double)) || !(r = NAG_ALLOC(m, double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } /* Read the N by N matrix A from data file */ for (i = 1; i <= n; ++i) for (j = 1; j <= n; ++j) scanf("%lf", &A(i, j)); scanf("%*[^\n]"); /* Print the matrix A using nag_gen_real_mat_print (x04cac) */ fflush(stdout); nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n, a, pda, "Matrix A", 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; } printf("\n"); /* Compute row and column scaling factors using nag_dgeequ (f07afc) */ nag_dgeequ(order, m, n, a, pda, r, c, &rowcnd, &colcnd, &amax, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dgeequ (f07afc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print rowcnd, colcnd, amax and the scale factors */ printf("rowcnd = %10.1e, colcnd = %10.1e, amax = %10.1e\n\n", rowcnd, colcnd, amax); printf("Row scale factors\n"); for (i = 1; i <= n; ++i) printf("%11.1e%s", r[i-1], i%7 == 0 || i == n?"\n":" "); printf("\n\nColumn scale factors\n"); for (i = 1; i <= n; ++i) printf("%11.1e%s", c[i-1], i%7 == 0 || i == n?"\n":" "); printf("\n"); /* Compute values close to underflow and overflow using * nag_real_safe_small_number (x02amc), nag_machine_precision (x02ajc) and * nag_real_base (x02bhc) */ small = nag_real_safe_small_number / nag_machine_precision * nag_real_base; big = 1.0 / small; if (colcnd < 0.1) { scaled = Nag_TRUE; /* column scale A */ for (j = 1; j <= n; ++j) for (i = 1; i <= n; ++i) A(i, j) = A(i, j) * c[j - 1]; } if (rowcnd < 0.1 || amax < small || amax > big) { /* row scale A */ scaled = Nag_TRUE; for (j = 1; j <= n; ++j) for (i = 1; i <= n; ++i) A(i, j) = r[i-1] * A(i, j); } if (scaled) { /* Print the row and column scaled matrix using * nag_gen_real_mat_print (x04cac) */ fflush(stdout); nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n, a, pda, "Scaled matrix", 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(a); NAG_FREE(c); NAG_FREE(r); return exit_status; }