/* nag_zeros_real_poly (c02agc) Example Program. * * Copyright 1991 Numerical Algorithms Group. * * Mark 2, 1991. * * Mark 8 revised, 2004. */ #include #include #include #include #include int main(void) { Nag_Boolean scale; Complex *z=0; Integer exit_status=0, i, n, nroot; NagError fail; double *a=0; INIT_FAIL(fail); Vprintf("nag_zeros_real_poly (c02agc) Example Program Results\n"); /* Skip heading in data file */ Vscanf("%*[^\n]"); Vscanf("%ld", &n); if (n>0) { scale = Nag_TRUE; if ( !( a = NAG_ALLOC(n+1, double)) || !( z = NAG_ALLOC(n, Complex)) ) { Vprintf("Allocation failure\n"); exit_status = -1; goto END; } } else { Vprintf("Invalid n.\n"); exit_status = 1; return exit_status; } for (i=0; i<=n; i++) Vscanf("%lf", &a[i]); Vprintf("\nDegree of polynomial = %4ld\n\n", n); /* nag_zeros_real_poly (c02agc). * Zeros of a polynomial with real coefficients */ nag_zeros_real_poly(n, a, scale, z, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_zeros_real_poly (c02agc).\n%s\n", fail.message); exit_status = 1; goto END; } Vprintf("Roots of polynomial\n\n"); nroot = 1; while(nroot<=n) { if (z[nroot-1].im==0.0) { Vprintf("z = %12.4e\n", z[nroot-1].re); nroot += 1; } else { Vprintf("z = %12.4e +/- %14.4e\n", z[nroot-1].re, fabs(z[nroot-1].im)); nroot += 2; } } END: if (a) NAG_FREE(a); if (z) NAG_FREE(z); return exit_status; }