#include "defs.h"



/* make iterative improvement in net */

nroute()
{
	REG DPIN ip, Lp;
	REG i;
	INT odel, ndel, span, step, gain;

	if (npins < 3) return;
	for (span = npins ; span >= 2; span = (span + 1) >> 1)
	{
		gain = 0;
		for (step = 2; step <= span; step++)
		{
			i = 0;
loop:
			ip = &pinvec[i];
			Lp = &pinvec[i + step];
			odel = -1;
			while (Lp <= &pinvec[npins])
			{
				ndel = distance(ip, Lp);
				if (odel < 0)
					odel = distance(ip-1, Lp - 1);
				if ((ip->del + Lp->del) > (odel + ndel))
				{
					exchange(ip, Lp, odel, ndel);
					i = (step < i)? i - step : 0;
					gain++;
					goto loop;
				}
				odel = ndel;
				ip++; 
				Lp++; 
				i++;
			}
		}
		if (gain == 0) break;
	}
}