 
figure
y=[123	302	629	1254	2429	4479     6600 8600]
%  x=[625	2500	10000	40000	160000	640000	1440000  2560000 ]
 x=[25	50	100	200	400	800		1200	1600 ]
 loglog(x,y,'k-o')
 y./x
   ylabel('# time-steps')
   xlabel('L')
   ylim([10^2 2*10^4])
   xlim([10^1 2*10^3])
  