www.pudn.com > NumericalComputing.rar > randncond.m, change:2002-03-29,size:596b


% RANDNCOND  Condition of random matrices 
 
nmax = 100; 
n = 2:nmax; 
kappalo = n.^(1/2); 
kappahi = 500*n.^3; 
 
shg 
clf reset 
h = loglog(n,[kappalo; kappahi],'-',nmax,NaN,'.'); 
set(h(1:2),'color',[0 2/3 0]); 
set(gca,'xtick',[2:2:10 20:20:nmax]) 
kappamax = 1.e6; 
axis([2 nmax 2 kappamax]) 
stop = uicontrol('pos',[20 10 40 25], ... 
   'style','toggle','string','stop','value',0); 
 
h = h(3); 
set(h,'erasemode','none','color','blue') 
while get(stop,'value') ~= 1 
   n = ceil(rand*nmax); 
   A = randn(n,n); 
   kappa = condest(A); 
   set(h,'xdata',n,'ydata',kappa) 
   drawnow 
end