## Random walk in one dimension

x2ave=[];
Nrw=1000;
Nstepsmax=10000;
inc=1000;
beg=1000;
dt=1;

for Nsteps=beg:inc:Nstepsmax;
  Nsteps
  x2=0;
  for m=1:Nrw
    r=rand_disc(Nsteps,0.45);
    x2+=sum(r)^2;
  endfor

  x2ave=[x2ave;x2/Nrw];

endfor

hold off
plot(dt*[beg:inc:Nstepsmax],x2ave,'b*;;')
[p,s]=polyfit(dt*[beg:inc:Nstepsmax]',x2ave,2);
pval=polyval(p,dt*[beg:inc:Nstepsmax]);
hold on
plot(dt*[beg:inc:Nstepsmax],pval,'r-');
hold off

D=p(2)/2
