% discretization

function yd=discr(fy,my,t,dis,fil,m)

if fil==1
  yl=-5;                               % lower bound of output y
  yu=5;                              % upper bound of output y
  yr=yu-yl;
  y1=yl+dis*yr/m;
  y2=yl+dis*yr/m+yr/m;
  if fy(t)<=y1
    yd=1;
  elseif fy(t)<=y2
    yd=2;
  else 
    yd=3;
  end
else
  yl=-3;
  yu=3;
  yr=yu-yl;
  y1=yl+dis*yr/m;
  y2=yl+dis*yr/m+yr/m;
  if fy(t)<=y1
    yd=1;
  elseif fy(t)<=2 
    yd=2;
  else
    yd=3;
  end
end