function rw=ricker(n,dt,nu)
total=dt*(n-1);
tover2=total/2.0;
t=-tover2:dt:tover2;
range=size(t,2);
for i=1:range
    y(i)=exp(-(pi^2)*(nu^2)*(t(i)^2));
    y2(i)= 1.0 - (2.0*(pi^2)*(nu^2)*(t(i)^2));
    rw(i)=y(i)*y2(i);
end