%make a tabulated angle_cosine potential
%V=k[1-cos(phi-phi0)]
%F=k*sin(phi0-phi)

howmany=1000
k=10
phi0=3*pi/4
phi=0:pi/howmany:pi';
V=k*(1-cos(phi-phi0));
F=k*sin(phi0-phi);
plot(phi,V,phi,F)
data(:,1)=phi;
data(:,2)=F;
data(:,3)=V;