Limitcycle initialization

For limit cycles the same problems occur as with equilibria, a limit cycle continuation can't be done by just calling the continuer as
[x,v,s,h,f]=cont(@limitcycle, x0, v0, opt)
The limit cycle curve file has to know Also an initial cycle x0 has to be known. All this information can be supplied using any of the following three starting functions. All three return an initial cycle x0 as well as its tangent vector v0.