SpecialFuncs.EllipJacoby Method

Overload List

#SignatureDescription
1void EllipJacoby(Double u, Double m, Double Epsilon, ref Double sn, ref Double cn, ref Double dn)Jacobi elliptic functions sn, cn and dn.
2void EllipJacoby(Single u, Single m, Single Epsilon, ref Single sn, ref Single cn, ref Single dn)

Overload 1: void EllipJacoby(Double u, Double m, Double Epsilon, ref Double sn, ref Double cn, ref Double dn)

Jacobi elliptic functions sn, cn and dn.

#NameDescription
1uDefines value at which the functions will be evaluated (any real).
2mDefines the parameter m = k^2, a real value on the closed interval [0,1].
3EpsilonDefines the accuracy for the AGM/Landen iteration.
4snReturns Jacobi elliptic function sn(u,m).
5cnReturns Jacobi elliptic function cn(u,m).
6dnReturns Jacobi elliptic function dn(u,m).

Result: stored in self (calling object)

Remarks:

Computes the three Jacobi elliptic functions sn(u,m), cn(u,m) and dn(u,m) at argument u with parameter m = k^2 (modulus squared), using the descending Landen / AGM transformation to accuracy Epsilon. They are the inverse of the incomplete elliptic integral of the first kind: if u=\int_0^{\varphi} d\theta/\sqrt{1-m\sin^2\theta} then

sn(u,m)=sinvarphi, cn(u,m)=cosvarphi, dn(u,m)=sqrt(1-m sn^2(u,m)).

They satisfy the identities sn^2+cn^2=1 and dn^2+m\,sn^2=1. Degenerate limits handled exactly: at m=0, (sn,cn,dn)=(\sin u,\cos u,1); at m=1, (sn,cn,dn)=(\tanh u,\operatorname{sech} u,\operatorname{sech} u). Domain: u any real value; the parameter m on the closed interval [0,1]. For m<0 or m>1 an exception is raised.

See Also: SpecialFuncs.EllipComplete

Overload 2: void EllipJacoby(Single u, Single m, Single Epsilon, ref Single sn, ref Single cn, ref Single dn)

#NameTypeDescription
1uSinglescalar
2mSinglescalar
3EpsilonSinglescalar
4snSingle (ref)
5cnSingle (ref)
6dnSingle (ref)

Result: stored in self (calling object)