Function: idealstar
Section: number_fields
C-Name: idealstar0
Prototype: GGD1,L,
Help: idealstar(nf,I,{flag=1}): gives the structure of (Z_K/I)^*. flag is
 optional, and can be 0: simply gives the structure as a 3-component vector v
 such that v[1] is the order (i.e. eulerphi(I)), v[2] is a vector of cyclic
 components, and v[3] is a vector giving the corresponding generators. If
 flag=1 (default), gives idealstarinit, i.e. a 6-component vector
 [I,v,fa,f2,U,V] where v is as above without the generators, fa is the prime
 ideal factorisation of I and f2, U and V are technical but essential to work
 in (Z_K/I)^*. Finally if flag=2, same as with flag=1 except that the
 generators are also given

