pixelfunc
sphtfunc
visufunc
fitsfunc
rotator
projector
zoomtool
Alm.
getlm
Get the l and m from index and lmax.
lmax : int
The maximum l defining the alm layout
i : int or None
The index for which to compute the l and m. If None, the function return l and m for i=0..Alm.getsize(lmax)