digamma function

[Ben Gamari]

My digamma package[1] implements an approximation to the digamma
function (due to Tom Minka). Considering that the math-functions package
already has a gamma implementation, it seems it would be natural to
merge digamma into this package. Alternatively (or additionally), James
Cook's gamma package also has a variety of gamma implementations and is
also a candidate for merging digamma into.

I don't mind maintaining digamma, but it might be easier for others if
there were a single package providing all of these functions. Do others
have an opinion on this? Are either (or both) of you interested in
picking up a digamma implementation?

Cheers,

 - Ben
 

[1] http://hackage.haskell.org/package/digamma