integer logarithms

 Math.NumberTheory.Logarithms and Math.NumberTheory.Powers.Integer
 from the arithmoi package.
 .
 Also provides GHC.Integer.Logarithms.Compat and
 Math.NumberTheory.Power.Natural modules, as well as some
 additional functions in migrated modules.
 .
 This package provides a library for the Haskell programming language.
 See http://www.haskell.org/ for more information on Haskell.