What do you consider to be the specification of logBase? Exact floating-point numbers don't exist, so it has to return an approximation. The standard doesn't give any guarantees as to the precision of the approximation. Is a precision of 0.00000000000004 not satisfactory for you?
2009/8/21 Roberto <plasterm...@hotmail.com>: > Hi, > > There is a mistake is logBase: > > $ ghci > GHCi, version 6.10.4: http://www.haskell.org/ghc/ :? for help > Loading package ghc-prim ... linking ... done. > Loading package integer ... linking ... done. > Loading package base ... linking ... done. > Prelude> logBase 10 10 > 1.0 > Prelude> logBase 10 100 > 2.0 > Prelude> logBase 10 1000 > 2.9999999999999996 <--- eeeerrgghhhh! > Prelude> logBase 10 10000 > 4.0 > > > My host is a Debian GNU/Linux 5.0.2 (lenny) with the following GHC packages: > > ii ghc6 6.10.4-1 > ii ghc6-doc 6.10.4-1 > ii libghc6-mtl-dev 1.1.0.2-7+b1 > ii libghc6-utf8-string-dev 0.3.5-1+b1 > ii libghc6-x11-dev 1.4.5-6 > rc libghc6-x11-doc 1.4.2-1 > ii libghc6-x11-xft-dev 0.3-3+b3 > ii libghc6-xmonad-contrib-dev 0.8.1-3+b3 > rc libghc6-xmonad-contrib-doc 0.8-2 > ii libghc6-xmonad-dev 0.8.1-5 > > Regards! > > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > -- Eugene Kirpichov Web IR developer, market.yandex.ru _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe