-------------------------------------------- -- Announcing: logfloat 0.8.5 -------------------------------------------- New official release of the logfloat package for manipulating log-domain floating numbers. This is primarily a maintenance release updating the documentation and with minor tweaks on typeclass-restricted polymorphism. Substantively, I also broke out a new type class for numbers which can represent transfinite values. This is primarily to deal with issues about Rationals and other Fractional types which cannot represent them. I also decided to switch the code over to *.hs format so that the Hackage build bot can generate the documentation more reliably. -------------------------------------------- -- Description -------------------------------------------- The main reason for casting numbers into the log-domain is to prevent underflow when multiplying many small probabilities as is done in Hidden Markov Models and other statistical models often used for natural language processing. The log-domain also helps prevent overflow when multiplying many large numbers. In rare cases it can speed up numerical computation (since addition is faster than multiplication, though logarithms are exceptionally slow), but the primary goal is to improve accuracy of results. A secondary goal has been to maximize efficiency since these computations are frequently done within a /O(n^3)/ loop. The Data.Numeric.LogFloat module provides a new data type LogFloat which handles all the conversions and optimizations and can be treated as any other number thanks to type classes. -------------------------------------------- -- Links -------------------------------------------- Homepage: http://code.haskell.org/~wren/ Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/logfloat Darcs: http://code.haskell.org/~wren/logfloat Haddock (Darcs version): http://code.haskell.org/~wren/logfloat/dist/doc/html/logfloat/ -- Live well, ~wren