2012/1/2 Sébastien Brisard <sebastien.bris...@m4x.org>: > Hi David, > 2012/1/2 David Erickson <halcyon1...@gmail.com>: >> Hi all- >> I'm new to using the Math package but it looks great. I need a couple >> distributions that aren't currently included, one as an example is the >> Generalized Extreme Value distribution >> (http://en.wikipedia.org/wiki/Generalized_extreme_value_distribution). >> I've created a new class GeneralizedExtremeValueDistributionImpl that >> extends AbstractContinuousDistribution and implements >> cumulativeProbability: >> >> @Override >> public double cumulativeProbability(double x) throws MathException { >> if (xi != 0) { >> return -FastMath.pow(FastMath.E, FastMath.pow(1d+xi*((x - >> mu)/sigma), -1/xi)); >> } else { >> return -FastMath.pow(FastMath.E, FastMath.pow(FastMath.E, >> -(x-mu)/sigma)); >> } >> } >> >> According to the API I also need to implement getInitialDomain, >> getDomainLowerBound, getDomainUpperBound, I looked at the existing >> docs and other implementations but I'm still unclear on how these are >> used, and what I should be returning, particularly since the existing >> implementations primarily check if p is < or > .5 and return a >> (frequently) static value. If anyone could help me shed some light on >> this I would be very appreciative. Primarily I just need to use the >> distribution to generate RandomVariable values. >> > the methods you are referring to are used to provide an initial > bracket to the solver for the computation of the inverse cumulative > probability. It can be a very crude initial guess, provided that it > indeed brackets the root (the solver will do the rest): hence the > static values you are referring to. > > Please note that these methods have recently been removed in the > latest version (3.0-SNAPSHOT). The implementation of new distributions > should now be much more straightforward. Are you adverse to using this > version? >
Thanks, I was able to get it to work. I could use 3.0 and in fact was looking to use it but didn't see a 3.0 snapshot in Maven, is there a Maven repo available receiving these snapshots? -David --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
