On Wed, 2010-06-02 at 16:11 +0200, Henning Thielemann wrote:
Sorry, I missed this post.
Maciej Piechotka schrieb:
Well - i tried to write some package dealing with distributions etc.
If you have something like that:
instance ... => Distribution (Linear a) a where rand (Linear f s) g = let (gf, gt) = genRange g (v, g') = next g in (g', f + (fromIntegral v * s) / fromIntegral (gt - gf))
(I haven't check it but IMHO it is right implementation)
Now I have following options:
- Implement per Int/Int8/... - Implement IntegerLinear and FractionalLinear separatly
That is, what you need is a general division with rounding. But you might more generally want a custom type class with a method that selects an element from a set for given parameters gf, gt, v. This way, you could also handle distributions on Enumeration types. You certainly you do not want, say a division operation on Monday, Tuesday, ..., Sunday, but having a probability distribution of weekdays is very reasonable.
Btw. you may want to have a look at: http://hackage.haskell.org/package/probability
Hmm. Thanks - however I fail to figure out how to do something like: "generate a random number with normal distribution with average avg and standard deviation stdev". Regards