# probable

Easy and reasonably efficient probabilistic programming and random generation http://github.com/alpmestan/probable

 Latest on Hackage: 0.1.3

This package is not currently in any snapshots. If you're interested in using it, we recommend adding it to Stackage Nightly. Doing so will make builds more reliable, and allow stackage.org to host generated Haddocks.

Maintained by

# probable

Simple random value generation for haskell, using an efficient random generator and minimizing system calls. But the library also lets you work with distributions over a finite set, adapting code from Eric Kiddâ€™s posts, and all the usual distributions covered in the statistics package.

You can see how it looks in examples, or below. You can view the documentation for 0.1 here.

## Example

Simple example of random generation for your types, using probable.

``````module Main where

import Control.Applicative
import Math.Probable

import qualified Data.Vector.Unboxed as VU

data Person = Person
{ age    :: Int
, weight :: Double
, salary :: Int
} deriving (Eq, Show)

person :: RandT IO Person
person =
Person <\$> intIn (1, 100)
<*> doubleIn (2, 130)
<*> intIn (500, 10000)

randomPersons :: Int -> IO [Person]
randomPersons n = mwc \$ listOf n person

randomDoubles :: Int -> IO (VU.Vector Double)
randomDoubles n = mwc \$ vectorOf n double

main :: IO ()
main = do
randomPersons 10 >>= mapM_ print
randomDoubles 10 >>= VU.mapM_ print
``````

Distributions over finite sets, conditional probabilities and random sampling.

``````module Main where

import Math.Probable

import qualified Data.Vector as V

data Book = Interesting
| Boring
deriving (Eq, Show)

bookPrior :: Finite d => d Book
bookPrior = weighted [ (Interesting, 0.2)
, (Boring, 0.8)
]

twoBooks :: Finite d => d (Book, Book)
twoBooks = do
book1 <- bookPrior
book2 <- bookPrior
return (book1, book2)

sampleBooks :: RandT IO (V.Vector Book)
sampleBooks = vectorOf 10 bookPrior

oneInteresting :: Fin (Book, Book)
oneInteresting = bayes \$ do
(b1, b2) <- twoBooks
condition (b1 == Interesting || b2 == Interesting)
return (b1, b2)

main :: IO ()
main = do
print \$ exact bookPrior
mwc sampleBooks >>= print
print \$ exact twoBooks
print \$ exact oneInteresting
``````

# Contact

This library is written and maintained by Alp Mestanogullari.

Feel free to contact me for any feedback, comment, suggestion, bug report and what not.

Depends on 7 packages:
Used by 2 packages: