Safe Haskell	None
Language	Haskell2010

Data.Random.Source.StdGen

Contents

Orphan instances

Description

This module provides functions useful for implementing new MonadRandom and RandomSource instances for state-abstractions containing StdGen values (the pure pseudorandom generator provided by the System.Random module in the "random" package), as well as instances for some common cases.

Synopsis

data StdGen
mkStdGen :: Int -> StdGen
newStdGen :: MonadIO m => m StdGen
getRandomPrimFromStdGenIO :: Prim a -> IO a
getRandomPrimFromRandomGenRef :: (Monad m, ModifyRef sr m g, RandomGen g) => sr -> Prim a -> m a
getRandomPrimFromRandomGenState :: forall g m a. (RandomGen g, MonadState g m) => Prim a -> m a

Documentation

data StdGen #

The standard pseudo-random number generator.

Instances

Eq StdGen
Instance details Defined in System.Random.Internal Methods (==) :: StdGen -> StdGen -> Bool # (/=) :: StdGen -> StdGen -> Bool #
Show StdGen
Instance details Defined in System.Random.Internal Methods showsPrec :: Int -> StdGen -> ShowS # show :: StdGen -> String # showList :: [StdGen] -> ShowS #
NFData StdGen
Instance details Defined in System.Random.Internal Methods rnf :: StdGen -> () #
RandomGen StdGen
Instance details Defined in System.Random.Internal Methods next :: StdGen -> (Int, StdGen) # genWord8 :: StdGen -> (Word8, StdGen) # genWord16 :: StdGen -> (Word16, StdGen) # genWord32 :: StdGen -> (Word32, StdGen) # genWord64 :: StdGen -> (Word64, StdGen) # genWord32R :: Word32 -> StdGen -> (Word32, StdGen) # genWord64R :: Word64 -> StdGen -> (Word64, StdGen) # genShortByteString :: Int -> StdGen -> (ShortByteString, StdGen) # genRange :: StdGen -> (Int, Int) # split :: StdGen -> (StdGen, StdGen) #
(Monad m, ModifyRef (STRef s StdGen) m StdGen) => RandomSource m (STRef s StdGen) Source #
Instance details Defined in Data.Random.Source.StdGen Methods getRandomPrimFrom :: STRef s StdGen -> Prim t -> m t Source # getRandomWord8From :: STRef s StdGen -> m Word8 Source # getRandomWord16From :: STRef s StdGen -> m Word16 Source # getRandomWord32From :: STRef s StdGen -> m Word32 Source # getRandomWord64From :: STRef s StdGen -> m Word64 Source # getRandomDoubleFrom :: STRef s StdGen -> m Double Source # getRandomNByteIntegerFrom :: STRef s StdGen -> Int -> m Integer Source #

mkStdGen :: Int -> StdGen #

Constructs a StdGen deterministically.

newStdGen :: MonadIO m => m StdGen #

Applies split to the current global pseudo-random generator, updates it with one of the results, and returns the other.

getRandomPrimFromStdGenIO :: Prim a -> IO a Source #

getRandomPrimFromRandomGenRef :: (Monad m, ModifyRef sr m g, RandomGen g) => sr -> Prim a -> m a Source #

Given a mutable reference to a RandomGen generator, we can make a RandomSource usable in any monad in which the reference can be modified.

getRandomPrimFromRandomGenState :: forall g m a. (RandomGen g, MonadState g m) => Prim a -> m a Source #

Similarly, getRandomWordFromRandomGenState x can be used in any "state" monad in the mtl sense whose state is a RandomGen generator. Additionally, the standard mtl state monads have MonadRandom instances which do precisely that, allowing an easy conversion of RVars and other Distribution instances to "pure" random variables.

Orphan instances

(Monad m, ModifyRef (STRef s StdGen) m StdGen) => RandomSource m (STRef s StdGen) Source #

Instance details

Methods

getRandomPrimFrom :: STRef s StdGen -> Prim t -> m t Source #

getRandomWord8From :: STRef s StdGen -> m Word8 Source #

getRandomWord16From :: STRef s StdGen -> m Word16 Source #

getRandomWord32From :: STRef s StdGen -> m Word32 Source #

getRandomWord64From :: STRef s StdGen -> m Word64 Source #

getRandomDoubleFrom :: STRef s StdGen -> m Double Source #

getRandomNByteIntegerFrom :: STRef s StdGen -> Int -> m Integer Source #