statistics 0.3.2 → 0.3.3

raw patch · 2 files changed

+33/−7 lines, 2 files

Files

• Statistics/RandomVariate.hs +32/−6
• statistics.cabal +1/−1

@@ -14,6 +14,7 @@     (     -- * Types       Gen+    , Seed     , Variate(..)     -- * Other distributions     , normal@@ -21,6 +22,9 @@     , create     , initialize     , withSystemRandom+    -- * State management+    , save+    , restore     -- * Helper functions     , uniformArray     -- * References@@ -74,6 +78,10 @@     --     -- * The range of random 'Integer' variates is the same as for     --   'Int'.+    --+    -- To generate a 'Float' variate with a range of [0,1), subtract+    -- 2**(-33).  To do the same with 'Double' variates, subtract+    -- 2**(-53).     uniform :: Gen s -> ST s a  -- Thanks to Duncan Coutts for finding the pattern below for@@ -171,20 +179,20 @@ {-# INLINE wordToBool #-}  wordToFloat :: Word32 -> Float-wordToFloat x = (fromIntegral i * m_inv_32) + 0.5 + m_inv_33+wordToFloat x      = (fromIntegral i * m_inv_32) + 0.5 + m_inv_33     where m_inv_33 = 1.16415321826934814453125e-10           m_inv_32 = 2.3283064365386962890625e-10-          i = fromIntegral x :: Int32+          i        = fromIntegral x :: Int32 {-# INLINE wordToFloat #-}  wordsToDouble :: Word32 -> Word32 -> Double-wordsToDouble x y = (fromIntegral a * m_inv_32 + (0.5 + m_inv_53) +-                    fromIntegral (b .&. 0xFFFFF) * m_inv_52) +wordsToDouble x y  = (fromIntegral a * m_inv_32 + (0.5 + m_inv_53) ++                     fromIntegral (b .&. 0xFFFFF) * m_inv_52)      where m_inv_52 = 2.220446049250313080847263336181640625e-16           m_inv_53 = 1.1102230246251565404236316680908203125e-16           m_inv_32 = 2.3283064365386962890625e-10-          a = fromIntegral x :: Int32-          b = fromIntegral y :: Int32+          a        = fromIntegral x :: Int32+          b        = fromIntegral y :: Int32 {-# INLINE wordsToDouble #-}  -- | State of the pseudo-random number generator.@@ -231,6 +239,24 @@         fini = lengthU seed {-# INLINE initialize #-}                                +-- | An immutable snapshot of the state of a 'Gen'.+newtype Seed = Seed (UArr Word32)+    deriving (Eq, Read, Show)++-- | Save the state of a 'Gen', for later use by 'restore'.+save :: Gen s -> ST s Seed+save (Gen q) = Seed `fmap` unsafeFreezeAllMU q+{-# INLINE save #-}++-- | Create a new 'Gen' that mirrors the state of a saved 'Seed'.+restore :: Seed -> ST s (Gen s)+restore (Seed s) = newMU n >>= fill+  where fill q = go 0 where+          go !i | i >= n    = return (Gen q)+                | otherwise = writeMU q i (indexU s i) >> go (i+1)+        n = lengthU s+{-# INLINE restore #-}+   -- | Using the current time as a seed, perform an action that uses a -- random variate generator.  This is a horrible fallback for Windows -- systems.

@@ -1,5 +1,5 @@ name:           statistics-version:        0.3.2+version:        0.3.3 synopsis:       A library of statistical types, data, and functions description:   This library provides a number of common functions and types useful