ratio-int (empty) → 0.1

raw patch · 3 files changed

+105/−0 lines, 3 filesdep +basesetup-changed

Dependencies added: base

Files

• Data/RatioInt.hs +78/−0
• Setup.hs +2/−0
• ratio-int.cabal +25/−0

@@ -0,0 +1,78 @@+{-# LANGUAGE BangPatterns #-}+-- | Provides a specialised version of 'Data.Ratio' for 'Int'.+--+-- Runs about ten times faster than 'Data.Ratio' while being half as fast as+-- floating-point types.+module Data.RatioInt (RatioInt (numerator, denominator), (%)) where++import qualified Data.Ratio as R++-- | Rational numbers, with numerator and denominator of the 'Int' type.+data RatioInt = RatioInt {+      numerator   :: {-# UNPACK #-} !Int+    , denominator :: {-# UNPACK #-} !Int+    } deriving (Eq, Show, Read)++ratioZeroDenominatorError :: a+ratioZeroDenominatorError = error "Division by zero"++-- | Forms the ratio of two 'Int' numbers.+(%) :: Int -> Int -> RatioInt+x % y =  reduce (x * signum y) (abs y)+infixl 7  %++reduce :: Int -> Int -> RatioInt+reduce _   0 = ratioZeroDenominatorError+reduce !x !y = let d = gcd x y+               in RatioInt (x `quot` d) (y `quot` d)++-- Instances -------------------------------------------------------------------++instance Ord RatioInt where+    RatioInt x y <= RatioInt x' y' = x * y' <= x' * y+    RatioInt x y <  RatioInt x' y' = x * y' <  x' * y++instance Num RatioInt where+    RatioInt x y + RatioInt x' y' = reduce (x * y' + x' * y) (y * y')+    RatioInt x y - RatioInt x' y' = reduce (x * y' - x' * y) (y * y')+    RatioInt x y * RatioInt x' y' = reduce (x * x')          (y * y')++    negate (RatioInt x y)         = RatioInt (-x)            y+    abs    (RatioInt x y)         = RatioInt (abs x)         y+    signum (RatioInt x _)         = RatioInt (signum x)      1+    fromInteger x                 = RatioInt (fromInteger x) 1++instance Fractional RatioInt where+    (RatioInt x y) / (RatioInt x' y') = (x * y') % (y * x')++    recip (RatioInt 0 _) = ratioZeroDenominatorError+    recip (RatioInt x y)+        | x < 0          = RatioInt (negate y) (negate x)+        | otherwise      = RatioInt x          y++    fromRational r = fromInteger (R.numerator r) % fromInteger (R.denominator r)++instance Real RatioInt where+    toRational (RatioInt x y) = toInteger x R.% toInteger y++instance RealFrac RatioInt where+    properFraction (RatioInt x y) = let (q, r) = x `quotRem` y+                                    in (fromIntegral q, RatioInt r y)+    truncate       (RatioInt x y) = fromIntegral (x `quot` y)++instance Enum RatioInt where+    succ x = x + 1+    pred x = x - 1++    toEnum n = RatioInt n 1+    fromEnum = truncate++    enumFrom       !n       = n : enumFrom (n + 1)+    enumFromThen   !n !m    = n : enumFromThen m (m + m - n)+    enumFromTo     !n !m    = takeWhile (<= m + 1 / 2) (enumFrom n)+    enumFromThenTo !n !m !p =+        takeWhile predicate (enumFromThen n m)+       where+        mid = (m - n) / 2+        predicate | m >= n    = (<= p + mid)+                  | otherwise = (>= p + mid)

@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain

@@ -0,0 +1,25 @@+name:              ratio-int+version:           0.1+license:           BSD3+author:            Raphael Javaux <raphaeljavaux[at]gmail.com>+maintainer:        Raphael Javaux <raphaeljavaux[at]gmail.com>+synopsis:          Fast specialisation of Data.Ratio for Int.+description:       Fast specialisation of Data.Ratio for Int.+                   .+                   Runs about ten times faster than Data.Int while being half+                   as fast as floating-point types.+category:          Math+cabal-version:     >= 1.9.2+build-type:        Simple+homepage:          https://github.com/RaphaelJ/ratio-int++library+    exposed-modules:    Data.RatioInt++    ghc-options:        -Wall -O2++    build-depends: base                          >= 4           && < 5++source-repository head+  type:     git+  location: https://github.com/RaphaelJ/ratio-int