module Statistics.Function
(
minMax
, sort
, partialSort
, indexed
, indices
, create
) where
import Control.Exception (assert)
import Control.Monad.Primitive (PrimMonad)
import Data.Vector.Algorithms.Combinators (apply)
import Data.Vector.Generic (unsafeFreeze)
import qualified Data.Vector.Algorithms.Intro as I
import qualified Data.Vector.Unboxed as U
import qualified Data.Vector.Unboxed.Mutable as MU
sort :: (U.Unbox e, Ord e) => U.Vector e -> U.Vector e
sort = apply I.sort
partialSort :: (U.Unbox e, Ord e) =>
Int
-> U.Vector e
-> U.Vector e
partialSort k = apply (\a -> I.partialSort a k)
indices :: (U.Unbox a) => U.Vector a -> U.Vector Int
indices a = U.enumFromTo 0 (U.length a 1)
indexed :: U.Unbox e => U.Vector e -> U.Vector (Int,e)
indexed a = U.zip (indices a) a
data MM = MM !Double !Double
minMax :: U.Vector Double -> (Double , Double)
minMax = fini . U.foldl go (MM (1/0) (1/0))
where
go (MM lo hi) k = MM (min lo k) (max hi k)
fini (MM lo hi) = (lo, hi)
create :: (PrimMonad m, U.Unbox e) => Int -> (Int -> m e) -> m (U.Vector e)
create size itemAt = assert (size >= 0) $
MU.new size >>= loop 0
where
loop k arr | k >= size = unsafeFreeze arr
| otherwise = do r <- itemAt k
MU.write arr k r
loop (k+1) arr