-{-# OPTIONS -fparr #-}
+{-# OPTIONS_GHC -fparr #-}
--- $Id: PArr.hs,v 1.2 2002/02/12 10:50:37 simonmar Exp $
---
--- Copyright (c) [2001..2002] Manuel M T Chakravarty & Gabriele Keller
+-----------------------------------------------------------------------------
+-- |
+-- Module : GHC.PArr
+-- Copyright : (c) 2001-2002 Manuel M T Chakravarty & Gabriele Keller
+-- License : see libraries/base/LICENSE
+--
+-- Maintainer : Manuel M. T. Chakravarty <chak@cse.unsw.edu.au>
+-- Stability : internal
+-- Portability : non-portable (GHC Extensions)
--
-- Basic implementation of Parallel Arrays.
--
---- DESCRIPTION ---------------------------------------------------------------
---
-- This module has two functions: (1) It defines the interface to the
-- parallel array extension of the Prelude and (2) it provides a vanilla
-- implementation of parallel arrays that does not require to flatten the
--
module GHC.PArr (
- [::], -- abstract
+ -- [::], -- Built-in syntax
mapP, -- :: (a -> b) -> [:a:] -> [:b:]
(+:+), -- :: [:a:] -> [:a:] -> [:a:]
sumP = foldP (+) 0
productP :: (Num a) => [:a:] -> a
-productP = foldP (*) 0
+productP = foldP (*) 1
maximumP :: (Ord a) => [:a:] -> a
maximumP [::] = error "Prelude.maximumP: empty parallel array"
-- Ideally, we would like `enumFromToP' and `enumFromThenToP' to be members of
-- `Enum'. On the other hand, we really do not want to change `Enum'. Thus,
-- for the moment, we hope that the compiler is sufficiently clever to
--- properly fuse the following definition.
+-- properly fuse the following definitions.
enumFromToP :: Enum a => a -> a -> [:a:]
enumFromToP x y = mapP toEnum (eftInt (fromEnum x) (fromEnum y))
mapP toEnum (efttInt (fromEnum x) (fromEnum y) (fromEnum z))
where
efttInt x y z = scanlP (+) x $
- replicateP ((z - x + 1) `div` delta - 1) delta
+ replicateP (abs (z - x) `div` abs delta + 1) delta
where
delta = y - x
-- unlike standard Haskell arrays, this value represents an
-- internal error
--- actually loop body of `loop'
+-- actual loop body of `loop'
--
-- * for this to be really efficient, it has to be translated with the
-- constructor specialisation phase "SpecConstr" switched on; as of GHC 5.03