module Main where

import System.Environment
import Control.Parallel.Eden
import Control.Parallel.Eden.MapReduce
-- import MapRedSkels
import Control.Parallel.Eden.Auxiliary
-- import MapSkels
-- import Auxiliary

main :: IO ()
main = getArgs >>= \ (n:_) ->
       putStrLn $ show (cpi (read n))

-- compute pi using integration
cpi   :: Integer -> Double
cpi n =  offlineParMapRedr (+) 0 (f.index) [1..n]  / fromInteger n
  where
    f       :: Double -> Double
    f x     =  4 / (1 + x*x)
    index   :: Integer -> Double
    index i = (fromInteger i - 0.5) / fromInteger n 

-- test n = mapFarmS (f.index) [1..n]
    
{-
parMapRed :: (Trans a, Trans b) => 
             (b -> b -> b) -> b -> (a -> b) -> [a] -> b
parMapRed g e f 
  = if noPe == 1 then mapRed g e f else
     oFarm (splitIntoN noPe) (foldr g e) (mapRed g e f) 

oFarm :: (Trans a, Trans b) => 
         (t -> [a]) -> ([b] -> c) -> (a -> b) -> t -> c
oFarm distribute combine f xs 
  = combine $ parMap (\ i ->  f ((distribute xs)!!i)) [0..noPe-1]


newtype LBox a = LBox {unLBox :: a}
instance Trans a => Trans (LBox a)
instance NFData a => NFData (LBox a)

parMapRed2 :: (Trans a, Trans b) => 
             (b -> b -> b) -> b -> (a -> b) -> [a] -> b
parMapRed2 g e f 
  = if noPe == 1 then mapRed g e f  else
    (foldr g e) . (parMap (mapRed g e f)) . (splitIntoN noPe)

parMapRed3 :: (Trans a, Trans b) => 
             (b -> b -> b) -> b -> (a -> b) -> [a] -> b
parMapRed3 g e f xs
  = if noPe == 1 then mapRed g e f xs else
    foldr g e $ 
      parMap (\ i -> mapRed g e f (splitIntoN noPe xs!!i)) [0..noPe-1]



mapRed :: (b -> c -> c) -> c -> (a -> b) -> [a] -> c
mapRed g e f = (foldr g e) . (map f)
 
-}