Hi Mukesh, Below is a naive implementation of converting `[[(Int,Double)]]' to `PArray (PArray (Int, Double))' . There's no instance for `PA [a]', I've explicitly separated the inner and outer conversion. Though, when reading data from a file and converting, it might be better to use `hGet' in: http://hackage.haskell.org/packages/archive/dph-prim-par/0.5.1.1/doc/html/Da... -- module Main where import Data.Array.Parallel import Data.Array.Parallel.PArray () import qualified Data.Array.Parallel.PArray as P mat_li :: [[(Int, Double)]] mat_li = [ zip [1..] [ 1, 2, 3, 0, 0, 0, 0, 0, 4 ] , zip [1..] [ 0, 0, 0, 0, 0, 0, 0, 0, 0 ] , zip [1..] [ 0, 0, 0, 0, 0, 0, 1, 2, 0 ] ] mat_pa_1 :: PArray (PArray (Int, Double)) mat_pa_1 = P.fromList (fmap P.fromList mat_li) mat_pa_2 :: PArray (PArray (Int, Double)) mat_pa_2 = conv_outer (conv_inner mat_li) conv_inner :: P.PA a => [[a]] -> [PArray a] conv_inner = map P.fromList conv_outer :: P.PA a => [PArray a] -> PArray (PArray a) conv_outer xs = case xs of [] -> P.empty (x:xs) -> P.singleton x P.+:+ conv_outer xs main :: IO () main = -- Printing `mat_pa_1' shows an error: -- -- > No instance nor default method for class operation -- > Data.Array.Parallel.PArray.PData.fromListPR -- -- print mat_pa_1 print mat_pa_2 ---- Hope this well help. Regards, -- Atsuro Hoshino On Thu, Jan 19, 2012 at 4:47 AM, mukesh tiwari wrote:

Hello all I am trying to convert List of Lists ( [[(Int , Double )]] ) into PArray ( PArray ( Int , Double )) but getting run time error. This code works fine and print list of PArray ( Int , Double ) but when i put print $ P.fromList ( map P.fromList c ) then i am getting runtime error. It says "Main: Data/Array/Parallel/PArray/PDataInstances.hs:337:10-30: No instance nor default method for class operation Data.Array.Parallel.PArray.PData.fromListPR". Could some one please tell me how to resolve this issue. Thank you

--import ParallelMat import Data.List import System.Environment import Data.Array.Parallel import qualified Data.Array.Parallel.PArray as P

processMatrix :: [ [ Double ] ] -> [ [ Double ] ] -> [ ( [ ( Int , Double ) ] , [ ( Int , Double ) ]) ] processMatrix [] [] = [] processMatrix ( x : xs ) ( y : ys )   | ( all ( == 0 ) x )  Prelude.|| (  all ( == 0 ) y ) = processMatrix xs ys   | otherwise = ( filter ( \( x , y ) -> y /= 0 ) . zip [ 1..]  $ x ,filter (  \( x , y ) -> y /= 0 ) . zip [1..] $ y  ) : processMatrix xs ys

main = do     [ first , second ] <- getArgs     a <- readFile first     b <- readFile second     let a' = transpose . tail . map ( map ( read :: String -> Double ) . words ) . lines $ a         b' = tail . map ( map ( read :: String -> Double ) . words ) . lines $ b         ( c , d )   = unzip $ processMatrix a' b'     print $   (  map P.fromList c )    --print d

Macintosh-0026bb610428:Haskell mukesh$ ghc --make  -Odph -fdph-par  Main.hs [1 of 1] Compiling Main             ( Main.hs, Main.o ) Linking Main ... Macintosh-0026bb610428:Haskell mukesh$ ./Main  A.in A.in [fromList<PArray> [(1,1.0),(6,1.0)],fromList<PArray> [(4,11.0),(9,11.0)],fromList<PArray> [(1,4.0),(4,2.0),(6,4.0),(9,2.0)]]

Putting print $ P.fromList ( map P.fromList c )

Macintosh-0026bb610428:Haskell mukesh$ ghc --make  -Odph -fdph-par  Main.hs [1 of 1] Compiling Main             ( Main.hs, Main.o ) Linking Main ... Macintosh-0026bb610428:Haskell mukesh$ ./Main  A.in A.in Main: Data/Array/Parallel/PArray/PDataInstances.hs:337:10-30: No instance nor default method for class operation Data.Array.Parallel.PArray.PData.fromListPR

Input file A.in 10 10 1 2 3 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 11 2 0 1 2 0 0 0 0 0 0 0 1 2 3 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 11 2 0 1 2 0 0 0 0 0 0 0 _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe