Thanks - I'll probably wait for the next release.
On 1 Jan 2013, at 19:48, Simon Peyton-Jones
I think the patch did get into 7.6.2 (which is about to be released) though.
I don't think there's a workaround, except by not using External Core, or not using Integer literals (use Ints?). Sorry.
Simon
| -----Original Message----- | From: glasgow-haskell-users-bounces@haskell.org [mailto:glasgow-haskell-users- | bounces@haskell.org] On Behalf Of Dominic Steinitz | Sent: 26 December 2012 18:14 | To: glasgow-haskell-users@haskell.org | Subject: Is there a workaround for this bug? | | AFAICT this bug fix http://hackage.haskell.org/trac/ghc/ticket/7239 did not make | it into 7.6.1. Also I am happily working on the Haskell Platform with 7.4.1 and I'd | rather avoid upgrading if possible. | | Is there a workaround? I've attached my code below along with the error message | (which is the same as in the above bug report). I'm rather hoping I won't have to | build HEAD. | | Thanks, Dominic. | | bash-3.2$ ghc -fext-core --make Test.hs | [1 of 1] Compiling Main ( Test.hs, Test.o ) | ghc: panic! (the 'impossible' happened) | (GHC version 7.4.1 for x86_64-apple-darwin): | MkExternalCore died: make_lit | | {-# LANGUAGE FlexibleContexts #-} | | {-# OPTIONS_GHC -Wall -fno-warn-name-shadowing -fno-warn-type-defaults #-} | | import Data.Array.Repa as Repa | import Data.Array.Repa.Eval | import Control.Monad | | r, sigma, k, t, xMax, deltaX, deltaT :: Double | m, n :: Int | r = 0.05 | sigma = 0.2 | k = 50.0 | t = 3.0 | m = 80 | xMax = 150 | deltaX = xMax / (fromIntegral m) | n = 800 | deltaT = t / (fromIntegral n) | | data PointedArrayU a = PointedArrayU Int (Array U DIM1 a) | deriving Show | | f :: PointedArrayU Double -> Double | f (PointedArrayU j _x) | j == 0 = 0.0 | f (PointedArrayU j _x) | j == m = xMax - k | f (PointedArrayU j x) = a * x! (Z :. j-1) + | b * x! (Z :. j) + | c * x! (Z :. j+1) | where | a = deltaT * (sigma^2 * (fromIntegral j)^2 - r * (fromIntegral j)) / 2 | b = 1 - deltaT * (r + sigma^2 * (fromIntegral j)^2) | c = deltaT * (sigma^2 * (fromIntegral j)^2 + r * (fromIntegral j)) / 2 | | priceAtT :: PointedArrayU Double | priceAtT = PointedArrayU 0 (fromListUnboxed (Z :. m+1) | [ max 0 (deltaX * (fromIntegral j) - k) | j <- [0..m] ]) | | coBindU :: (Source U a, Source U b, Target U b, Monad m) => | PointedArrayU a -> (PointedArrayU a -> b) -> m (PointedArrayU b) | coBindU (PointedArrayU i a) f = computeP newArr >>= return . PointedArrayU i | where | newArr = traverse a id g | where | g _get (Z :. j) = f $ PointedArrayU j a | | testN :: Int -> IO (PointedArrayU Double) | testN n = h priceAtT | where | h = foldr (>=>) return | (take n $ Prelude.zipWith flip (repeat coBindU) (repeat f)) | | main :: IO () | main = do r <- testN n | putStrLn $ show r | | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users