Hello Chris, Friday, February 2, 2007, 4:44:37 PM, you wrote:
If I have two identical STUArrays (same type and bounds) then what is the most efficient way to overwrite the data in the destination with the data in the source? Does this work for STArrays?
Is there a way to avoid the long loop?
forM_ (range b) $ \index -> readArray source index >>= writeArray destination index
the topic of efficient looping over arrays is briefly covered in http://haskell.org/haskellwiki/Modern_array_libraries
Is there a GHC only solution?
yes, use "unsafeCoerce# memcpy": module Data.Array.Base where ... #ifdef __GLASGOW_HASKELL__ thawSTUArray :: Ix i => UArray i e -> ST s (STUArray s i e) thawSTUArray (UArray l u arr#) = ST $ \s1# -> case sizeofByteArray# arr# of { n# -> case newByteArray# n# s1# of { (# s2#, marr# #) -> case unsafeCoerce# memcpy marr# arr# n# s2# of { (# s3#, () #) -> (# s3#, STUArray l u marr# #) }}} foreign import ccall unsafe "memcpy" memcpy :: MutableByteArray# RealWorld -> ByteArray# -> Int# -> IO () #endif /* __GLASGOW_HASKELL__ */ -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com