On Tue, 2006-11-28 at 15:10 +0300, Bulat Ziganshin wrote:
Hello Niko,
Tuesday, November 28, 2006, 1:42:10 PM, you wrote:
I personally find doing higher order functions with IO extremely difficult, and the resulting compiler errors are often downright scary. But this is probably a direct consequence my rather limited understanding of the monadic operators that the do notion hides. It seems that one has to be /very/ good in Haskell before one can do IO effectively.
i will say that one should be very good in general program optimization and know a few haskell-specific tricks, such as avoiding laziness and boxing
optimization is my lovely problem, so i can help you somewhat. first, look at http://haskell.org/haskellwiki/Performance page. second, look at sources of ByteString (FPS) library - because it both shows efficient programming style and can be used for your sound processing
inefficient beyond imagination. The overhead of one list element is
8 bytes on 32-bit system
Actually it's 12 bytes. 4 for the cell header, 4 for the head pointer and 4 for the tail pointer. On a 64bit machine it is double that of course.
probably larger than the size of the element itself (16 to 32 bit integers) and a new list would have to be generated every time more data is read from the hard disk. So the garbage collector would be working really hard all the time. And this list would have to be converted into an IO buffer for passing it to the C sound API anyway. These were the reasons why I went for the IOUArray way to begin with. For this particular problem, probably the most natural and efficient solution is to have a static buffer in memory to which data is read from the hard drive and which is then passed to the sound API for playback. For me, this seems the best way to do the job.
it seems that you are ideal consumer for unboxed parallel arrays or extended ByteStrings (WordStrings :)
we can ask Donald and Duncan whether they interested in implementing such extension?
Spencer Janssen implemented a variant on ByteString for arbitrary instances of the Storable class. Duncan