I've also just noticed a lack in the vector library : multidimensional arrays seem to require indirections like in caml, whereas in C or in Data.Ix, there is a way to avoid this. This is especially important for avoiding cache misses with many dimensions, as well as for providing a clean interface. For instance if a 10x10 matrix is initialized unproperly like Data.Vector.replicate 10 $ Data.Vector.replicate 10 0 The result is a total mess. Surely, every programmer knows that a computer has got memory, and that this memory has to be allocated, but from what I understand of haskell, I would expect the interface and the RTS to do it for me. And an integer multiplication, followed by an addition, is way cheaper than accessing uncached memory. Or maybe I do not understand that pipelines, hyperthreading and all that stuff would give you the same result ? El 15/05/2010, a las 20:02, Don Stewart escribió:
pierreetienne.meunier:
Perhaps you can look at the new array packages of the last few years:
* vector
An efficient implementation of Int-indexed arrays (both mutable and immutable), with a powerful loop fusion optimization framework .
http://hackage.haskell.org/package/vector
* Repa
High performance, regular, shape polymorphic parallel arrays.
Indeed... Looks cool ! I suppose I'll have to rewrite a few things. Do you know why they aren't (yet ?) integrated into the hierarchicals ?
Into the libraries distributed with the Haskell Platform, you mean? Because no one has proposed this!
http://trac.haskell.org/haskell-platform/wiki/AddingPackages