[Haskell-cafe] State Variables

minh thu noteed at gmail.com
Mon May 29 06:01:29 EDT 2006


hi,

Bulat, i quote the doc for Data.Array.Storable :
"It is similar to IOUArray but slower. Its advantage is that it's
compatible with C."
So you speak about Storable because Matthew wants to use BLAS and LAPACK ?

Cheers,
mt

2006/5/29, Bulat Ziganshin <bulat.ziganshin at gmail.com>:
> Hello Matthew,
>
> Monday, May 29, 2006, 1:38:38 AM, you wrote:
>
> > The third and final concern is the point of this post.  How does one
> > handle state efficiently in Haskell?
> > I've seen the various state monads and gained a superficial enough
> > understanding to be concerned about
> > how useful they are, for the following reason:
>
> > I would like to aggregrate a large number of state variables (possibly
> > in the hundreds of variables) into a few
> > data structures.  These structures would not only contain basic variable
> > types, but probably some rather large
> > mutable arrays.  So lets say I have such a structure called world and I
> > wish to update just 1 entry.  If I do
> > w=world{entry=newentry}, the entire enormous world structure is copied to w.
>
> use RealWorld :)  IORef and StorableArray are you best friends. after
> all, it's not good idea to work with StorableArray otherwise than
> via the IO monad. i think you should create separate thread for each
> part of your simulation and send data between them through Channels
>
> --
> Best regards,
>  Bulat                            mailto:Bulat.Ziganshin at gmail.com
>
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