Another one of my rather ambiguous question today, sorry.
Currently I have written some half decent software that has a 'roll your own' RESTful client, which pulls data from twitter. This data is then visualized with a number of particle systems using Open FrameWorks (a framework that works with c++).
My plans for this were to run the software indefinitely on my VPS, and build some kind of front end GUI allowing users to explore the pretty particles and so on. Between the JSON library I am using, C/C++, OpenFrameworks, and freaking Xcode4 I have produced way too many SIGBIRT and GDB errors to care for. I have go to the ends of the virtual world to fix them, and re wrote everything over and over. I even managed to SIGBIRT the openframeworks draw circle method, HAH!
(TL;DR starts here) Ok so anyway I am starting from scratch, looking for a powerful language that can crunch maths and blast through a good set of particles, and run quite well over the longest periods of time. Right now I am thinking about haskell, any ideas?
Thanks in advance all!
Haskell's (or more specifically GHC's) number crunching speed is approaching that of C++ but it's a little way behind. However, it's certainly not terrible, and Haskell's advantages in parallelism may become important. That is, if you write it in straight Haskell first, there's a good chance that it'll be easy to refactor it to run in parallel now or in the future. That isn't so true of C++.
The 'vector' package (on Hackage) would be a good choice for arrays suitable for number crunching. It supports mutable arrays in case that sort of approach is needed. However, if you're prepared to go more on the bleeding edge and your algorithm can be parallelized, you might want to look at the 'repa' package, and for extreme performance on a GPU, take a look at 'Accelerate' (which works but is still categorized as experimental).
The crashes you mention sound like they could be an indication of a bit of complexity in your problem. Where Haskell does well is in managing the complexity of... well, anything. So, if the problem is complex, then Haskell will serve you very well.
The foreign function interface in Haskell is well designed, though you will need to write C glue between Haskell and C++. So, that's another option for your number crunching.
For the web interface, take a look at 'yesod' which is seeing very active development and advertises itself as doing RESTful.