Re: [Swarm-Modelling] ABMs on Graphical Processor Units

[Russell Standish]

On Thu, Dec 27, 2007 at 10:56:55PM -0700, Marcus G. Daniels wrote:
> Russell Standish wrote:
> >The blocks need to be implementable in SIMD hardware, which pretty
> >much rules out the sort of higher level functionality you're talking
> >about. 
> Not really, the Cell SDK has a complete GCC target (e.g. working 
> Objective C and C++) for both the front end (PPU) and back end (SPU) 
> processors.  As far as RPC infrastructure goes, it happens that when a C 
> routine is called on a SPU for a Unix system call, that system call is 
> actually a RPC back to the PPU.   Unfortunately, OpenMP in GCC (gomp) 
> doesn't work out of the box because there are two different instruction 
> sets (one 64 bit for the PPU) and (32 bit for the SPU).  But there's a 
> low level library for messaging (libspe) and even a IDL stubber for 
> higher level stuff:
> 
> http://moss.csc.ncsu.edu/~mueller/cluster/ps3/idl.pdf

You are probably right on the Cell. I haven't studied the
architecture, nor the software environment.  There is a possibility of
me getting involved in a Cell based project at CSU Bathurst - depends
on funds, that is one problem with the private sector, you often need
to do what your customers want :(

It sounds like one could do MPI on the Cell, however, which would allow
Graphcode-based applications written in EcoLab to work.

> 
> Of course, additional runtime support would be needed to implement the 
> idea I mentioned, but it's not like it is necessary to use only assembly 
> or compiler intrinsics to get off the ground.  Even NVidia GPUs now have 
> a C-like language (CUDA).
> 

GPUs are a different kettle of fish, as they are definitely SIMD based
(apply the same instruction to an array of pixels). 

> >Other possibilities include artificial neural networks,
> >or fuzzy logic inference engines that could be used to implement agent
> >behaviour.
> >  
> I was thinking some kind of optimization package would make a lot of 
> sense for GPUs or the Cell.  Any kind of procedure that had lots of 
> candidates at once -- like a genetic program or a parallel tempering 
> procedure.

That too. The problem is that optimisation usually involves callbacks
into the optimisation function, which may be a full blown ABM. 

> 
> Marcus
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