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

[Russell Standish]

On Fri, Dec 28, 2007 at 09:40:38AM -0700, Marcus G. Daniels wrote:
> Russell Standish wrote:
> >It sounds like one could do MPI on the Cell, however, which would allow
> >Graphcode-based applications written in EcoLab to work.
> Unfortunately, the ELF text section of OpenMPI is around 5 times too big 
> to fit on a Cell local store.   It might be possible to strip it down, 
> but after all that work you'd probably have something that looked a lot 
> like libspe2:

All you need to do is link statically, rather than dynamically. This
happens by default when you use MPICH, for instance. Then you are just
loading up the parts that you use. But seriously, how much local
memory do you get on a cell local store? If it is not enough to store
a few megabytes of dynamic libraries, it will not be enough to do any
serious ABM simulation, which tends to need 100s of MB.

> 
> http://www-01.ibm.com/chips/techlib/techlib.nsf/techdocs/1DFEF31B3211112587257242007883F3/$file/SPE_Runtime_Management_API_v2.2.pdf
> >
> >GPUs are a different kettle of fish, as they are definitely SIMD based
> >(apply the same instruction to an array of pixels). 
> >  
> Nonetheless..
> 
> http://developer.nvidia.com/object/cuda.html
> http://developer.download.nvidia.com/compute/cuda/1_1/NVIDIA_CUDA_Programming_Guide_1.1.pdf
> 
> It's also worth noting that development kits for field programmable gate 
> arrays  (FPGA) also have C dialect languages.
> 

I never mentioned anything about having to program in
assembler. However, it is still a significant constraint to program in
a vector way - it works well for some things, like vectors, and not so
well for other things that require a lot of branching.

> http://en.wikipedia.org/wiki/Impulse_C
> 
> For those times that you really want to be able to optimize over the 
> parameter space for an ABM.  :-)
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