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| From: | James Crotinger |
| Subject: | RE: [pooma-dev] simple pooma question |
| Date: | Wed, 17 Jul 2002 09:41:58 -0600 |
> Sorry if these are simple questions, but I am having quite a
> lot of difficulty trying to understand what POOMA does during
> its parallel execution. I have done some parallel programming
> before, but here everything is hidden!
That was the point. (Hiding parallelism, not causing you difficulty 8-)
> If a piece of code has both a serial component and a parallel
> component, and one is executing it in a distributed
> environment, does every copy of the code run the serial
> component, or does POOMA only make one node execute the
> serial component. Similarly, are arrays which are not
> declared as distributed, then exist as identical copies on each node?
Under normal operation, POOMA is basically SPMD, so yes, the serial code runs in every process. If a threaded evaluator is used, then the serial code runs in the main thread of every process, but not in the worker threads.
>
> Also, where can I look to better understand the parallel
> behaviour of POOMA?
I'm not sure what the state of the tutorials are. The nitty-gritty is not documented anywhere that I'm aware of. We tried to do a good job of commenting the source, so there is always that. A high level design document would have been good, especially for an open-source development model. When this was being developed at the lab, there were 8-10 people working closely together, having weekly meetings, etc., and some of the stuff that was well known to all just never got written down.
Jim
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