RE: [pooma-dev] Status of Particles and Parallelism

[Julian C. Cummings]

Hello,

I've been away on vacation for a while, just now getting back to my e-mail.
I'm a bit puzzled by this.  The whole point of Cheetah was to provide a
uniform parallel interface, so that one could use MPI or a SHMEM-like system
interchangeably without worrying about the exact implementation details of
the parallelism.  So I don't understand how the particles code could work
with Cheetah but not with MPI.

In any case, my recollection is that the PatchSwapLayout code was used to
exchange info between processors sharing a virtual node boundary about how
many particles would be coming or going.  Once this info is exchanged, the
actual particle data can be efficiently exchanged using the Cheetah
messaging protocols.  That's the idea, anyway.  I don't know that I would be
able to help you diagnose specific bugs/problems in the code at this point,
having been away from it for so very long, but feel free to fire questions
at me and I will do what I can to help.

Regards, Julian C.

Dr. Julian C. Cummings
Staff Scientist, CACR/Caltech
(626) 395-2543
address@hidden
 

> -----Original Message-----
> From: Richard Guenther [mailto:address@hidden 
> Sent: Saturday, August 14, 2004 7:09 AM
> To: Jeffrey D. Oldham
> Cc: address@hidden; address@hidden
> Subject: Re: [pooma-dev] Status of Particles and Parallelism
> 
> 
> Jeffrey D. Oldham wrote:
> > Richard,
> > 
> >    Last month you made progress on particles in the Pooma CVS
> > repository.  Steve Nolen wishes to use particles in the 
> Pooma repository 
> > code and MPI for his work.  What is the current state of 
> the particles 
> > codes with MPI.  As an alternate, using Cheetah will be 
> acceptable.  
> > Thanks for the information.
> > 
> 
> Sorry for the late reply, I was on vacation.  Parallel 
> Particles are not 
> supported with MPI as I was not able to understand what 
> PatchParticleSwapLayout (or whatever it is called).  If 
> anyone provides 
> me with some explanation, I'll happily look at what is missing.
> 
> Btw. I have some Cheetah fixes myself, I can collect these 
> together and 
> maybe we could provide at least a patch for download along 
> the cheetah 
> tarball.
> 
> Richard.
>