[Pw_forum] shared memory

Paolo GIANNOZZI giannozz at nest.sns.it
Fri Nov 7 10:32:12 CET 2003


On Thu, 06 Nov 2003 17:49:20 +0000
 Jonathan Breeze <breezejd at lsbu.ac.uk> wrote:

> Would I be correct in thinking that PW uses shared memory
> in its MPI usage ???

I would say that yiou aren't. PW starts N independent
processes that communicate via calls to MPI libraries. 
Each process has its own set of variables and knows 
nothing about other precesses' variables. Variables 
that take little memopry are replicated, those that 
take a lot of memory (wavefunctions, G-vectors, R-space
grid) are distributed

Paolo



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