[molpro-user] Shared memory question in CCSD(T) calculations

[Manhui Wang]

Dear Jani,

The setting
memory, 1000, m
is for one core. If you use N cores, the total memory will be 
N*1000*1000*1000 Words (ie,  N*1000*1000*1000*8 bytes).

For details, please refer to previous list

http://www.molpro.net/pipermail/molpro-user/2010-April/003723.html

Best wishes,
Manhui


On 20/06/13 11:49, Jani Salo wrote:
> Dear Molpro Users,
>
> I have specific question about how memory (or shared memory) is used 
> in the parallel mode.
> I want to run an CCSD(T)/aug-cc-pVDZ calculation of uracil dimer on my 
> small-cluster with 16 cores (with 64 GB of memory)
> It seems that such system needs more than 8GB of memory for 1-core 
> calculation, but it very slow, so when I'm trying to do a parallel 
> calculation on 2 or 2^N cores
> the memory demand is not reduced by that factor. I've changed "memory, 
> 1000, m" option back and forth, but it was not helpful either.
> (I've used compiled mpp-binary Molpro 2012.1 from the website)
> _So Is Molpro distribute used memory over processes or copied the same 
> information? _
> How I can control this behavior?
> I've tried to use -G option (even that in manual written that "is no 
> longer activated") but it was not helpful. I have not found the answer 
> on this question in manual and other sources.
> Can one explain this issue?
>
> Thank you!
>
> Best,
> Jani.
>
>
>
>
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> Molpro-user at molpro.net
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-- 
-----------
Manhui  Wang
School of Chemistry, Cardiff University,
Main Building, Park Place,
Cardiff CF10 3AT, UK

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