[CP2K:255] Re: flags for reducing memory consumption for quickstep and quickstep QM/MM

Teodoro Laino teodor... at gmail.com
Tue Sep 11 16:40:02 UTC 2007

Very good Axel,

let me point the situation:

there's a keyword RS_GRID in the EWALD section (both in MM and DFT)  
but that one affects only the EWALD calculations.
In particular EWALD in MM should be quite clear.. EWALD in DFT is  
used for DFTB.

the other place where there's a RS_GRID keyword is in the &QS section  
and this should affect the memory in your case.

if you use RS_GRID in the EWALD, it is properly parsed but has no  
effect on your GPW calculation.


On 11 Sep 2007, at 18:24, Axel wrote:

> i can confirm this on x86_64 using intel 10, OpenMPI, and MKL.
> i tested with FIST. i noticed, however, that there are two entries
> for ewald one in /FORCE_EVAL/DFT/POISSON/EWALD and one in
> /FORCE_EVAL/MM/POISSON/EWALD and both claim to be applicable only
> to classical atoms. it would be nice if somebody could clarify this.
> out of the three EWALD options, SPME (which i have been using already)
> seems to be the least memory hungry followed by plain EWALD and PME.
> what strikes me odd, is that in the communication summary, there are
> the exact same number of calls to the MP_xxx subroutines in both
> cases.
> i would have expected that in the distributed case, there is a
> (slightly?)
> different communication pattern as with replicated. could it be, that
> the flag is not correctly handed down? it appears in the restart
> files,
> so i assume it is parsed ok.

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