[DFTB-Plus-User] On parallel version of DFTB+
Jacek Jakowski
jjakowski at gmail.com
Sun Sep 18 02:26:15 CEST 2016
Most likely you don't have enough memory to fit the 26,000 atoms on
your computer, even if DFTB+ can handle it. Assuming that your
26k atoms are carbons (or similar) you need 80GB to fit a single
matrix (100kbasis) in memory and much more (like 10 times) for a real
calculations.
But then if this fits into your memory, then 100k matrices on 4000
cores takes about 10 hours for a single diagonalization (real case).
It would probably took something like a month to do SCF, and
about half a year for a few MD steps.
I suggest that you decrease the size of cell so that your matrices
are below 32,000.
Jacek
On Fri, Sep 9, 2016 at 1:36 PM, ZHAOHUI HUANG <zuh101 at psu.edu> wrote:
> Hello,
>
> Sorry to bother you if not interested.
>
> I have an issue from running parallel DFTB+. My unit cell contains 26,000 atoms and I just want to relax the structures a few steps. By running the code, I first get output overflow error message, then I increase MAXRECL parameter defined in HSDParser package. It runs indeed. but It failed by SCALAPACK error,
>
> MAXNEIGHBORS: 8847
> iSCC Total electronic Diff electronic SCC error
> Operation failed!
> ppotrf in scalafx_ppotrf_dreal
> Info: 23233
>
>
> Is there any code developer who is familiar with this part of code? thanks.
>
>
> ZhaoHui Huang,
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