[Wien] Problems with hybrid calculation

tran at theochem.tuwien.ac.at tran at theochem.tuwien.ac.at
Tue Mar 3 10:16:31 CET 2015


I still don't understand why the script run_lapw does not find the ibz and
fbz files. Maybe not related to this, what are you specifying for the
SCRATCH directory? With hybrid functionals it is mandatory to use ./
(the directory of the calculation) for SCRATCH because of the files
case.vectorhf(_old).

It is difficult to say for the computation time, but it will certainely
be (too?) huge for a self-consistent calculation. The problem with
Hartree-Fock is that it consists of two loops over orbitals which makes
the calculations very expensive for plane-wave type basis sets.
Nevertheless, you have to consider a few points:

-Do the calculation with only one k-point. Maybe the accuracy is enough,
in particular if your system is non-metallic.

-Use the onsite-hybrid functionals (as cheap as LDA/GGA) if your system
contains strongly localized d- or f-electrons.

-Use a proper .machines file. It is useless to have more lines in
.machines than the number of k-points in the IBZ. For one k-point
calculation this should be only one line (specifying the list of 96
processors for the MPI). More details in the UG.

-If you are interested only in the electronic structure, then you
should consider the diagonal approximation (-diaghf), see the UG,
which consists of only one (and faster) iteration.

F. Tran

On Tue, 3 Mar 2015, Paul Fons wrote:

> Hi I did run init_hf_lapw and I saw no sign of errors upon running it, however, I ran it from the web interface the first time.  I just
> restarted the calculation using bash and have confirmed the ibz and fbz files exist.The reason that I am interested in hybrid mode is that
> I actually have 96 processors available with infiniband interconnects.  Is a 96 atom system too expensive to run with PBE0 even with 96
> cores? How much time should I expect such a calculation to take?
> 
> Paul Fons 
> 
>
>       On Mar 3, 2015, at 4:56 PM, tran at theochem.tuwien.ac.at wrote:
> 
> Hi,
> 
> init_hf_lapw executes run_kgenhf_lapw which creates the files
> case.klist_ibz, case.klist_fbz, case.kgen_ibz and case.kgen_fbz.
> So, I don't understand why they are not present in your directory.
> Are you sure that init_hf_lapw ran without problems?
> 
> Beside this, I really think that you should forget about running hybrid
> functionals for 96 atoms, in particular with this small number of
> processors (unless you are willing to wait until retirement).
> Depending on the system/properties that you are considering,
> the use of a GGA functional maybe give results which are fairly reliable.
> 
> F. Tran
> 
> On Tue, 3 Mar 2015, Paul Fons wrote:
>
>       Hi All,
>         I am trying to calculate the density of states of a small cluster of 96 atoms.  I am using the hybrid mpi/k-point
>       mode.  The
>       calculation ran to completion without problems for PBE.  My .machines file is listed below.  As the cluster is amorphous
>       and
>       roughly cubic in shape, I used a 2x2x2 MP mesh.  I then attempted to use the PBE0 hybrid functional.  After using the
>       init_hf_lapw script, I started the SCF loop.  The calculation ran for several hours and then stopped.  I have attached
>       the STDOUT
>       output below.  I am using intel ifort (15) as well as the intel mpi environment.  I do have a scratch directory set up
>       on this
>       same node.
>        These calculations were run on a single 24 core machine.  I have five of these machines connected by Infiband and would
>       like to
>       scale up the calculation to use several nodes if I can find and solve the hybrid problem as I am aware of the cost of
>       the PBE0
>       calculations.
>       Any advice?
>       Best wishes,
>       Paul Fons
>       .machines
>       lapw0:localhost:24
>       1:localhost:2
>       1:localhost:2
>       1:localhost:2
>       1:localhost:2
>       1:localhost:2
>       1:localhost:2
>       1:localhost:2
>       1:localhost:2
>       1:localhost:2
>       1:localhost:2
>       1:localhost:2
>       1:localhost:2
>       granularity:1
>       extrafine:1
>       STDOUT
>        LAPW0 END
>        LAPW0 END
>       cp: cannot stat `aCGT.kgen_fbz': No such file or directory
>       cp: cannot stat `aCGT.klist_fbz': No such file or directory
>        LAPW1 END
>       mv: cannot stat `aCGT.vector': No such file or directory
>       cp: cannot stat `aCGT.kgen_ibz': No such file or directory
>       cp: cannot stat `aCGT.klist_ibz': No such file or directory
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>        LAPW1 END
>       cp: cannot stat `aCGT.kgen_fbz': No such file or directory
>       cp: cannot stat `aCGT.klist_fbz': No such file or directory
>       mv: cannot stat `aCGT.vectorhf_old': No such file or directory
>       forrtl: severe (24): end-of-file during read, unit 1001, file /usr/local/share/wien2k/Fons/aCGT/031
>       Image              PC                Routine            Line        Source             
>       lapw2c             0000000000648027  Unknown               Unknown  Unknown
>       lapw2c             0000000000669FF3  Unknown               Unknown  Unknown
>       lapw2c             0000000000482FEE  outp_                     180  outp.f
>       lapw2c             00000000004701EC  l2main_                  2125  l2main_tmp_.F
>       lapw2c             000000000047CEA5  MAIN__                    607  lapw2_tmp_.F
>       lapw2c             000000000040407E  Unknown               Unknown  Unknown
>       libc.so.6          000000343F61ED5D  Unknown               Unknown  Unknown
>       lapw2c             0000000000403F89  Unknown               Unknown  Unknown
>       >   stop error
> 
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> 
> Dr. Paul FonsSenior Research Scientist
> Functional Nano-phase-change Research Team
> Nanoelectronics Research Institute
> National Institute for Advanced Industrial Science & TechnologyMETI
> AIST Central 4, Higashi 1-1-1Tsukuba, Ibaraki JAPAN 305-8568
> tel. +81-298-61-5636fax. +81-298-61-2939
> email: paul-fons at aist.go.jp
> The following lines are in a Japanese font
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