[CP2K:8806] very long calculation time

[hut... at chem.uzh.ch]

Hi

is your 'long' simulation time caused by:

- slow convergence of geometry optimization
- slow convergence of SCF
- high CPU time per SCF cycle?

To improve CPU time per SCF I would suggest (guessing without 
knowing your full input)
- use only MOLOPT-SR basis sets
- reduce EPS_DEFAULT to 1.e-10
- Preconditioner -> FULL_SINGLE_INVERSE

Do you really need LSD?

regards

Juerg Hutter
--------------------------------------------------------------
Juerg Hutter                         Phone : ++41 44 635 4491
Institut für Chemie C                FAX   : ++41 44 635 6838
Universität Zürich                   E-mail: hut... at chem.uzh.ch
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
---------------------------------------------------------------

-----cp... at googlegroups.com wrote: -----To: cp2k <cp... at googlegroups.com>
From: Amin 
Sent by: cp... at googlegroups.com
Date: 03/13/2017 10:28AM
Subject: [CP2K:8806] very long calculation time

Hi all,I am trying to calculate the adsorption energy of co2 on Tio2 surface (with 192 atoms in my supercell). but the problem is that it takes too long time to be calculated. I'm using 80 processors (2.8 GHz - each) but as I set the wall time for 7 days, it reached that wall time and calculations stopped. I have done similar calculations for fewer atoms (48,98) in super cell but in those cases (even with fewer CPUs) it takes at most 1 day to calculate everything. Because I'm a beginner in CP2K, I don't have any idea weather this amount of time for calculation is reasonable. I have attached critical parts of my input file. I will be grateful if someone gives a comment regarding my question.- Any suggestion for decreasing the calculation time with the same number of atoms is warmly appreciated.. :)
&GLOBAL  PROJECT  Ch  RUN_TYPE GEO_OPT  PRINT_LEVEL LOW  EXTENDED_FFT_LENGTHS&END GLOBAL
&FORCE_EVAL  METHOD Quickstep       &DFT    BASIS_SET_FILE_NAME  BASIS_MOLOPT    POTENTIAL_FILE_NAME  GTH_POTENTIALS    LSD    CHARGE 0    MULTIPLICITY 1    &MGRID        CUTOFF 800        REL_CUTOFF 60    &END MGRID    &QS        METHOD GPW        EPS_DEFAULT 1.0E-12    &END QS    &POISSON        PERIODIC XYZ    &END POISSON    &SCF                            SCF_GUESS ATOMIC      EPS_SCF 1.0E-6      MAX_SCF 100      &OT        PRECONDITIONER FULL_ALL        MINIMIZER CG      &END OT      &OUTER_SCF        MAX_SCF 20        EPS_SCF 1.0E-6      &END OUTER_SCF    &END SCF    &XC                  &XC_FUNCTIONAL PBE      &END XC_FUNCTIONAL      &VDW_POTENTIAL        DISPERSION_FUNCTIONAL PAIR_POTENTIAL        &PAIR_POTENTIAL                TYPE DFTD3(BJ)                REFERENCE_FUNCTIONAL PBE                CALCULATE_C9_TERM .FALSE.                PARAMETER_FILE_NAME dftd3.dat                R_CUTOFF 15.0        &END PAIR_POTENTIAL      &END VDW_POTENTIAL    &END XC  &END DFT
  &SUBSYS    &CELL      ABC 15.138 15.138 30.0000      PERIODIC XYZ     &END CELL    &TOPOLOGY      COORD_FILE_FORMAT XYZ      COORD_FILE_NAME  ./Anatase001-192.xyz    &END
&END FORCE_EVAL&MOTION        &GEO_OPT          OPTIMIZER BFGS          MAX_FORCE 4.50000000E-004        &END        &CONSTRAINT          &FIXED_ATOMS                LIST 0..95          &END FIXED_ATOMS        &END CONSTRAINT&END MOTION




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