Hi,

I am trying to run a phonon calculation on a system containing around 300 atoms in order to obtain its full Hessian matrix. Unfortunately wall time on our supercomputer architecture is limited to 48 hrs, hence the calculation does not finish in time when run on 16 nodes (384 cores). Since I am using finite differences, it should be possible to parallelise this job efficiently and run it on a big number of cores. Is this simply a matter of increasing the number of cores in this case? The system also contains some symmetry, so it might be useful to use IBRION=6 instead? Perhaps somebody can give me some advise, I am pretty certain that this should work somehow.

Below is my INCAR file.

Thanks

Tobias

General:

SYSTEM = [Rh-dcype-exo-nba][BArCl]

! if enough K-points are present -5 should be used

ISMEAR = 0 ! 0: Gaussian -> semicond/insulator ; 1-N: MP; -5: Tetra+Blochl -> metal/very accurate energy/forces

SIGMA = 0.05

EDIFF = 1.0E-7

PREC = Normal ! to make ROPT=2.0E-4 for LREAL=Auto

LREAL = Auto ! cheaper for large cell's we are using

ENCUT = 600 !

ISYM = 2 # use symmetry as done for PAW PP

NELMIN = 8

LWAVE = .FALSE.

LCHARG = .FALSE.

! LVTOT = .TRUE. ! Write LOCPOT file for Toon

! LVHAR = .TRUE. ! but LOCPOT without exchange and correlation contribution for forcefields Toon

VOSKOWN = 1 ! important for GGA (PW91) for interpolation of XC...since we only use PBE=switch on (LDA: VOSKOWN=0)

LASPH = .TRUE. ! For VASP.5.X the aspherical contributions are properly accounted for in the Kohn-Sham potential

! as well. This is essential for accurate total energies and band structure calculations for f-elements

! (e.g. ceria), all 3d-elements (transition metal oxides), and magnetic atoms in the 2nd row (B-F atom),

! in particular if LDA+U or hybrid functionals or meta-GGAs are used, since these functionals often result

! in aspherical charge densities.

Van der Waals Interaction (vasp 5.3.3 patched verion):

IVDW = 12 ! switches between 0:off, 1: DFT-D3 and 2: TS-VDW (default=1)

dynamic:

IBRION = 5 ! -1: Fix atoms; 0: MD; 2: ConjGrad relax; 44: improved dimer method

NSW = 1 ! Number electronic steps

ISIF = 0 # relax ions, no change cell shape, no change cell volume (volume changes require ENCUT*1.3)

POTIM = 0.015

parallel:

LPLANE = .TRUE.

# NPAR = 4