vasp is not doing anythin....

Message

kanhere · #1 Post by **kanhere** » Fri Mar 16, 2007 8:23 am

i am trying to do a vasp calculation with the INCAR as:

ISTART = 0

NBANDS = 14

EDIFF = 0.001
EDIFFG = -0.01

IBRION = 2
NSW = 30
POTIM = 0.7

PREC = high
ISMEAR = -1
SIGMA = 0.02

ISPIN = 2
NUPDOWN = 14
VOSKOWN = 1

IALGO = 48
LDIAG = .TRUE.
NELM = 40
NELMIN = 4
NELMDL = -5

IMIX = 4
AMIX = 0.2
BMIX = 0.0001
#--------------- save memory--------------
ISYM = 0
LCHARG = .FALSE.
LELF = .FALSE.
LWAVE = .TRUE.
#---------------------------------------

but its not doing anything, i.e. getting stuck just after entering the main loop!!
vasp.4.6.21 13Feb03 gamma-only
POSCAR found : 2 types and 3 ions
WARNING: for PREC=h ENMAX is automatically increase by 25 %
this was not the case for versions prior to vasp.4.4
WARNING: for PREC=h ENMAX is automatically increase by 25 %
this was not the case for versions prior to vasp.4.4
LDA part: xc-table for Ceperly-Alder, Vosko type interpolation para-ferro
POSCAR, INCAR and KPOINTS ok, starting setup
FFT: planning ... 1
reading WAVECAR
entering main loop
N E dE d eps ncg rms rms(c)

and then doing nothin for 30 min(highest time i waited)....can anyone tell me the possible problem?

angie · #2 Post by **angie** » Fri Mar 16, 2007 4:15 pm

Well, I'm not an expert but, what system are you trying to calculate? how many atoms? how many k points? why are you using such a small SIGMA? and anyway, 30 minutes it's not a long time.

#3 Post by **admin** » Thu Mar 22, 2007 12:53 pm

first of all : ISYM=0 does not save memory.
please chek if your machine has enough memory for the box size you choose (the number of atoms itself is very small) or if it starts to swap.
please also check if all required libraries are installed correctly.

mukul · #4 Post by **mukul** » Thu Mar 29, 2007 12:31 am

This is the problem with NBANDS in your setting. As you are specifing NUPDOWN = 14 (i.e. spin = 14). In this case, NBANDS = 14 in not enough. Specify NBANDS = (# of electrons in the system + NUPDOWN)/2 + 4 ..... I BET YOUR PROBLEM WILL BE SOLVED.

your program is stuck because, you did not specity enough electronic levels.

#5 Post by **admin** » Thu Mar 29, 2007 9:28 am

if the number of bands is too small, VASP prompts an error
ERROR: Number of bands NBANDS too small to hold electrons
NELEC, NBANDS
and stops, but does not simply hang up