CG scaled line search
Posted: Wed Sep 02, 2009 6:20 pm
I'm having trouble getting VASP to do a simple configuration relaxation calculation.
I've been running VASP for a couple of years now and we've recently updated our cluster and I'm getting a strange output from the code that I've never gotten before:
CG: scaled line search X= 0.0000 F= -23.0335 dX= 1.0000
CG: unscaled line search X= 0.0000 F= -21.8506 dX= 1.0541
The problem is as follows: I'm trying to do a simple relaxation calculation to figure out the ground state configuration and energy of a system, however, instead of going through the many ionic and electronic relaxations it stops after the first ionic step. It's doing this for many configurations and so I know it has nothing to do with that.
Below is my INCAR:
Electronic minimization
PREC = NORM
GGA = 91
VOSKOWN = 1
IALGO = 48
ISYM = 0
ISPIN = 2
LREAL = Auto
NELM = 300
EDIFF = 1E-4
Ionic relaxation
EDIFFG = 1E-3
NSW = 100
IBRION = 2
POTIM = 0.5
DOS related values
ISMEAR = 2 ; SIGMA=0.2
NPAR = 1
Energy values for adsorption comparison
ENMAX = 395.994
RWIGS = 0.5
My output is as below, note it stops at the first ionic step:
N E dE d eps ncg rms rms(c)
RMM: 1 0.631782272979E+01 0.63178E+01 -0.13524E+01 10 0.232E+01
.......................
.......................
.......................
RMM: 25 -0.111316798268E+01 -0.11573E-03 0.00000E+00 18 0.000E+00 0.267E-04
RMM: 26 -0.111323473291E+01 -0.66750E-04 0.00000E+00 18 0.000E+00
1 F= -.11132347E+01 E0= -.11146113E+01 d E =-.111323E+01 mag= 1.0000
trial: gam= 0.00000 g(F)= 0.000E+00 g(S)= 0.000E+00 ort = NaN (trialstep = 0.100E+01)
search vector abs. value= 0.000E+00
CG: scaled line search X= 0.0000 F= 0.0000 dX= 1.0000
CG: unscaled line search X= 0.0000 F= NaN dX= 0.0000
reached required accuracy - stopping structural energy minimisation
writing wavefunctions
I've never seen these last couple of lines that state "CG: scaled...." and "CG: unscaled....". I suspect this has something to do with why the code is prematurely terminating. Can anyone tell me what these CG flags mean? Can anyone help me get back to a simple relaxation?
Thanks!
Regards,
mff7d
I've been running VASP for a couple of years now and we've recently updated our cluster and I'm getting a strange output from the code that I've never gotten before:
CG: scaled line search X= 0.0000 F= -23.0335 dX= 1.0000
CG: unscaled line search X= 0.0000 F= -21.8506 dX= 1.0541
The problem is as follows: I'm trying to do a simple relaxation calculation to figure out the ground state configuration and energy of a system, however, instead of going through the many ionic and electronic relaxations it stops after the first ionic step. It's doing this for many configurations and so I know it has nothing to do with that.
Below is my INCAR:
Electronic minimization
PREC = NORM
GGA = 91
VOSKOWN = 1
IALGO = 48
ISYM = 0
ISPIN = 2
LREAL = Auto
NELM = 300
EDIFF = 1E-4
Ionic relaxation
EDIFFG = 1E-3
NSW = 100
IBRION = 2
POTIM = 0.5
DOS related values
ISMEAR = 2 ; SIGMA=0.2
NPAR = 1
Energy values for adsorption comparison
ENMAX = 395.994
RWIGS = 0.5
My output is as below, note it stops at the first ionic step:
N E dE d eps ncg rms rms(c)
RMM: 1 0.631782272979E+01 0.63178E+01 -0.13524E+01 10 0.232E+01
.......................
.......................
.......................
RMM: 25 -0.111316798268E+01 -0.11573E-03 0.00000E+00 18 0.000E+00 0.267E-04
RMM: 26 -0.111323473291E+01 -0.66750E-04 0.00000E+00 18 0.000E+00
1 F= -.11132347E+01 E0= -.11146113E+01 d E =-.111323E+01 mag= 1.0000
trial: gam= 0.00000 g(F)= 0.000E+00 g(S)= 0.000E+00 ort = NaN (trialstep = 0.100E+01)
search vector abs. value= 0.000E+00
CG: scaled line search X= 0.0000 F= 0.0000 dX= 1.0000
CG: unscaled line search X= 0.0000 F= NaN dX= 0.0000
reached required accuracy - stopping structural energy minimisation
writing wavefunctions
I've never seen these last couple of lines that state "CG: scaled...." and "CG: unscaled....". I suspect this has something to do with why the code is prematurely terminating. Can anyone tell me what these CG flags mean? Can anyone help me get back to a simple relaxation?
Thanks!
Regards,
mff7d