My Community

Hello,

I run the serial version of VASP 4.6.28 on an itanium based HP-UX
system. I start with a clean input (only INCAR, KPOINTS, POSCAR and
POTCAR). In the middle of the electronic relaxation, I get this message:
Why is there suddenly a problem with the charge density?
Or is this a mathematical inaccuracy?
(I'm using HP-UX lapack and veclib libraries).

Can someone help me understand what is the problem here?

Input and output files are here:

http://surfion.snu.ac.kr/~lahaye/vasp

Thank you,
Rob.

1) please have a look whether the grid for the Broyden mixing is lage enough
(WARNING: grid for Broyden might be to small in OUTCAR). If so, increase PREC and check if the error persists
2) in case you use a tetrahedron method for BZ integration your k-mesh should be large enough to fill the (I)BZ with tetrahedra completely

I'm using Monkhorst-Pack for the K-point sampling.

But yes indeed, I have this broyden warning in my OUTCAR file:
However, my PREC setting is already "High".
This should be highest setting, right?
Also, this problem seems to occur on my HP-UX system
only; similar calculation on Linux system goes fine.

Is there something known about HP-UX related issues?

Thanks,
Rob.

PS: typo in the WARNING message: s/to/too/

Hi ,
I upgraded vasp version from 4.6.27 to 4.6.31 and compiled it with ifc 9.1. With the new executables, I had the same problem on an SGI itanium machine with intel compilers,
BRMIX, old and new charge density problem. So it seemed to me that something was wrong with the compilation because with the same inputs, I did the calculations on different arthitectures without any problem.. So I decreased the intel fortran compiler version level to 9.0.
Now everthing seems to be fine. No BRMIX problem.
NB: I only had this problem on SGI Itanium. On Linux EM64t machines withifc 9.1 , I have no problem.
Mustafa

Hi, all
I have the same problem with vasp serial version 4.6.31 compiled with IBM xlf90 10.1.0.5 compiler.
The error occurs already by running benchmark test supplied with VASP.
On other machines there was no this error

The problem disappears after reducing optimization level from -O4 to -O3.

I am having the same problem on Linux EM64T machine. I am using intel fortran compiler 10.1.008. It works with serial version just fine, but the parallel version only works if I reduce optimization flag to -01 at which point the serial version is faster anyways.

[quote="admin"]1) please have a look whether the grid for the Broyden mixing is lage enough
(WARNING: grid for Broyden might be to small in OUTCAR). If so, increase PREC and check if the error persists
2) in case you use a tetrahedron method for BZ integration your k-mesh should be large enough to fill the (I)BZ with tetrahedra completely[/quote]

Increase KPOINT mesh and it helped.

Add the item "ADDGRID = TRUE"

Set ISYM = 0 explicitly in the INCAR file. (I had ADDGRID added as well). Helped me with VASP 4.6 and VASP 5.2.2

I have run into this problem before and just hit it again. I know this thread is a little old, but for me it is the top google result when searching the error, so it is maybe useful to contribute.

I most recently ran into this running simple bulk Al in a 3x3x3 supercell. It happened at a variety of kmeshes, and didn't happen at all when I was using basically the same settings on a 4x4x4 supercell.

Like albertg, I found that decreasing the symmetry solved the problem, but I found that it was sufficient to merely offset one of my atoms' initial position just a little bit. This is I think less expensive than turning off symmetry, so hopefully it is helpful to you.

I'm still not sure what caused the problem to start with...bulk Al is basically as simple as it gets :p

Cheers

Same issue here, set ISYM=0 do solve the problem