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BRMIX: very serious problems the old and the new charge density differ old charge density

Posted: Thu Sep 02, 2010 8:36 pm
by cajuan@criba.edu.ar
Running one Fe (110) surface we get this error message in the STDOUT:

BRMIX: very serious problems
the old and the new charge density differ
old charge density: 192.00000 new 186.62159
0.558E+01

reading the outcar no error is printed

somebody could help me?

BRMIX: very serious problems the old and the new charge density differ old charge density

Posted: Sun Sep 05, 2010 2:40 am
by cpp6f
This is one of the symptoms of the "incorrect number of electrons" problem I just posted about. Are you using the intel compiler? That is the only compiler I have trouble with. Is the number of electrons printed in the outcar for the first scf step even correct? For me it is not.

BRMIX: very serious problems the old and the new charge density differ old charge density

Posted: Sun Sep 26, 2010 1:11 pm
by admin
please make sure that you did not set NELEC in INCAR.
please also provide some more details of the run that produced the error. At which point of the run did this error show up? Did you choose NBANDS sufficiently high? Maybe it helps to decrease the charge and spin density mixing parameters.

BRMIX: very serious problems the old and the new charge density differ old charge density

Posted: Tue Nov 02, 2010 4:42 pm
by ucapcrw
I get the same error when running a graphite intercalate calcuation (KC14).

The system is 14 C atoms and 1 K atom in a hexagonal unit cell. SYMPREC=1E-06, a plane wave cut off of 500eV and EDIFFG=-1E-07.

For my KPOINTS I use:

Code: Select all

Automatic
0
Gamma
7.  7.  7.
0.  0.  0.
And get the error in the stdout:

Code: Select all

BRMIX: very serious problems
 the old and the new charge density differ
 old charge density:    63.00066 new   62.99998
And in OUTCAR I get on the very last line:

Code: Select all

----------------------------------------- Iteration    1(  34)  ---------------------------------------


    POTLOK:  VPU time    0.00: CPU time    0.02
    SETDIJ:  VPU time    0.00: CPU time    0.01
Error EDDDAV: Call to ZHEGV failed. Returncode = 145 5 2
If I run the same calculation with a KPoint grid of 6x6x6 or 8x8x8 or 5x5x5 it's fine, but not for 7x7x7. Is this anything I should worry about?

Thank you in advance,
Charlie

BRMIX: very serious problems the old and the new charge density differ old charge density

Posted: Wed Nov 03, 2010 8:06 am
by alex
Hexagonal cell? Try Gamma instead of Monkhorts scheme in KPOINTS. Should work best for all k-point sets.

Cheers,

alex