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 Message of " Sub-Space-Matrix is not hermitian "

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TING QIN
Tue May 23 2006, 12:59PM Quote
Registered Member #523
Joined Tue Jan 10 2006, 11:13AM
posts 5
Hi, I do calculations for transition metals with respect to primitive monoclinic structure containing 16 atoms. VASP runs in the cluster and uses 4 processors. The INCAR is listed below:
SYSTEM = A12
ENCUT = 330
EDIFF=0.000001
ISMEAR =1
SIGMA = 0.1
IBRION=2
ISIF=3
NSW=1000
EDIFFG = -0.01
AMIX = 0.02

During the electronic structure relaxation, it always display lots of warning messages “WARNING: Sub-Space-Matrix is not hermitian in DAV 4” and eventually the calculation fails with such error message “Error EDDDAV: Call to ZHEGV failed. Returncode = 47 315”

As seen, I set AMIX from the default value of 0.4 to 0.02, and the problem still exists.
What is the reason and how can I avoid such problem?
Many thanks.
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admin
Tue May 23 2006, 01:45PM Quote

posts 2520
there may be several reasons for this error, the most common are
1a) the input geometry was not reasonable (error occurs at the very first ionic step) or
1b) the last ionic relaxation step lead to an unreasonable geometry (compare the input and output geometries of the
last ionic relaxation steps). In that case it can be helpful to
--> switch to a different relaxation algorithm (IBRION-tag)
--> reduce the step size of the first step by setting POTIM explicitely
2) If this error shows up at all your calculations: The installation of the LAPACK on your machine was not done properly: use a different LAPACK, e.g. the LAPACK which is delivered with the code
(vasp.4.lib/lapack_double.o)
3) on some architectures (especially SGI) some Lapack
routines are not working properly. However, it is
possible to avoid the usage of the ZHEGV subroutine
by commenting the line #define USE_ZHEEVX in
davidson.F, subrot.F, and wavpre_noio.F and recompiling
VASP.
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sridevi
Tue May 30 2006, 02:47PM Quote
Registered Member #544
Joined: Tue Jan 24 2006, 03:13PM
posts 5
I got the same problem.
If you are using vasp 4.6. Try using "IALGO =48" in the INCAR file.
It solved the problem for me.

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jcconesa
Sun Jan 07 2007, 06:06PM Quote
Registered Member #760
Joined: Mon Jul 03 2006, 10:48AM
Location: Madrid
posts 17
Hi,
I got the same problem on a sgi machine when running the Cu benchmark. Changing to IALGO=48 just changed the problem; then I get the messages:
.............
lib-4201: UNRECOVERABLE library error.

Encountered during a direct access unformatted READ from unit 21.
Fortran unit 21 is connected to a direct unformatted unblocked file: "TMPCAR"
IOT trap

core dumped
.....................

These messages appeared after 20 cycles of RMM: and one line beginnig with
1 T= 2080. E= -.90209009E+04 E0=...

Please help to solve. Concerning previous admin comments I should say that in the davidson, subrot and wavpre_noio files the variable "USE_ZHEEVX" does not control whether ZHEGV is used or not; this seems to depend rather on the definition of the variable "gammareal".
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admin
Wed Jan 24 2007, 02:05PM Quote

posts 2520
1) if you set USE_ZHEEVX
DSYEVX instead of DSYEV is used if gamma_real
ZHEEVX ZHEEV all other cases.
so it does not only affect the gamma-real version.


2) please have a look to the FAQs of the manual:
(http://cms.mpi.univie.ac.at/vasp/vasp/node265.html,
"I am running VASP on a SGI Origin, and the ...)
set IWAVPR=10
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jcconesa
Mon Feb 19 2007, 05:27PM Quote
Registered Member #760
Joined: Mon Jul 03 2006, 10:48AM
Location: Madrid
posts 17
Hi,
I continue to have the previously reported problem found when trying to run the Cu benchmark on a sgi machine, i.e. the program aborts and the output ends with a series of lines such as

entering main loop
N E dE d eps ncg rms
rms(c)
WARNING: Sub-Space-Matrix is not hermitian in DAV 1, -18.497193968206293
WARNING: Sub-Space-Matrix is not hermitian in DAV 2, -106.6910638174717
WARNING: Sub-Space-Matrix is not hermitian in DAV 3, -3.4046873909742339
WARNING: Sub-Space-Matrix is not hermitian in DAV 4, -37.403094929979197
WARNING: Sub-Space-Matrix is not hermitian in DAV 5, 0.14502948098981785

followed by

Error EDDDAV: Call to ZHEGV failed. Returncode = 13 1 8

The earlier solution suggested by admin (suppressing the line #define USE_ZHEEVX in davidson.F, subrot.F, and wavpre_noio.F and recompiling VASP) does not work, i.e. the same error messages, and the same indication of ZHEGV failure, still appear. I may add now that the problem appears both with the lapack which comes with VASP and with a system-native lapack library.

The warnings given suggest that the problem actually appears at an earlier stage, in which a matrix is generated with inadequate values which make it nonhermitian, and consequently ZHEGV fails even if working correctly; the solution thus would not be to avoid using ZHEGV, but to avoid an incorrect generation of the said matrix.

Can someone give an idea to really solve the problem?
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konglt
Tue Feb 20 2007, 03:01PM Quote
Registered Member #248
Joined: Wed Jun 15 2005, 09:57AM
Location: Montreal
posts 35
Please try if it works by adding "LSCALAPACK = .FALSE." in your INCAR.
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konglt
Tue Feb 20 2007, 03:03PM Quote
Registered Member #248
Joined: Wed Jun 15 2005, 09:57AM
Location: Montreal
posts 35
Please try if it works by adding "LSCALAPACK = .FALSE." in your INCAR.
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jcconesa
Tue Feb 20 2007, 11:04PM Quote
Registered Member #760
Joined: Mon Jul 03 2006, 10:48AM
Location: Madrid
posts 17
No; adding "LSCALAPACK = .FALSE." in INCAR makes no dfference, the problem continues the same.
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ntq1982
Sat Feb 21 2009, 06:11AM Quote
Registered Member #2102
Joined: Thu Feb 28 2008, 12:30AM
Location: Japan
posts 1
I was successful to fix this problem by using IALGO=48 instead of IALGO=Default
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xiaomatao
Fri Mar 06 2009, 09:15AM Quote
Registered Member #917
Joined: Fri Oct 13 2006, 12:04PM
posts 4
unfortunately, when i set IALGO=48, the new warning is
WARNING in EDDRMM: call to ZHEGV failed, returncode = 6 314
how to solve this problem?
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