WARNING: Sub-Space-Matrix is not hermitian in DAV            4
 5.466653149832755E-004
WARNING: Sub-Space-Matrix is not hermitian in DAV            5
 6.390243522781398E-004
WARNING: Sub-Space-Matrix is not hermitian in DAV            4
 5.466653149832755E-004
WARNING: Sub-Space-Matrix is not hermitian in DAV            5
 6.390243522781398E-004
WARNING: Sub-Space-Matrix is not hermitian in DAV            6

计算过程中遇到这个问题，怎么解决呢？

VASP FORUM:
the error is due to a LAPCK call (ZHEGV):
ZHEGV computes all the eigenvalues, and optionally, the eigenvectors
of a complex generalized Hermitian-definite eigenproblem .
there may be several reasons for that error:
1) the RMM-DIIS diagonalisation algorithm is not stable for your specific
setup of the calculation.
--> use ALGO = Normal (blocked Davidson) or
ALGO = Fast (5 steps blocked Davidson, RMM-DIIS)
2)
a) maybe your input geometry was not reasonable (error occurs at the very first ionic
step, please have a look for the geometry data of your run in OUTCAR ) or
b) the last ionic relaxation step lead to an unreasonable geometry (compare the input
and output geometries of the last ionic relaxation steps in XDATCAR).
In that case (2b) it can be helpful to
--> switch to a different relaxation algorithm (IBRION-tag)
--> reduce the step size of the first step by setting POTIM smaller than the default
value
3) The installation of the LAPACK on your machine was not done properly:
use the LAPACK which is delivered with the code
(vasp.4.lib/lapack_double.o)
4) If the error persist although you switched to the Davidson algorithm:
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.

注： 我是在静态计算中遇到这样的问题，通过改变POTIM 从0.5 变成 0.1 问题就解决了。