[Wien] density matrix is not positive

[Llin Layton]

Dear wien2k users,
I am working on Nd4Ni3O10 with the latest wien2k 19.1, during my LDA+U
calculations. However, I constantly encountered warning messages:
WARNING: Density Matrix is not positive semi-definite
WARNING: Density Matrix has -ve terms
and it takes about 200 iterations to reach the default converge conditions.
I set the Ueff=8eV for 4f electrons of Nd and Ueff=6eV for Ni's 3d
electrons, rkmax=7.5 with 1200 kpoints, rmt is set by setrmt. Besides, I
find the 4f orbital is always localized at fermi energy, which is also the
case for Nd4Ni3O8, and I have performed normal LDA calculations before +U.
So, my questions are:
1. Is this a serious warning or I can just ignore it since it can still
converge?
2. Is that normal to find the 4f orbital localized at the fermi energy
given that I have set Ueff=8eV for it?
Any suggestions will be appreciated.

Yours sincerely,

Fan
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