ABINIT Discussion Forums

Hello,
i wana to calculate polarization of bifeo3 by lda+u,but i have WARNING that i can't undrestand it,could you please explain it for me?
i have sent my input file and my WARNING.
input:
acell 5.58132 5.58132 13.87698
angdeg 90 90 120
spgroup 161
brvltt -1
chkprim 0
#Atom definition
natom 10
natrd 3
ntypat 3
znucl 83 26 8
typat 1 1 2 2 3 3 3 3 3 3

#SCF parameters
ixc 7
iscf 17
nstep 100
#planewave basis
ecut 90
pawecutdg 100
pawovlp -1.6
kptopt 4
ngkpt 2 2 2
nshiftk 1
shiftk 0.5 0.5 0.5
toldfe 1.0d-12
#Berry phase calculation of the polarization

berryopt -1
rfdir 1 1 1
xred 0.000000000 0.000000000 0.000000000
0.000000000 0.000000000 0.221200004
0.442999989 0.012000000 0.954299986
nbdbuf 0
usepawu 1
lpawu -1 2 -1
upawu 0.0 7.0 0.0
jpawu 0.0 0.9 0.0
WARNING:
mkdenpos : WARNING -
Density went < 0 at 24 points
and was set to 1.00E-14. Lowest was -0.65E-01.
Likely due to too low boxcut or too low ecut for pseudopotential core charge.
Thank you.

Maybe the problem is that your paw U and J are very large--note that these default to atomic units, so an input of 7.0 means 7.0 Hartree, you probably wanted 7.0 eV here, so you should be using 7.0/27.2 = 0.257; likewise for J.