[Wannier] ERROR: unitarity of initial U

[Gianluca Giovannetti]

Dear All,

i`m working on extracting the Wannier functions of LiV2O4.
The trigonal symmetry splits the low-lying t_{2g} levels into one a_{1g}
and two degenerate e_{g}^pi levels, with the former slightly lower in
energy and narrower in bandwidth. The density of states looks very simple.
At Fermi level there are Vanadium d bands having a bandwidth of ~ 2eV.
Below in energy separated from the Vanadium d bands there are bands with
predominant Oxygen p bands.
I can extract with no problem the Vanadium d bands using an energy window
sitting at the Vanadium d bands.
Wannier90 bands are on top of DFT bands (i also compared mine with some
known in literature).
As a starting point for the projection i used:

begin projections
V:dxz;dyz;dxy
end projections
Once i try to calculate Wannierfunctions for "d" and "p" orbitals i get the
following error:

   A_mn = <psi_m|g_n> --> S = A.A^+ --> U = S^-1/2.A
   In dis_project...  ERROR: unitarity of initial U
 nkp=  1
 i=  2  j=  4
 [u_matrix_opt.transpose(u_matrix_opt)]_ij=     0.114936    -0.050292
 Exiting.......
 dis_project: Error in unitarity of initial U in dis_project

Do you have any idea for solving it?
Below it is my input file.

thank you in advance.

Gianluca Giovannetti

=========================

iprint = 3
num_bands       = 70
num_wann        = 36

num_iter        =  2000
num_print_cycles = 100

dis_win_max     = 9.1
dis_win_min     = -0.5

dis_num_iter    = 200
dis_mix_ratio   = 0.75

write_r2mn=.true.
hr_plot=.true.

kmesh_tol=0.00001

! SYSTEM

begin unit_cell_cart
bohr
7.789167066 0.0000 7.789167066
0.0000 7.789167066 7.789167066
7.789167066 7.789167066 0.0000
end unit_cell_cart

begin atoms_cart
Ang
V    0.000000    0.000000    0.000000
V    2.060925    2.060925    0.000000
V    2.060925    0.000000    2.060925
V    0.000000    2.060925    2.060925
O     0.094555000   0.094555000  1.966370000
O     1.966370000   1.966370000  1.966370000
O     0.094555000   1.966370000  0.094555000
O     1.966370000   0.094555000  0.094555000
O    -0.094556000   4.027295000  2.155480000
O     2.155480000  -1.966370000  2.155480000
O    -0.094556000  -1.966370000 -0.094556000
O     2.155480000   4.027295000 -0.094556000
Li     1.030463000   5.152312000  1.030463000
Li     3.091388000   3.091388000  3.091388000
end atoms_cart

begin projections
V:dxz;dyz;dxy
O:px;py;pz
end projections

begin kpoint_path
G 0.00  0.00  0.00    X 0.00  0.50  0.50
X 0.00  0.50  0.50    W 0.25  0.75  0.50
W 0.25  0.75  0.50    L 0.00  0.50  0.00
L 0.00  0.50  0.00    G 0.00  0.00  0.00
end kpoint_path
bands_plot = .true.

!To plot the WF
!wannier_plot = T
!wannier_plot_supercell = 2
!wannier_plot_list = 1-12
!restart = plot

! KPOINTS

mp_grid : 8 8 8

begin kpoints
.............
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/wannier/attachments/20121102/1e5d7250/attachment.html>