[Pw_forum] eigenvalue ordering in bands structure calculation

[zx3 at rice.edu]

Dear all:
    During calculating band structure of a zigzag band structure which has
partial flat band at the fermi level, I found that at some k points, the
eigenvalues written by bands.x are not ordered from lower to higher, it
introduces problems when I plot using gnuplot.
    I can modify band_plot.f90 to reorder this, but I wonder where is the origin
of this problem, and whether it will give wrong results in further process,
such as transport calculation. Thanks.

some of the parameters are:
 &system
    nspin = 1,
    ecutwfc = 30.0,
    ecutrho = 240.0
    occupations='smearing',
    smearing='gaussian',
    degauss=0.03,
    nbnd = 50,
 /
 &electrons
    conv_thr = 1.0e-10,
    mixing_beta = 0.3,
    diagonalization = 'cg',
 /

the full input file can be found at
http://www.ruf.rice.edu/~zx3/ribbon.nscf

Best,
Zhiping