TABLE OF CONTENTS
INTRODUCTION
&BANDS
prefix  outdir  filband  spin_component  lsigma  lp  filp  lsym  no_overlap  plot_2d  firstk  lastk
INTRODUCTION
Purpose of bands.x:
Reorder bands, computes bandrelated properties. Currently,
reordering can be done with two different algorithms:
(a) by maximising the overlap with bands at previous kpoint
(b) by computing symmetry properties of each wavefunction
Bandsrelated properties that can be computed are currently
(a) The expectation value of the spin operator on each spinor
wavefunction (noncolinear case only)
(b) The expectation value of p
The input data can be read from standard input or from file using
commandline options "bands.x i filename" (same syntax as for pw.x)
Output files:
 file filband containing the band structure, in a format
suitable for plotting code "plotband.x"
 file "filband".rap (if lsym is .t.) with symmetry information,
to be read by plotting code "plotband.x"
 if (lsigma(i)): file "filband".i, i=1,2,3, with expectation values
of the spin operator in the noncolinear case
 file "filband".gnu with bands in eV, directly plottable using gnuplot
 file filp with matrix elements of p (including the nonlocal potential
contribution i*m*[V_nl,x])
Structure of the input data:
============================
&BANDS
...
/
Namelist: &BANDS

prefix 
CHARACTER 
Default: 
'pwscf'

prefix of files saved by program pw.x

outdir 
CHARACTER 
Default: 
value of the ESPRESSO_TMPDIR environment variable if set;
current directory ('./') otherwise

directory containing the input data, i.e. the same as in pw.x

filband 
CHARACTER 
Default: 
'bands.out'

file name for band output (to be read by "plotband.x")

spin_component 
INTEGER 
In the lsda case select:
1 = spinup
2 = spindown

lsigma(i), i=1,3 
LOGICAL 
If true computes expectation values of the spin operator
on the spinor wavefunctions (only in the noncollinear case),
writes them to a file "filband".i, i=1,2,3

lp 
LOGICAL 
Default: 
.false.

If .true. matrix elements of the momentum operator p between
conduction and valence bands are computed and written to file
specified in filp.
The matrix elements include the contribution from the nonlocal
potential, i*m*[V_nl, x]. In other words, the calculated matrix elements
are those of the velocity operator i*m*[H, x] times mass, not those of
the true momentum operator.

filp 
CHARACTER 
Default: 
'p_avg.dat'

If lp is set to .true., file name for matrix elements of p

lsym 
LOGICAL 
Default: 
.true.

If .true. the bands are classified according to the
irreducible representations of the small group of k.
A file "filband".rap with the same format of "filband"
is written, for usage by "plotband.x"

no_overlap 
LOGICAL 
Default: 
.true.

If .false., and if lsym is .false., writes the eigenvalues
in the order that maximises overlap with the neighbor kpoints

plot_2d 
LOGICAL 
Default: 
.false.

If .true. writes the eigenvalues in the output file
in a 2D format readable by gnuplot. Band ordering is not
changed. Each band is written in a different file called
filband.# with the format:
xk, yk, energy
xk, yk, energy
.. .. ..
energies are written in eV and xk in units 2\pi/a.

firstk, lastk 
INTEGER 
if lsym=.true. makes the symmetry analysis only for k
points between firstk to lastk



