------------------------------------------------------------------------
INPUT FILE DESCRIPTION

Program: bands.x / PWscf / Quantum Espresso
------------------------------------------------------------------------


Purpose of bands.x:
    Rewrite the bands ordering them using the overlap
    of the wave-functions on neighbor k points
    and calculate properties of each eigen-function.

Presently it can calculate:

   (a) The expectation value of the spin operator on each spinor
       wave-function.
   (b) The symmetry properties of each wavefunction. With this option
       the bands are not ordered according to the overlap.

The input data of this program are read from standard input
or from a file and have the following format:


Structure of the input data:
============================

   &BANDS
     ...
   /



========================================================================
NAMELIST: &BANDS

   +--------------------------------------------------------------------
   Variable:       prefix
   
   Type:           CHARACTER
   Description:    prefix of files saved by program pw.x
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       outdir
   
   Type:           CHARACTER
   Description:    temporary directory where pw.x files resides
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       filband
   
   Type:           CHARACTER
   Description:    file "filband" contains the bands
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       spin_component
   
   Type:           INTEGER
   Description:    In the lsda case select:
                   
                      1 = spin-up
                      2 = spin-down
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       lsigma(i), i=1,3
   
   Type:           LOGICAL
   Description:    If true writes a file filband.i with the expectation
                   values of the spin operator on the spinor wave-functions.
                   (only in the noncollinear case).
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       lsym
   
   Type:           LOGICAL
   Description:    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.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       no_overlap
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. writes the eigenvalues in the output file
                   without changing their order.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       plot_2d
   
   Type:           LOGICAL
   Default:        .false.
   Description:    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
                   ..  ..  ..
                   enegies are written in eV and xk in units 2\pi/a.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variables:      firstk, lastk
   
   Type:           INTEGER
   Description:    if lsym=.true. makes the symmetry analysis only for k
                   points between firstk to lastk
   +--------------------------------------------------------------------
   
===END OF NAMELIST======================================================