
This example illustrates how to use pw.x and postprocessing codes
- to make a contour plot in the [110] plane of the charge density for Si
- to plot the band structure of Si

The calculation proceeds as follows (for the meaning of the cited input
variables see the appropriate INPUT_* file)

1) make a self-consistent calculation (input=si.scf.in,
   output=si.scf.out)

2) run the postprocessing program pp.x (input=si.pp_rho.in, 
   output=si.pp_rho.out) in order to extract a 2D cut of 
   the charge density. See INPUT_PP for details of the input.

3) run plotrho.x program (input=si.plotrho.in, output=si.plotrho.out)
   in order to produce a postscript file: si.rho.ps.

4) make a non self-consistent calculation including more bands (nbnd=8). 
   (input=si.band.in, output=si.band.out) 

5) run program bands.x that extracts the eigenvalues, tries to 
   determine the correct crossing (based on the character of the 
   bands), writes bands to a file (sibands.dat). 
   (input=si.bands.in, output=si.bands.out) 

6) run program plotband.x that reads the file produced by bands.x
   and produces a postscript plot file (sibands.ps)
