| 
TABLE OF CONTENTS
   
   
   INTRODUCTION &lr_input 
prefix | outdir | verbosity | itermax0 | itermax | extrapolation | epsil | units | start | end | increment | ipol | eels | td | eign_file
 
INTRODUCTION
    Input data format: { } = optional, [ ] = it depends.
All quantities whose dimensions are not explicitly specified are in
RYDBERG ATOMIC UNITS
BEWARE: TABS, DOS <CR><LF> CHARACTERS ARE POTENTIAL SOURCES OF TROUBLE
Comment lines in namelists can be introduced by a "!", exactly as in
fortran code. Comments lines in ``cards'' can be introduced by
either a "!" or a "#" character in the first position of a line.
Structure of the input data:
===============================================================================
&lr_input
  ...
/
   
 
|  Namelist: &lr_input
 | 
|---|
 | |  This namelist is always needed !
       
| prefix | CHARACTER |  
| Default: | 'pwscf' |  | 
Sets the prefix for generated and read files. The files
generated by the ground state pw.x run should have this
same prefix.
         
 |  
| outdir | CHARACTER |  
| Default: | './' |  | 
The directory that contains the run critical files, which
include the files generated by ground state pw.x run.
         
 |  
| verbosity | INTEGER |  
| Default: | 1 |  | 
This integer variable controls the amount of information
written to standard output.
         
 |  
| itermax0 | INTEGER |  
| Default: | 500 |  | 
Number of Lanczos coefficients to be read from the file.
         
 |  
| itermax | INTEGER |  
| Default: | 500 |  | 
The total number of Lanczos coefficients that will be
considered in the calculation of the polarizability/absorption
coefficient. If itermax > itermax0, the Lanczos coefficients
in between itermax0+1 and itermax will be extrapolated.
         
 |  
| extrapolation | CHARACTER |  
| Default: | 'no' |  | 
    Sets the extrapolation scheme. 'osc'= biconstant extrapolation,
'constant'=constant extrapolation and 'no'=no extrapolation.
         
 |  
| epsil | REAL |  
| Default: | 0.02 |  | 
The broadening/damping term (in Rydberg units).
         
 |  
| units | INTEGER |  
| Default: | 0 |  | 
    The unit system used for the output and the start, end and increment
input parameters.
0 = Rydbergs, 1 = Electron volts and 2 = Nanometres per electron volts.
         
 |  
| start | REAL |  
| Default: | 0.0 |  | 
  The polarizability and the absorption coefficient are computed
starting from this value. In units set by the units variable.
         
 |  
| end | REAL |  
| Default: | 2.5 |  | 
  The polarizability and the absorption coefficient are computed
up to this value. In units set by the units variable.
         
 |  
| increment | REAL |  
| Default: | 0.001 |  | 
  Incremental step used to define the mesh between start and end.
In units set by the units variable.
         
 |  
| ipol | INTEGER |  
| Default: | 1 |  | 
An integer variable that determines which element of the
dynamical polarizability will be computed:
1 -> alpha_xx(omega), 2 -> alpha_yy(omega), and
3 -> alpha_zz(omega). When set to 4, three Lanczos chains
are sequentially performed and the full polarizability
tensor and the absorption coefficient are computed.
         
 |  
| eels | LOGICAL |  
| Default: | .false. |  | 
Must be set to .true. for EELS. EELS-specific operations
will be performed.
         
 |  
| td | CHARACTER |  
| Default: | 'lanczos' |  | 
When set to 'lanczos', a calculation of the spectrum is
performed using the Lanczos coefficients.
When set to 'davidson' or 'david', a calculation of the
spectrum is performed using the eigenvalues computed
using the Davidson algorithm. See the variable 'eign_file'.
         
 |  
| eign_file | CHARACTER |  
| Default: | 'pwscf.eigen' |  | 
The name of the file produced by the turbo_davidson.x code,
in which are written the eigenvalues.
         
 |  | 
 |  |