TABLE OF CONTENTS
INTRODUCTION
&LR_INPUT
prefix  outdir  verbosity  itermax0  itermax  extrapolation  epsil  units  start  end  increment  ipol  eels  magnons  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
 'no' :
no extrapolation.

epsil 
REAL 
Default: 
0.02

The broadening/damping term. In Rydberg units if magnons=.false.,
in meV if magnons = .true.

units 
INTEGER 
Default: 
0

The unit system used for the output and the start, end and increment
input parameters. (only meV used in that case).
0 = Rydbergs, 1 = Electron volts, 2 = Nanometres per electron volts,
3 = milli Electron volts (only for magnons=.true.)

start 
REAL 
Default: 
0.0

The polarizability and the absorption coefficient are computed
starting from this value. In units set.

end 
REAL 
Default: 
2.5

The polarizability and the absorption coefficient are computed
up to this value. In units set.

increment 
REAL 
Default: 
0.001

Incremental step used to define the mesh between start and end.
In units set.

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. EELSspecific operations
will be performed.

magnons 
LOGICAL 
Default: 
.false.

Must be set to .true. for magnoncalculation postprocessing.

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.



