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TABLE OF CONTENTS
   
   
   INTRODUCTION &lr_input 
prefix | outdir | restart | restart_step | lr_verbosity | disk_io
 &lr_control 
approximation | q1 | q2 | q3 | calculator | itermax | pseudo_hermitian | alpha_mix(i) | epsil | units | start | end | increment
 
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
  ...
/
&lr_control
  ...
/
   
 
|  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 must 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.
         
 |  
| restart | LOGICAL |  
| Default: | .false. |  | 
When set to .true., turbo_eels.x will attempt to restart
from a previous interrupted calculation. (see restart_step
variable).
Beware, if set to .false. turbo_eels.x will OVERWRITE any
previous runs.
         
 |  
| restart_step | INTEGER |  
| Default: | itermax |  | 
The code writes restart files every restart_step iterations.
Restart files are automatically written at the end of
itermax Lanczos steps.
         
 |  
| lr_verbosity | INTEGER |  
| Default: | 1 |  | 
This integer variable controls the amount of information
written to standard output.
         
 |  
| disk_io | CHARACTER |  
| Default: | 'default' |  | 
    Fine control of disk usage. Currently only 'reduced' is
supported where no restart files are written, apart from
the 'default' mode.
         
 |  | 
 |  
|  Namelist: &lr_control
 | 
|---|
 | | 
| approximation | CHARACTER |  
| Default: | 'TDDFT' |  | 
 A string describing a level of theory:
            
'TDDFT' :
Time-Dependent Local Density Approximation or
Time-Dependent Generalized Gradient Approximation
(depending on the XC functional)
             
'IPA' :
Independent Particle Approximation (IPA)
             
'RPA_with_CLFE' :
Random Phase Approximation (RPA) with
Crystal Local Field Effects (CLFE)
             |  
| q1, q2, q3 | REAL |  
| Default: | 1.0, 1.0, 1.0 |  | 
The values of the transferred momentum q = (q1, q2, q3)
in Cartesian coordinates in units of 2pi/a, where
"a" is the lattice parameter.
         
 |  
| calculator | CHARACTER |  
| Default: | 'lanczos' |  | 
Variable that controls which algorithm is used to compute EELS spectra.
            
'lanczos' :
corresponds to the Lanczos recursive algorithm
             
'sternheimer' :
corresponds to the Sternheimer algorithm
             |  
| itermax | INTEGER |  
| Default: | 500 |  | 
When calculator = 'lanczos', itermax is the
maximum number of Lanczos iterations that will be performed.
When calculator = 'sternheimer', itermax is the
maximum number of iterations in a SCF step for each frequency.
         
 |  
| pseudo_hermitian | LOGICAL |  
| Default: | .true. |  | 
This variable is used only when calculator = 'lanczos'.
When set to .true. the pseudo-Hermitian Lanczos algorithm is
used. When set to .false. the non-Hermitian Lanczos
biorthogonalization algorithm is used (which is two times slower).
         
 |  
| alpha_mix(i) | REAL |  
| Default: | alpha_mix(1)=0.7 |  | 
This variable is used only when calculator = 'sternheimer'.
Mixing parameter (for the i-th iteration) for updating
the response SCF potential using the modified Broyden
method: D.D. Johnson, PRB 38, 12807 (1988).
         
 |  
| epsil | REAL |  
| Default: | 0.02 |  | 
This variable is used only when calculator = 'sternheimer'.
The broadening/damping term (in Rydberg units).
         
 |  
| units | INTEGER |  
| Default: | 0 |  | 
This variable is used only when calculator = 'sternheimer'.
The unit system used for the output, for start, end,
and increment input parameters.
0 = Rydbergs, 1 = Electron volts.
         
 |  
| start | REAL |  
| Default: | 0.0 |  
| See: | end, increment |  | 
This variable is used only when calculator = 'sternheimer'.
start is the value of frequency starting from which the
susceptibility and the loss function (-Im(1/eps)) will be computed.
start is specified in units controlled by units.
         
 |  
| end | REAL |  
| Default: | 2.5 |  
| See: | start, increment |  | 
This variable is used only when calculator = 'sternheimer'.
end is the value of frequency up to which the
susceptibility and the loss function (-Im(1/eps)) will be computed.
end is specified in units controlled by units.
         
 |  
| increment | REAL |  
| Default: | 0.001 |  
| See: | start, end |  | 
This variable is used only when calculator = 'sternheimer'.
increment is an incremental step used to define the mesh
of frequencies between start and end.
increment is specified in units controlled by units.
         
 |  | 
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