Input File Description

Program: wfreq.x / West / Quantum Espresso

TABLE OF CONTENTS

INTRODUCTION

&WSTAT_CONTROL

wstat_calculation | n_pdep_eigen | n_pdep_times | n_pdep_maxiter | n_dfpt_maxiter | n_pdep_read_from_file | trev_pdep | trev_pdep_rel | tr2_dfpt | l_minimize_exx_if_active | l_kinetic_only | l_use_ecutrho

&WFREQ_CONTROL

wfreq_calculation | n_pdep_eigen_to_use | qp_bandrange | macropol_calculation | n_lanczos | n_imfreq | n_refreq | ecut_imfreq | ecut_refreq | wfreq_eta | n_secant_maxiter | trev_secant | l_enable_lanczos | o_restart_time | ecut_spectralf | n_spectralf

INTRODUCTION

Typical run:
===============================================================================

export MPI_TASKS=12
export NIMAGE=2

mpirun -n $MPI_TASKS wfreq.x -nimage $NIMAGE < wfreq.in > wfreq.out


Structure of the input data (wfreq.in):
===============================================================================

&INPUT_WEST
  qe_prefix="pwscf"
  west_prefix="west"
  outdir="./"
/
&WSTAT_CONTROL
  wstat_calculation="S"
  n_pdep_eigen=4
/
&WFREQ_CONTROL
  wfreq_calculation="XWGQ"
  n_pdep_eigen_to_use=2
  qp_bandrange(1)=1
  qp_bandrange(2)=2
  macropol_calculation="N"
  n_lanczos=20
  n_imfreq=10
  n_refreq=10
  ecut_imfreq=100.0
  ecut_refreq=2.0
/
   

Namelist: &WSTAT_CONTROL

wstat_calculation CHARACTER
Default: 'S'
Status: REQUIRED
 Available options are:
            
'S' :
 Start from scratch.
            
'R' :
 Restart from an interrupted run. You should restart with the
same number of cores.
            
n_pdep_eigen INTEGER
Default: '4'
Status: REQUIRED
 Number of PDEP eigenpotentials.
         
n_pdep_times INTEGER
Default: 4
Status: OPTIONAL
 Maximum dimension of the search space = n_pdep_eigen * n_pdep_times.
         
n_pdep_maxiter INTEGER
Default: 100
Status: OPTIONAL
 Maximum number of iterations in PDEP.
         
n_dfpt_maxiter INTEGER
Default: 250
Status: OPTIONAL
 Maximum number of iterations in DFPT.
         
n_pdep_read_from_file INTEGER
Default: 0
Status: OPTIONAL
 Number of PDEP eigenpotentials that can be read from file.
         
trev_pdep REAL
Default: 1.D-3
Status: OPTIONAL
 Absolute convergence threshold in the PDEP eigenvalues.
         
trev_pdep_rel REAL
Default: 1.D-1
Status: OPTIONAL
 Relative convergence threshold in the PDEP eigenvalues.
         
tr2_dfpt REAL
Default: 1.D-12
Status: OPTIONAL
 Convergence threshold in DFPT. Note that in the first PDEP iterations
a reduced threshold for DFPT could be used by the code in order to speed up the computation.
         
l_minimize_exx_if_active LOGICAL
Default: .FALSE.
Status: OPTIONAL
 If (.TRUE.), then the exx term in the Hamiltonian is reduced as much as possible.
         
l_kinetic_only LOGICAL
Default: .FALSE.
Status: OPTIONAL
 If (.TRUE.), then only the kinetic term in the Hamiltonian is kept.
         
l_use_ecutrho LOGICAL
Default: .FALSE.
Status: OPTIONAL
 If (.TRUE.), then the eigenpotentials are represented with ecutrho instead of ecutwfc.
         

Namelist: &WFREQ_CONTROL

wfreq_calculation CHARACTER
Default: 'XWGQ'
Status: REQUIRED
 Available options are:
            
'XWGQ' :
 Compute the QP corrections.
            
'XwGQ' :
 Compute the QP corrections, restart from an interrupted / just read W run.
            
'XwgQ' :
 Compute the QP corrections, restart from an interrupted / just read G run.
            
'X' :
 Compute the HF corrections.
            
'XWO' :
 Compute the optical properties.
            
'XWGQP' :
 Compute the QP corrections, and plot spectral functions.
            
'XWGQOP' :
 Compute all.
            
n_pdep_eigen_to_use INTEGER
Default: 2
Status: REQUIRED
 Number of PDEP eigenvectors to use in Wfreq. They are read from previous Wstat run.
This value cannot exceed n_pdep_eigen (defined in wstat_control) and is used
to check the convergence of the calculation.
         
qp_bandrange(i), i=1,2 INTEGER
Default: 1,2
Status: REQUIRED
 Compute the QP corrections from band qp_bandrange(1) to band qp_bandrange(2).
         
macropol_calculation CHARACTER
Default: 'N'
Status: REQUIRED
 Available options are:
            
'N' :
 None. Choice valid for isolated systems.
            
'C' :
 Include long-wavelength limit. Choice valid for condensed systems.
            
n_lanczos INTEGER
Default: 20
Status: REQUIRED
 Number of Lanczos chains.
         
n_imfreq INTEGER
Default: 10
Status: REQUIRED
 Number of frequecies used to sample the imaginary frequency axis in [0,ecut_imfreq].
         
n_refreq INTEGER
Default: 10
Status: REQUIRED
 Number of frequecies used to sample the real frequency axis in [0,ecut_refreq].
         
ecut_imfreq REAL
Default: 1.D0 Ry
Status: REQUIRED
 Cutoff for the imaginary frequencies.
         
ecut_refreq REAL
Default: 2.D0 Ry
Status: REQUIRED
 Cutoff for the real frequencies.
         
wfreq_eta REAL
Default: 0.003675D0 Ry
Status: OPTIONAL
 Pole shift.
         
n_secant_maxiter INTEGER
Default: 1
Status: OPTIONAL
 Maximum number of iterations in the secant solver.
         
trev_secant REAL
Default: 0.003675D0 Ry
Status: OPTIONAL
 Convergence threshold for the secant solver.
         
l_enable_lanczos LOGICAL
Default: .TRUE.
Status: OPTIONAL
 IF (.FALSE.), then Lanczos solvers are turned off.
         
o_restart_time REAL
Default: 0.D0 min
Status: OPTIONAL
 IF ( o_restart_time == 0 ) A checkpoint is written at every iteration of the W and G loops.
IF ( o_restart_time >  0 ) A checkpoint is written every o_restart_time minutes in the W and G loops.
IF ( o_restart_time <  0 ) A checkpoint is NEVER written in the W and G loops. Restart will not be possible.
         
ecut_spectralf(i), i=1,2 REAL
Default: -2.D0 Ry, 2.D0 Ry
Status: OPTIONAL
 Cutoff for the real frequencies.
         
n_spectralf INTEGER
Default: 10
Status: OPTIONAL
 Number of frequecies used to plot the spectral function, sampling
the interval [-ecut_spectralf(1),ecut_spectralf(2)].
         
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