*** FILE AUTOMATICALLY CREATED: DO NOT EDIT, CHANGES WILL BE LOST ***

------------------------------------------------------------------------
INPUT FILE DESCRIPTION

Program: ph.x / PWscf / Quantum Espresso (version: 6.6)
------------------------------------------------------------------------


Input data format: { } = optional, [ ] = it depends, # = comment

Structure of the input data:
===============================================================================

title_line

&INPUTPH
   ...
/

[ xq(1) xq(2) xq(3) ]                        # if "ldisp" != .true.  and  "qplot" != .true.

[ nqs                                        # if "qplot" == .true.
  xq(1,i)    xq(2,i)    xq(3,1)    nq(1)
  ...
  xq(1,nqs)  xq(2,nqs)  xq(3,nqs)  nq(nqs) ]

[ atom(1)  atom(2)  ... atom(nat_todo) ]     # if "nat_todo" was specified



========================================================================
Line of input:

      title_line
   
   
   DESCRIPTION OF ITEMS:
   
      +--------------------------------------------------------------------
      Variable:       title_line
      
      Type:           CHARACTER
      Description:    Title of the job, i.e., a line that is reprinted on output.
      +--------------------------------------------------------------------
      
===End of line-of-input=================================================


========================================================================
NAMELIST: &INPUTPH

   +--------------------------------------------------------------------
   Variable:       amass(i), i=1,ntyp
   
   Type:           REAL
   Default:        0.0
   Description:    Atomic mass [amu] of each atomic type.
                   If not specified, masses are read from data file.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       outdir
   
   Type:           CHARACTER
   Default:        value of the ESPRESSO_TMPDIR environment variable if set;
                    current directory ('./') otherwise
   Description:    Directory containing input, output, and scratch files;
                   must be the same as specified in the calculation of
                   the unperturbed system.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       prefix
   
   Type:           CHARACTER
   Default:        'pwscf'
   Description:    Prepended to input/output filenames; must be the same
                   used in the calculation of unperturbed system.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       niter_ph
   
   Type:           INTEGER
   Default:        maxter=100
   Description:    Maximum number of iterations in a scf step. If you want
                   more than 100, edit variable "maxter" in PH/phcom.f90
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       tr2_ph
   
   Type:           REAL
   Default:        1e-12
   Description:    Threshold for self-consistency.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       alpha_mix(niter)
   
   Type:           REAL
   Default:        alpha_mix(1)=0.7
   Description:    Mixing factor (for each iteration) for updating
                   the scf potential:
                   
                   vnew(in) = alpha_mix*vold(out) + (1-alpha_mix)*vold(in)
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       nmix_ph
   
   Type:           INTEGER
   Default:        4
   Description:    Number of iterations used in potential mixing.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       verbosity
   
   Type:           CHARACTER
   Default:        'default'
   Description:   
                   Options are:
    
                   'debug', 'high', 'medium' :
                        verbose output
    
                   'low', 'default', 'minimal' :
                        short output
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       reduce_io
   
   Type:           LOGICAL
   Default:        .false.
   Description:    Reduce I/O to the strict minimum.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       max_seconds
   
   Type:           REAL
   Default:        1.d7
   Description:    Maximum allowed run time before the job stops smoothly.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       fildyn
   
   Type:           CHARACTER
   Default:        'matdyn'
   Description:    File where the dynamical matrix is written.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       fildrho
   
   Type:           CHARACTER
   Default:        ' '
   Description:    File where the charge density responses are written. Note that the file
                   will actually be saved as ${outdir}/_ph0/${prefix}.${fildrho}1
                   where  ${outdir}, ${prefix} and ${fildrho} are the values of the
                   corresponding input variables
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       fildvscf
   
   Type:           CHARACTER
   Default:        ' '
   Description:    File where the the potential variation is written
                   (for later use in electron-phonon calculation, see also fildrho).
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       epsil
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. in a q=0 calculation for a non metal the
                   macroscopic dielectric constant of the system is
                   computed. Do not set "epsil" to .true. if you have a
                   metallic system or q/=0: the code will complain and stop.
                   
                   Note: the input value of "epsil" will be ignored if "ldisp"=.true.
                   (the code will automatically set "epsil" to .false. for metals,
                   to .true. for insulators: see routine PHonon/PH/prepare_q.f90).
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       lrpa
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. the dielectric constant is calculated at the
                   RPA level with DV_xc=0.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       lnoloc
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. the dielectric constant is calculated without
                   local fields, i.e. by setting DV_H=0 and DV_xc=0.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       trans
   
   Type:           LOGICAL
   Default:        .true.
   Description:    If .true. the phonons are computed.
                   If "trans" .and. "epsil" are .true. effective charges are
                   calculated.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       lraman
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. calculate non-resonant Raman coefficients
                   using second-order response as in:
                   M. Lazzeri and F. Mauri, PRL 90, 036401 (2003).
   +--------------------------------------------------------------------
   
   ///---
      OPTIONAL VARIABLES FOR RAMAN:
      
      +--------------------------------------------------------------------
      Variable:       eth_rps
      
      Type:           REAL
      Default:        1.0d-9
      Description:    Threshold for calculation of  Pc R |psi>.
      +--------------------------------------------------------------------
      
      +--------------------------------------------------------------------
      Variable:       eth_ns
      
      Type:           REAL
      Default:        1.0e-12
      Description:    Threshold for non-scf wavefunction calculation.
      +--------------------------------------------------------------------
      
      +--------------------------------------------------------------------
      Variable:       dek
      
      Type:           REAL
      Default:        1.0e-3
      Description:    Delta_xk used for wavefunction derivation wrt k.
      +--------------------------------------------------------------------
      
   \\\---
   
   +--------------------------------------------------------------------
   Variable:       recover
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. restart from an interrupted run.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       low_directory_check
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. search in the phsave directory only the
                                    quantities requested in input.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       only_init
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. only the bands and other initialization quantities are calculated.
                   (used for GRID parallelization)
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       qplot
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. a list of q points is read from input.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       q2d
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. three q points and relative weights are
                   read from input. The three q points define the rectangle
                   q(:,1) + l (q(:,2)-q(:,1)) + m (q(:,3)-q(:,1)) where
                   0< l,m < 1. The weights are integer and those of points two
                   and three are the number of points in the two directions.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       q_in_band_form
   
   Type:           LOGICAL
   Default:        .false.
   Description:    This flag is used only when qplot is .true. and q2d is
                   .false.. When .true. each couple of q points q(:,i+1) and
                   q(:,i) define the line from q(:,i) to q(:,i+1) and nq
                   points are generated along that line. nq is the weigth of
                   q(:,i). When .false. only the list of q points given as
                   input is calculated. The weights are not used.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       electron_phonon
   
   Type:           CHARACTER
   Default:        ' '
   Description:   
                   Options are:
    
                   'simple' :
                        Electron-phonon lambda coefficients are computed
                        for a given q and a grid of k-points specified by
                        the variables nk1, nk2, nk3, k1, k2, k3.
    
                   'interpolated' :
                        Electron-phonon is calculated by interpolation
                        over the Brillouin Zone as in M. Wierzbowska, et
                        al. arXiv:cond-mat/0504077
    
                   'lambda_tetra' :
                        The electron-phonon coefficient \lambda_{q \nu}
                        is calculated with the optimized tetrahedron method.
    
                   'gamma_tetra' :
                        The phonon linewidth \gamma_{q \nu} is calculated
                        from the electron-phonon interactions
                        using the optimized tetrahedron method.
    
                   'epa' :
                        Electron-phonon coupling matrix elements are written
                        to file prefix.epa.k for further processing by program
                        epa.x which implements electron-phonon averaged (EPA)
                        approximation as described in G. Samsonidze & B. Kozinsky,
                        Adv. Energy Mater. 2018, 1800246 doi:10.1002/aenm.201800246
                        arXiv:1511.08115
    
                   'ahc' :
                        Quantities required for the calculation of phonon-induced
                        electron self-energy are computed and written to the directory
                        "ahc_dir". The output files can be read by postahc.x for
                        the calculation of electron self-energy.
                        Available for both metals and insulators.
                        "trans"=.false. is required.
    
                   For metals only, requires gaussian smearing (except for 'ahc').
                   
                   If "trans"=.true., the lambdas are calculated in the same
                   run, using the same k-point grid for phonons and lambdas.
                   If "trans"=.false., the lambdas are calculated using
                   previously saved DeltaVscf in "fildvscf", previously saved
                   dynamical matrix, and the present punch file. This allows
                   the use of a different (larger) k-point grid.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       el_ph_nsigma
   
   Type:           INTEGER
   Default:        10
   Description:    The number of double-delta smearing values used in an
                   electron-phonon coupling calculation.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       el_ph_sigma
   
   Type:           REAL
   Default:        0.02
   Description:    The spacing between double-delta smearing values used in
                   an electron-phonon coupling calculation.
   +--------------------------------------------------------------------
   
   ///---
      VARIABLES FOR "ELECTRON_PHONON" = 'AHC':
      
      +--------------------------------------------------------------------
      Variable:       ahc_dir
      
      Type:           CHARACTER
      Default:        outdir // 'ahc_dir/'
      Description:    Directory where the output binary files are written.
      +--------------------------------------------------------------------
      
      +--------------------------------------------------------------------
      Variable:       ahc_nbnd
      
      Type:           INTEGER
      Status:         REQUIRED
      Description:    Number of bands for which the electron self-energy is to be computed.
      +--------------------------------------------------------------------
      
      +--------------------------------------------------------------------
      Variable:       ahc_nbndskip
      
      Type:           INTEGER
      Default:        0
      Description:    Number of bands to exclude when computing the self-energy. Self-energy
                      is computed for bands with indices from "ahc_nbndskip"+1 to
                      "ahc_nbndskip"+"ahc_nbnd". "ahc_nbndskip"+"ahc_nbnd" cannot
                      exceed nbnd of the preceding SCF or NSCF calculation.
      +--------------------------------------------------------------------
      
      +--------------------------------------------------------------------
      Variable:       skip_upperfan
      
      Type:           LOGICAL
      Default:        .false.
      Description:    If .true., skip calculation of the upper Fan self-energy, which
                      involves solving the Sternheimer equation.
      +--------------------------------------------------------------------
      
   \\\---
   
   +--------------------------------------------------------------------
   Variable:       lshift_q
   
   Type:           LOGICAL
   Default:        .false.
   Description:    Use a wave-vector grid displaced by half a grid step
                   in each direction - meaningful only when ldisp is .true.
                   When this option is set, the q2r.x code cannot be used.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       zeu
   
   Type:           LOGICAL
   Default:        zeu="epsil"
   Description:    If .true. in a q=0 calculation for a non metal the
                   effective charges are computed from the dielectric
                   response. This is the default algorithm. If "epsil"=.true.
                   and "zeu"=.false. only the dielectric tensor is calculated.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       zue
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. in a q=0 calculation for a non metal the
                   effective charges are computed from the phonon
                   density responses. This is an alternative algorithm,
                   different from the default one (if "trans" .and. "epsil" )
                   The results should be the same within numerical noise.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       elop
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. calculate electro-optic tensor.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       fpol
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. calculate dynamic polarizabilities
                   Requires "epsil"=.true. ( experimental stage:
                   see example09 for calculation of methane ).
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       ldisp
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. the run calculates phonons for a grid of
                   q-points specified by "nq1", "nq2", "nq3" - for direct
                   calculation of the entire phonon dispersion.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       nogg
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. disable the "gamma_gamma" trick used to speed
                   up calculations at q=0 (phonon wavevector) if the sum over
                   the Brillouin Zone includes k=0 only. The gamma_gamma
                   trick exploits symmetry and acoustic sum rule to reduce
                   the number of linear response calculations to the strict
                   minimum, as it is done in code phcg.x.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       asr
   
   Type:           LOGICAL
   Default:        .false.
   Description:    Apply Acoustic Sum Rule to dynamical matrix, effective charges
                   Works only in conjunction with "gamma_gamma" tricks (see above)
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       ldiag
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. forces the diagonalization of the dynamical
                   matrix also when only a part of the dynamical matrix
                   has been calculated. It is used together with "start_irr"
                   and "last_irr". If all modes corresponding to a
                   given irreducible representation have been calculated,
                   the phonon frequencies of that representation are
                   correct. The others are zero or wrong. Use with care.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       lqdir
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. ph.x creates inside outdir a separate subdirectory
                   for each q vector. The flag is set to .true. when "ldisp"=.true.
                   and "fildvscf" /= ' ' or when an electron-phonon
                   calculation is performed. The induced potential is saved
                   separately for each q inside the subdirectories.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       search_sym
   
   Type:           LOGICAL
   Default:        .true.
   Description:    Set it to .false. if you want to disable the mode
                   symmetry analysis.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variables:      nq1, nq2, nq3
   
   Type:           INTEGER
   Default:        0,0,0
   Description:    Parameters of the Monkhorst-Pack grid (no offset) used
                   when @ref ldisp=.true. Same meaning as for nk1, nk2, nk3
                   in the input of pw.x.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variables:      nk1, nk2, nk3, k1, k2, k3
   
   Type:           INTEGER
   Default:        0,0,0,0,0,0
   Description:    When these parameters are specified the phonon program
                   runs a pw non-self consistent calculation with a different
                   k-point grid thant that used for the charge density.
                   This occurs even in the Gamma case.
                   nk1,nk2,nk3 are the parameters of the Monkhorst-Pack grid
                   with offset determined by k1,k2,k3.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       diagonalization
   
   Type:           CHARACTER
   Default:        'david'
   Description:   
                   Diagonalization method for the non-SCF calculations.
    
                   'david' :
                        Davidson iterative diagonalization with overlap matrix
                        (default). Fast, may in some rare cases fail.
    
                   'cg' :
                        Conjugate-gradient-like band-by-band diagonalization.
                        Slower than 'david' but uses less memory and is
                        (a little bit) more robust.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       read_dns_bare
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true. the PH code tries to read three files in the DFPT+U
                   calculation: dns_orth, dns_bare, d2ns_bare.
                   dns_orth and dns_bare are the first-order variations of
                   the occupation matrix, while d2ns_bare is the second-order
                   variation of the occupation matrix. These matrices are
                   computed only once during the DFPT+U calculation. However,
                   their calculation (especially of d2ns_bare) is computationally
                   expensive, this is why they are written to file and then can be
                   read (e.g. for restart) in order to save time.
   +--------------------------------------------------------------------
   
   +--------------------------------------------------------------------
   Variable:       ldvscf_interpolate
   
   Type:           LOGICAL
   Default:        .false.
   Description:    If .true., use Fourier interpolation of phonon potential
                   to compute the induced part of phonon potential at each
                   q point. Results of a dvscf_q2r.x run is needed.
                   Requires "trans" = .false..
   +--------------------------------------------------------------------
   
   ///---
      OPTIONAL VARIABLES FOR DVSCF INTERPOLATION:
      
      +--------------------------------------------------------------------
      Variable:       wpot_dir
      
      Type:           CHARACTER
      Default:        outdir // 'w_pot/'
      Description:    Directory where the w_pot binary files are written.
                      Must be the same with wpot_dir used in dvscf_q2r.x.
                      The real space potential files are stored in wpot_dir
                      with names ${prefix}.wpot.irc${irc}//"1".
      +--------------------------------------------------------------------
      
      +--------------------------------------------------------------------
      Variable:       do_long_range
      
      Type:           LOGICAL
      Default:        .false.
      Description:    If .true., add the long-range part of the potential
                      to the Fourier interpolated potential as in:
                      S. Ponce et al, J. Chem. Phys. 143, 102813 (2015).
                      Reads dielectric matrix and Born effective charges from
                      the ${wpot_dir}/tensors.dat file, written in dvscf_q2r.x.
                      Currently, only the dipole (Frohlich) part is implemented.
                      The quadrupole part is not implemented.
      +--------------------------------------------------------------------
      
      +--------------------------------------------------------------------
      Variable:       do_charge_neutral
      
      Type:           LOGICAL
      Default:        .false.
      Description:    If .true., impose charge neutrality on the Born effective
                      charges. Used only if "do_long_range" = .true..
      +--------------------------------------------------------------------
      
   \\\---
   
   ///---
      SPECIFICATION OF IRREDUCIBLE REPRESENTATION
      
      +--------------------------------------------------------------------
      Variable:       start_irr
      
      Type:           INTEGER
      Default:        1
      See:            last_irr
      Description:    Perform calculations only from "start_irr" to "last_irr"
                      irreducible representations.
                      
                      IMPORTANT:
                         * "start_irr" must be <= 3*nat
                         * do not specify "nat_todo" together with
                           "start_irr", "last_irr"
      +--------------------------------------------------------------------
      
      +--------------------------------------------------------------------
      Variable:       last_irr
      
      Type:           INTEGER
      Default:        3*nat
      See:            start_irr
      Description:    Perform calculations only from "start_irr" to "last_irr"
                      irreducible representations.
                      
                      IMPORTANT:
                         * "start_irr" must be <= 3*nat
                         * do not specify "nat_todo" together with
                           "start_irr", "last_irr"
      +--------------------------------------------------------------------
      
      +--------------------------------------------------------------------
      Variable:       nat_todo
      
      Type:           INTEGER
      Default:        0, i.e. displace all atoms
      Description:    Choose the subset of atoms to be used in the linear response
                      calculation: "nat_todo" atoms, specified in input (see below)
                      are displaced. Can be used to estimate modes for a molecule
                      adsorbed over a surface without performing a full fledged
                      calculation. Use with care, at your own risk, and be aware
                      that this is an approximation and may not work.
                      IMPORTANT:
                         * "nat_todo" <= nat
                         * if linear-response is calculated for a given atom, it
                           should also be done for all symmetry-equivalent atoms,
                           or else you will get incorrect results
      +--------------------------------------------------------------------
      
      +--------------------------------------------------------------------
      Variable:       modenum
      
      Type:           INTEGER
      Default:        0
      Description:    For single-mode phonon calculation : modenum is the index of the
                      irreducible representation (irrep) into which the reducible
                      representation formed by the 3*nat atomic displacements are
                      decomposed in order to perform the phonon calculation.
                      Note that a single-mode calculation will not give you the
                      frequency of a single phonon mode: in general, the selected
                      "modenum" is not an eigenvector. What you get on output is
                      a column of the dynamical matrix.
      +--------------------------------------------------------------------
      
   \\\---
   
   ///---
      Q-POINT SPECIFICATION
      
      +--------------------------------------------------------------------
      Variable:       start_q
      
      Type:           INTEGER
      Default:        1
      See:            last_q
      Description:    Used only when ldisp=.true..
                      Computes only the q points from "start_q" to "last_q".
                      
                      IMPORTANT:
                         * "start_q" must be <= "nqs" (number of q points found)
                         * do not specify "nat_todo" together with
                           "start_q", "last_q"
      +--------------------------------------------------------------------
      
      +--------------------------------------------------------------------
      Variable:       last_q
      
      Type:           INTEGER
      Default:        number of q points
      See:            start_q
      Description:    Used only when "ldisp"=.true..
                      Computes only the q points from "start_q" to "last_q".
                      
                      IMPORTANT
                         * "last_q" must be <= "nqs" (number of q points)
                         * do not specify "nat_todo" together with
                           "start_q", "last_q"
      +--------------------------------------------------------------------
      
      +--------------------------------------------------------------------
      Variable:       dvscf_star
      
      Type:           STRUCTURE
      Default:        disabled
      Description:    It contains the following components:
                      
                      dvscf_star%open  (logical, default: .false.)
                      dvscf_star%dir   (character, default: outdir//"Rotated_DVSCF" or the
                                        ESPRESSO_FILDVSCF_DIR environment variable)
                      dvscf_star%ext   (character, default: "dvscf") the extension to use
                                        for the name of the output files, see below
                      dvscf_star%basis (character, default: "cartesian") the basis on which
                                        the rotated dvscf will be saved
                      dvscf_star%pat   (logical, default: false) save an optional file with the
                                        displacement patterns and q vector for each dvscf file
                      
                      IF dvscf_star%open is .true. use symmetry to compute and store the variation
                      of the self-consistent potential on every q* in the star of the present q.
                      
                      The rotated dvscf will then be stored in directory dvscf_star%dir with name
                      prefix.dvscf_star%ext.q_name//"1". Where q_name is derived from the coordinates
                      of the q-point, expressed as fractions in crystalline coordinates
                      (notice that ph.x reads q-points in cartesian coordinates).
                      E.g. q_cryst= (0, 0.5, -0.25) -> q_name = "0_1o2_-1o4"
                      
                      The dvscf can be represented on a basis of cartesian 1-atom displacements
                      (dvscf_star%basis='cartesian') or on the basis of the modes at the rotated q-point
                      (dvscf_star%basis='modes'). Notice that the el-ph wannier code requires 'cartesian'.
                      Each dvscf file comes with a corresponding pattern file with an additional ".pat"
                      suffix; this file contains information about the basis and the q-point of the dvscf.
                      
                      Note: rotating dvscf can require a large amount of RAM memory and can be i/o
                            intensive; in its current implementation all the operations are done
                            on a single processor.
                      Note2: this feature is currently untested with image parallelisation.
      +--------------------------------------------------------------------
      
      +--------------------------------------------------------------------
      Variable:       drho_star
      
      Type:           STRUCTURE
      See:            dvscf_star
      Default:        disabled
      Description:    It contains the following components:
                      
                      drho_star%open  (logical, default: .false.)
                      drho_star%dir   (character, default: outdir//"Rotated_DRHO" or the
                                       ESPRESSO_FILDRHO_DIR environment variable)
                      drho_star%ext   (character, default: "drho") the extension to use
                                       for the name of the output files, see below
                      drho_star%basis (character, default: "modes") the basis on which
                                       the rotated drho will be saved
                      drho_star%pat   (logical, default: true) save an optional file with the
                                       displacement patterns and q vector for each drho file
                      
                      Like "dvscf_star", but for the perturbation of the charge density.
                      Notice that the defaults are different.
      +--------------------------------------------------------------------
      
   \\\---
   
===END OF NAMELIST======================================================


________________________________________________________________________
* IF ldisp != .true.   and   qplot != .true. : 

   ========================================================================
   Line of input:
   
         xq(1)  xq(2)  xq(3)
      
      
      DESCRIPTION OF ITEMS:
      
         +--------------------------------------------------------------------
         Variables:      xq(1)  xq(2)  xq(3)
         
         Type:           REAL
         Description:    The phonon wavevector, in units of 2pi/a0
                         (a0 = lattice parameter).
                         Not used if "ldisp"=.true. or "qplot"=.true.
         +--------------------------------------------------------------------
         
         
   ===End of line-of-input=================================================
   
   
    
* ELSE IF qplot == .true. : 

   SPECIFICATION OF Q POINTS WHEN "QPLOT" == .TRUE.
   
   ========================================================================
   CARD:  
   
      /////////////////////////////////////////
      // Syntax:                             //
      /////////////////////////////////////////
      
            nqs
            xq1(1)    xq2(1)    xq3(1)    nq(1)    
            xq1(2)    xq2(2)    xq3(2)    nq(2)    
            . . . 
            xq1(nqs)  xq2(nqs)  xq3(nqs)  nq(nqs)  
      
      /////////////////////////////////////////
      
      DESCRIPTION OF ITEMS:
      
         +--------------------------------------------------------------------
         Variable:       nqs
         
         Type:           INTEGER
         Description:    Number of q points in the list. Used only if "qplot"=.true.
         +--------------------------------------------------------------------
         
         +--------------------------------------------------------------------
         Variables:      xq1, xq2, xq3
         
         Type:           REAL
         Description:    q-point coordinates; used only with @ref ldisp=.true. and qplot=.true.
                         The phonon wavevector, in units of 2pi/a0 (a0 = lattice parameter).
                         The meaning of these q points and their weights nq depend on the
                         flags q2d and q_in_band_form. (NB: nq is integer)
         +--------------------------------------------------------------------
         
         +--------------------------------------------------------------------
         Variable:       nq
         
         Type:           INTEGER
         Description:    The weight of the q-point; the meaning of nq depends
                         on the flags q2d and q_in_band_form.
         +--------------------------------------------------------------------
         
   ===END OF CARD==========================================================
   
   
    
ENDIF
________________________________________________________________________

________________________________________________________________________
* IF nat_todo was specified : 

   ========================================================================
   Line of input:
   
         atom(1)  atom(2) ... atom(nat_todo)
      
      
      DESCRIPTION OF ITEMS:
      
         +--------------------------------------------------------------------
         Variables:      atom(1)  atom(2) ... atom(nat_todo)
         
         Type:           INTEGER
         Description:    Contains the list of indices of atoms used in the
                         calculation if "nat_todo" is specified.
         +--------------------------------------------------------------------
         
         
   ===End of line-of-input=================================================
   
   
    
ENDIF
________________________________________________________________________


::::  ADDITIONAL INFORMATION 

   NB: The program ph.x writes on the tmp_dir/_ph0/{prefix}.phsave directory
   a file for each representation of each q point. This file is called
   dynmat.#iq.#irr.xml where #iq is the number of the q point and #irr
   is the number of the representation. These files contain the
   contribution to the dynamical matrix of the irr representation for the
   iq point.
   
   If "recover"=.true. ph.x does not recalculate the
   representations already saved in the tmp_dir/_ph0/{prefix}.phsave
   directory.  Moreover ph.x writes on the files patterns.#iq.xml in the
   tmp_dir/_ph0/{prefix}.phsave directory the displacement patterns that it
   is using. If "recover"=.true. ph.x does not recalculate the
   displacement patterns found in the tmp_dir/_ph0/{prefix}.phsave directory.
   
   This mechanism allows:
   
     1) To recover part of the ph.x calculation even if the recover file
        or files are corrupted. You just remove the _ph0/{prefix}.recover
        files from the tmp_dir directory. You can also remove all the _ph0
        files and keep only the _ph0/{prefix}.phsave directory.
   
     2) To split a phonon calculation into several jobs for different
        machines (or set of nodes). Each machine calculates a subset of
        the representations and saves its dynmat.#iq.#irr.xml files on
        its tmp_dir/_ph0/{prefix}.phsave directory. Then you collect all the
        dynmat.#iq.#irr.xml files in one directory and run ph.x to
        collect all the dynamical matrices and diagonalize them.
   
   NB: To split the q points in different machines, use the input
   variables start_q and last_q. To split the irreducible
   representations, use the input variables "start_irr", "last_irr". Please
   note that different machines will use, in general, different
   displacement patterns and it is not possible to recollect partial
   dynamical matrices generated with different displacement patterns.  A
   calculation split into different machines will run as follows: A
   preparatory run of ph.x with "start_irr"=0, "last_irr"=0 produces the sets
   of displacement patterns and save them on the patterns.#iq.xml files.
   These files are copied in all the tmp_dir/_ph0/{prefix}.phsave directories
   of the machines where you plan to run ph.x. ph.x is run in different
   machines with complementary sets of start_q, last_q, "start_irr" and
   "last_irr" variables.  All the files dynmat.#iq.#irr.xml are
   collected on a single tmp_dir/_ph0/{prefix}.phsave directory (remember to
   collect also dynmat.#iq.0.xml).  A final run of ph.x in this
   machine collects all the data contained in the files and diagonalizes
   the dynamical matrices.  This is done requesting a complete dispersion
   calculation without using start_q, last_q, "start_irr", or "last_irr".
   See an example in examples/GRID_example.
   
   On parallel machines the q point and the irreps calculations can be split
   automatically using the -nimage flag. See the phonon user guide for further
   information.
   

This file has been created by helpdoc utility on Wed Dec 02 08:04:43 CET 2020
