[Pw_forum] drho and D3 calculations

[Jonathan Breeze]

Dear PWscf users,

I have been trying for a long time to calculate the 3rd order anharmonic 
coefficients at the Gamma point.
For a simple system like MgO using the following file for pw.x:

Mgo
Magnesium Oxide
 &control
    calculation='scf'
    restart_mode='from_scratch',
    prefix='mgo',
    pseudo_dir = '/usr/people/breezejd/pwscf/pwscf-parallel/pots/',
    outdir='/usr/people/breezejd/pwscf/pwscf-parallel/tmp/'
 /
 &system   
    ibrav=  2, celldm(1) =7.27303, nat=  2, ntyp= 2,
    ecutwfc =44.0, occupations ='fixed',
 /
 &electrons
    conv_thr =  1.0d-8
    mixing_beta = 0.7
 /
ATOMIC_SPECIES
 Mg  24.3050 Mg.pz-vbc.UPF
 O   15.9994 O.pz-mt.UPF
ATOMIC_POSITIONS
 Mg 0.00 0.00 0.00
 O  0.50 0.50 0.50
K_POINTS{automatic}
 4,4,4,0,0,0

Everything goes well after the SCF calculation. I then run the phonon 
code at the Gamma point to produce a drho file.  

phonons of MgO at Gamma
 &inputph
  iverbosity=1,
  prefix='mgo',
  amass(1)=24.305,
  amass(2)=15.9994,
  tmp_dir='/usr/people/breezejd/pwscf/pwscf-parallel/tmp/',
  fildrho='mgo.drhoG',
  fildyn='mgo.dynG',
 /
0.0 0.0 0.0

Phonon produces the dynamical matrix which seems ok and four drho files: 
mgo.drho, mgo.drhoG1, mgo.drhoG2, mgo.drhoG3.  

mgo.drho look like this: which seems a little truncated.
                                                                          
      24      24      24      24      24      24       2       2
     2  7.27303000  0.00000000  0.00000000  0.00000000  0.00000000  
0.00000000
      235.8216583131        4.0000000000       44.0000000000     0
    1      Mg     2.00     0.0000000000  0.0000000000  0.0000000000
    2      O      6.00     0.5000000000  0.5000000000  0.5000000000
 13824*0.E+0


The  other three are quite large (about 210K).  I have no idea what the 
numbers in these files mean.

Anyway, I have tried to run D3, the input file for this is:

third order derivatives of dynamical matrix for MgO at Gamma
 &inputph
  iverbosity=1,
  tmp_dir='/usr/people/breezejd/pwscf/pwscf-parallel/tmp/',
  filpun='mgo.pun',
  fildyn='mgo.d3dyn',
  fildrho='mgo.drhoG',
  fild0rho='mgo.drhoG',
  amass(1)=24.3050,
  amass(2)=15.9994,
 /
0.0 0.0 0.0

The cards load in OK but then I get an error;


     Program D3TOTEN1.2.0 starts ...
     Today is  6Jun2003 at  7:47:46

     Parallel version (MPI)
     Number of processors in use:      1

     UltraSoft (Vanderbilt) Pseudopotentials
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     from saveall : error #        21
     reading file
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     stopping ...

I'm sorry for this long email, but I have tried posting on the forum a 
number of times and I have never received a single response.  
I am running short of time now on the project and may have to abandon 
using the D3 (2n+1) method in favour of another method such as frozen 
phonon.

Please help!!!

Yours pleadingly,

Jonathan Breeze