[Pw_forum] Phonon crash

[Miguel Martínez Canales]

Dear fellows,

I have found that, when running a phonon calculation under certain 
conditions, it crashes. More concretely, on fcc systems (I haven't checked 
diamond structures) if the scf run uses a 20 20 20 monkhorst-pack grid and 
the phonon calculation uses ldisp=.true. for a 8*8*8 regular grid the 
phonon run will crash at dyn23 (q = 0.625 -0.375  0.875). The last lines of 
the phonon output are:

      Calculation of q =   0.6250 -0.3750  0.8750

 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
      from set_kplusq : error #     32000
      too many k points
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

      stopping ...

It really puzzles me that it stops on the 23rd point, and not sooner. Maybe 
it's related to the star of q?

If I specify this point by hand, doing a nscf run and then a phonon run at 
that qpoint, it will also crash. It depends neither on the lattice 
parametre, nor the the pseudpotential (I've done it with Na LDA, Li LDA and 
Li PBE). It won't crash if I reduce the k-point grid, and it won't crash 
with the same grid on a bcc lattice.

I am using espresso-3.2.1 plus the patch that Paolo submitted to make 
-npool work with ph.x. It's been compiled with ifort 8.1 and mkl 9.0 in an 
itanium 2 machine. Any ideas?

Thanks for your comments,

Miguel

In case the input is relevant, I attach it:


# self-consistent calculation
cat > na.scf.in << EOF
  &control
     calculation='scf'
     restart_mode='from_scratch',
     tstress = .true.
     tprnfor = .true.
     prefix='na',
     pseudo_dir = '$PSEUDO_DIR/',
     outdir='$TMP_DIR/'
  /
  &system
     ibrav=  2, celldm(1) = $alat , nat=  1, ntyp= 1,
     ecutwfc = 30.0
     occupations='smearing', smearing='m-p', degauss= 0.010
  /
  &electrons
     conv_thr =  1.0d-8
     mixing_beta = 0.7
  /
ATOMIC_SPECIES
  Na  22.989768  Na.pz-n-vbc.UPF
ATOMIC_POSITIONS
  Na 0.00 0.00 0.00
K_POINTS {automatic}
  20 20 20   1 1 1
EOF
$ECHO "  running the scf calculation...\c"
$PW_COMMAND < na.scf.in > na.scf.out
$ECHO " done"

# phonon calculation
cat > na.ph.in << EOF
phonons of Na
  &inputph
   tr2_ph=1.0d-16,
   prefix='na',
   ldisp=.true.,
   nq1=8, nq2=8, nq3=8
   amass(1)=22.989768,
   outdir='$TMP_DIR/',
   fildyn='na.dyn',
  /
EOF
$ECHO "  running the phonon calculation ...\c"
$PH_COMMAND < na.ph.in > na.ph.out
$ECHO " done"


-- 
----------------------------------------
Miguel Martínez Canales
Dto. Física de la Materia Condensada
UPV/EHU
Facultad de Ciencia y Tecnología
Apdo. 644
48080 Bilbao (Spain)
Fax:  +34 94 601 3500
Tlf:  +34 94 601 5437
----------------------------------------

  "If you have an apple and I have an apple and
  we exchange these apples then you and I will
  still each have one apple. But if you have an
  idea and I have an idea and we exchange these
  ideas, then each of us will have two ideas."

    George Bernard Shaw