[Pw_forum] ph.x: diagonalization (ZHEGV*) failed at some q-points

[Thomas Gruber]

Hello all,

I have done a phonon calculation for a fully relaxed system with QE 
4.3.2 and everything went fine. Then I increased the volume (~3%) and 
did a relax calculation:

&control
     calculation = 'relax'
     restart_mode='from_scratch',
     tstress = .true.
     tprnfor = .true.
     pseudo_dir = '/home/gruber/software/Espresso/espresso-4.3/pseudo/',
     outdir = './'
     forc_conv_thr = 1e-4
     etot_conv_thr = 1e-5
     wf_collect = .TRUE.
   /
&system
  ibrav=  0, A = 1, nat=  104, ntyp= 2,
     ecutwfc =70,
     occupations='smearing', smearing='methfessel-paxton', degauss=0.001
  /
&electrons
     conv_thr =  1.0d-8
  /
K_POINTS automatic
   4 4 4 0 0 0

Then I split my phonon calculation into several calculations:

&inputph
     tr2_ph=1.0d-15,
     recover=.true.
     ldisp=.true.,
     nq1=4,nq2=4,nq3=4,
     start_q=8,
     last_q=8,
     start_irr=27,
     last_irr=28,
     amass(1)=28.086,
     amass(2)=6.914,
     alpha_mix(1)=0.1,
/

For the first q-point it works, but for the last 2 q-points (maybe more) 
I get the following error message:
     Band Structure Calculation
      Davidson diagonalization with overlap

  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
      from cdiaghg : error #       868
      diagonalization (ZHEGV*) failed

Can someone tell me why and what I should do to get my representations?

Sincerely,

Thomas Gruber

-- 
Thomas Gruber
Institut für Theoretische Physik
TU Bergakademie Freiberg
Leipziger Str. 23, 09599 Freiberg, Germany
Tel: +49 (0)3731 392006
Email: thomas.gruber at physik.tu-freiberg.de