[Pw_forum] Strange pp.x output after vc-relax (v3.1)

[Steven Kirk]

Hello,

I have been trying to run a vc-relax calculation using pw.x (Q-E v3.1) 
to get a relaxed configuration of a unit cell at a specified external 
pressure, then dumping the relaxed cell configuration and charge density 
distribution using pp.x. My input data is below

pw.x input
==========
  &CONTROL
    title='iceXI calculation',
    calculation='vc-relax',
    restart_mode='from_scratch',
    prefix='iceXI',
    dt=30.0,
    nstep = 100,
    tstress = .true.,
    tprnfor = .true.
  /
  &SYSTEM
    ibrav = 8,
    A = 4.383, B = 7.623, C = 7.163, cosAB = 0, cosAC = 0, cosBC = 0,
    nat = 24,
    ntyp = 2,
    ecutwfc = 100.0
  /
  &ELECTRONS
  /
  &IONS
    ion_dynamics='damp'
  /
  &CELL
    cell_dynamics='damp-w',
    press = 100.0
    wmass = 0.0004
  /
ATOMIC_SPECIES
O 15.9994 O.pbe-rrkjus.UPF
H 1.00794 H.pbe-rrkjus.UPF
ATOMIC_POSITIONS {crystal}
O     0.00000    0.66600    0.05900
O     0.50000    0.16600    0.05900
O     0.00000    0.33400    0.55900
O     0.50000    0.83400    0.55900
O     0.50000    0.83300    0.93400
O     0.00000    0.33300    0.93400
O     0.50000    0.16700    0.43400
O     0.00000    0.66700    0.43400
H     0.68300    0.76800    0.98100
H     0.18300    0.26800    0.98100
H     0.31700    0.23200    0.48100
H    -0.18300    0.73200    0.48100
H     0.68300    0.23200    0.48100
H     0.18300    0.73200    0.48100
H     0.31700    0.76800    0.98100
H    -0.18300    0.26800    0.98100
H     0.00000    0.66400    0.19800
H     0.00000    0.54100    0.01700
H     0.50000    0.16400    0.19800
H     0.50000    0.04100    0.01700
H     0.00000    0.33600    0.69800
H     0.00000    0.45900    0.51700
H     0.50000    0.83600    0.69800
H     0.50000    0.95900    0.51700
K_POINTS automatic
4 4 4 0 0 0

pp.x input
==========
  &INPUTPP
                       prefix = 'iceXI' ,
                      filplot = 'iceXI.chdens' ,
                     plot_num = 0,
  /
  &PLOT
                        nfile = 1 ,
                    filepp(1) = 'iceXI.chdens',
                    weight(1) = 1.0,
                      fileout = 'iceXI.xsf' ,
                        iflag = 3 ,
                output_format = 3 ,
  /

===========

The problem is that the output cell parameters (at least) in the output 
.XSF file are the ORIGINAL cell parameters, not the RELAXED cell parameters.

What has gone wrong here ? Why doesn't my output XSF file contain the 
details for the relaxed cell ? Are the XSF lattice parameters , the XSF 
atomic coordinates or the 3D charge density grid wrong, or possibly all 
three?

Many thanks!

Steve Kirk

-- 
Dr. Steven R. Kirk           <Steven.Kirk at hv.se, S.R.Kirk at physics.org>
Dept. of Technology, Mathematics & Computer Science  (P)+46 520 223215
University West                                      (F)+46 520 223299
P.O. Box 957 Trollhattan 461 29 SWEDEN       http://taconet.webhop.org