[Pw_forum] Bug in NEB calculation with hybrid functionals

[hannu.komsa at epfl.ch]

Hi

I am trying to do a NEB-calculation using hybrid functionals (HSE).  
The first calculation, the first image, is calculated fine, but when  
starting the second image, QE crashed with the following error message:

   At line 228 of file exx.f90
   Fortran runtime error: Attempting to allocate already allocated array
    'index_xkq'

This line reads as:
      allocate ( index_xkq(nkstot,nqs) )
I could just add if(.not.allocated()) etc.. However, even with this,  
if the images have different number of k-points the calculation will  
end with a segmentation fault. So I guess it would be better to  
deallocate the arrays somewhere, but I don't know how to do this the  
best way.

The error was reproduced with intel and gnu compiler, with 4.3 and CVS  
version, and run in parallel or serial. Input file demonstrating the  
bug for an unrealistic system included below.


Best regards,
   Hannu-Pekka Komsa
   EPFL, Switzerland


BEGIN
BEGIN_PATH_INPUT
  &path
   restart_mode      = 'from_scratch'
   string_method     = 'neb',
   nstep_path        = 20,
   ds                = 2.D0,
   opt_scheme        = "broyden",
   num_of_images     = 5,
  /
END_PATH_INPUT
BEGIN_ENGINE_INPUT
  &control
     prefix='Si',
     pseudo_dir = './',
     outdir='./'
  /
  &system
     ibrav=  1, A = 5.465 , nat=  8, ntyp= 1,
     ecutwfc = 20,  nbnd =20,
     input_dft='hse', nqx1 = 1, nqx2 = 1, nqx3 = 1,
     exx_fraction = 0.25,
  /
  &electrons
     conv_thr = 1e-5,
  /
ATOMIC_SPECIES
  Si  28.086  Si.pbe-rrkj.UPF
BEGIN_POSITIONS
FIRST_IMAGE
ATOMIC_POSITIONS crystal
     Si    0.00 0.00 0.00 0 0 0
     Si    0.50 0.50 0.00 0 0 0
     Si    0.00 0.50 0.50 0 0 0
     Si    0.50 0.00 0.50 0 0 0
     Si    0.25 0.25 0.25
     Si    0.75 0.75 0.25 0 0 0
     Si    0.25 0.75 0.75 0 0 0
     Si    0.75 0.25 0.75 0 0 0
LAST_IMAGE
ATOMIC_POSITIONS crystal
Si       0.000000000   0.000000000   0.000000000    0   0   0
Si       0.500000000   0.500000000   0.000000000    0   0   0
Si       0.000000000   0.500000000   0.500000000    0   0   0
Si       0.500000000   0.000000000   0.500000000    0   0   0
Si       0.386058672   0.386058672   0.386058672
Si       0.750000000   0.750000000   0.250000000    0   0   0
Si       0.250000000   0.750000000   0.750000000    0   0   0
Si       0.750000000   0.250000000   0.750000000    0   0   0
END_POSITIONS
K_POINTS automatic
  2 2 2 1 1 1
END_ENGINE_INPUT
END