[Pw_forum] NEB error

[seunghwan lee]

Dear All,

I am having a trouble with running NEB calculation. I keep getting "cholesky decomposition error" for the first image during iteration #2

   from  pzpotrf  : error #         1
   problems computing cholesky decomposition

The problem occurs during the first SCF iteration. What's strange is that if I take the coordinates of image#1 and run SCF calculation, there is no problem. 

I usually change the coordinates a little if I have this problem during geometry optimization, but it doesn't look like that will solve the problem.

Here is the relevant part of my input file

 &system
    ibrav=6
    a=18.0
    b=18.0
    c=10.0012
    cosab=0.0
    cosac=0.0
    cosbc=0.0
    nat  = 82
    ntyp = 2
    ecutwfc = 20
    ecutrho = 240
    occupations = 'smearing'
    degauss = 0.01
    smearing = "cold"
    nspin = 2,
    starting_magnetization(1)=0.5
    starting_magnetization(2)=0.7
    nosym=.true.
 /
&electrons
    electron_maxstep = 200
    mixing_beta = 0.4
    conv_thr =  1.0d-7
    mixing_mode = 'plain'
 /
 &IONS
  CI_scheme         = "no-CI"
  ds                = 4.D0,
  num_of_images     = 10,
  opt_scheme        = "broyden",
  k_max             = 0.040D0,
  k_min             = 0.025D0,
  use_freezing      = .TRUE.,
  path_thr          = 0.08D0,
  bfgs_ndim         = 3,
  pot_extrapolation = "second_order",
  wfc_extrapolation = "second_order",
 /

Any advice will be appreciated.  Thank you.

Seunghwan Lee
University of North Carolina