[Pw_forum] NEB in QE 4.3: NaN values of some of the initially generated images

[Layla Martin-Samos]

Dear Torstein, nstep_path=0 produces a "strange behavior" as NEB starts
counting at 1. So if you just set nstep_path=1 it should work.

bests

Layla

2012/1/16 Torstein Fjermestad <torstein.fjermestad at kjemi.uio.no>

> Dear all,
>
> I have recently made several attempts to submit a NEB calculation using
> Quantum Espresso version 4.3.
> Unfortunately, every attempt fails with the program printing NaN values
> instead of the Cartesian coordinates for some of the initial images. For
> instance, in the .path file corresponding to the attached input file, image
> 3 and 4 (num_of_images=5) consists entirely of NaN values instead of real
> Cartesian coordinates. Of cause, if some of the initial images consist only
> of NaN values the calculation has no chance of continuing.
>
> There have been significant changes in the way to submit a NEB calculation
> between version 4.2.1 and version 4.3, and to test whether the same
> behavior would occur in version 4.2.1, I submitted a NEB calculation with
> QE version 4.2.1 with exactly the same input structures. In that case the
> program had no problem in generating the initial images. Because of this I
> think we can exclude the possibility of the error being caused by the input
> coordinates themselves.
>
> In the script I used to submit the calculation, the line to run the neb.x
> executable is the following:
>
> mpirun -np 16 -npernode 8 neb.x -inp neb_11.inp > neb_11.out
>
>
> Have any of you come across a similar problem before?
> Does anyone have suggestions on how to prevent the NaN values from
> appearing?
>
> Thanks in advance.
>
> Yours sincerely
>
> Torstein Fjermestad
> University of Oslo,
> Norway.
>
>
>
>
>
>
>
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