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

[Torstein Fjermestad]

 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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