Can the NEB be run with deactivated IMAGES-tag

[Yuli63]

To run NEB for a few 0*/ directories in parallel required large number of CPUs. Is it possible to submit the jobs from each 0*/ separately? Thank you.

[graeme]

no

[arup]

To solve this issue i used the following way and faced one confusion.

Parallel node run
1) I made six images using nebmake.pl
I ran the NEB parallely using six nodes and got the TS.

Single node run
1) I made one more directory (read 'one') where i have copied the generated 01 directory. Following the same way i have made 'two' and copied 02 there as 01. Same way i copied 03, 04, 05 ,06 to the 'three', 'four', 'five', 'six' as 01. Now, 00 and 07 directories are copied to 'one', 'two' ......'six' as 00 and 02.
2) Now, i ran the NEB calculation in each 'one', 'two', 'three', ..... separately using single node on each and got the TS.

But, activation barrier is high (about by 0.5 eV) when i ran in single node than parallel run. But, it should same. What could be possible reason and which way is correct to calculate NEB.

Thanks

[graeme]

It just doesn't make sense to run single image NEB calculations. The minimum energy path is a non-local object and is found by the collective optimization of all images together.

[berna_akgenc]

Dear All,

I don't understand what does it mean of single run?

This is my receipt to get minimum energy pathways as implemented in NEB.
1. I am creating my sub-directions files via "nebmake.pl POSCAR00 POSCAR06 5" command. The program create 5 different type POSCAR file in those directories.
2. Copy INCAR KPOINTS and POTCAR file to sub-directories (deleted SPRING, LCLIMB tag in INCAR file)
3. Run a job for every single directories.
4. Gain minimum energies versus number of images

I am confused right now, Am I doing right?
Thank you,
Berna

[graeme]

You are not. You use the script to make the directory structure as you said but then you run a single vasp calculation from the parent directory. Make sure to set the IMAGES tag in the INCAR file and run the calculation using a number of processors that is a multiple of the number of image. Vasp will then automatically go into the directories and run simultaneous calculations of each image to form the band.