UT theoretical chemistry code forum

Hi Prof. Graeme,

As my former post mentioned, I have to perform a dynamical matrix calculation for a big system. The job cannot be finished within the time limit of the supercomputer, e.g., 24 hours. Let's assume that the NSW = 31, if the first run has calculated 10 NSW steps, and I restart the job, will VASP calculate the remaining 21 NSW steps?

Thanks in advance.

Yes, you can continue a partially finished run. Take a look at the bottom of this page:
http://theory.cm.utexas.edu/vtsttools/dynmat/

Basically, you can zero the displacements that have been done, and run again, and then collect the results using dymmatrix.pl

Another possibility is to run the displacements in parallel. The information for doing this is on that same page. You can set the IMAGES tag so that different groups of processors work on different displacements. This is convenient if you can run on many processors at the same time.

Hi Prof. Graeme, I am not sure I understand your idea of "zero the displacements that have been done". Let's assume that there is a 5-atom molecule adsorbing onto the 10-atom slab, and I set displacement to 0.001 to the molecule but not to the slab, then the DISPLACECAR looks like:
0.001 0.001 0.001
0.001 0.001 0.001
0.001 0.001 0.001
0.001 0.001 0.001
0.001 0.001 0.001
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000

For a dynamical matrix calculation, I set NSW=3*5+1=16. After the first run, I have calculated 6 steps of 16. How do I "zero the displacements that have been done" in the DISPLACECAR file?

Thanks a lot.

Since you have done 5 displacements, your next DISPLACECAR should be:

0.000 0.000 0.000
0.000 0.000 0.001
0.001 0.001 0.001
0.001 0.001 0.001
0.001 0.001 0.001
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000

And NSW = (15-5)+1 = 11

Thank you so much, Prof. Graeme. I will try that.