Dear developers and users,

I would like to ask whether it is possible to restart a vibrational calculation that is performed using the dynamical matrix tools, e.g. when it crashed or is terminated. The reason for my question is that I am performing large vibrational calculations with many degrees of freedom which might not finish in one run. If I do these calculations using the VASP built-in functions, there is no way to restart the calculation using the already calculated displacements.

How does it work with the dynamical matrix tools? Thanks a lot!

Best, Berit

## Restarting a vibrational calculation using dynmat tools?

**Moderator:** moderators

You can restart a dynmat run. Say you have done 9 displacements out of a total of 15 (I'm just making these numbers up). The run can be continued by zeroing the completed displacements from the DISPLACECAR file, subtracting the total number of completed displacements from NSW (In this case NSW would be 16 originally, and now should be 7), and restart. To generate the full dynamical matrix from both runs, use the dynmatrix.pl script, and make sure to include both DISPLACECAR and OUTCAR files.

This technique can be used to combine the information from any number of runs. You can also then, for example, start many jobs at once, working on different displacements, and combine them afterwards.