How can WAVECAR be saved after every electronic cycle

[KWH]

Hello:

This has probably been addressed before but I couldn't find it. Is there same way to get VASP to save the WAVECAR file after each electronic convergence cycle? How about after each ionic cycle?

Best wishes

[ferenc_karsai]

VASP consists of a main ion loop. Within the ion loop the electronic convergence loop is called every ionic step.
The WAVECAR is written at the end of the ion loop if a stop criterion has been reached (last ionic cycle, premature stop by STOPCAR, etc.), or the wavefunctions on the TMPCAR file have been rotated, or LHFCALC=.TRUE.. In all cases the WAVECAR is overwritten by the last writeout.

You could try the following:
Use the same initial states (from scratch or save WAVECAR before) and repeat the calculation with different NSWs using LWAVE=.TRUE.. The calculation with each NSW should hold the WAVECAR for the last ionic step. This way you can for example have 10 calculations with NSW=1,2,3...10, and you would have the WAVECAR for each ionic step of a calculation with 10 ionic steps. This is of course quite time consuming because the same calculation has to be repeated every time adding an additional ionic step. You should also note that if you run on multiple CPU cores the results this way would not give exactly the same as if you run one calculation with the maximum value of NSW due to the randomness in the order of summation in parallel runs.
You can do the same for the electronic steps but only in the first ionic step using NELM.