[Feature Request]: Error handler for VASP "KBLOWUP" errors

[knoori]

Problem

It would useful to detect "KBLOWUP" errors (cf. https://www.vasp.at/wiki/index.php/Known_issues), which can occur when IBRION = 6 and ISIF >= 3. These errors can be prevalent in phonon and elastic modulus calculations depending on crystal symmetry. There's no fix yet, however the issue can be circumvented by switching off symmetry (ISYM = 0 works well in my experience), so a dedicated handling of this error is meaningful. The other proposed solution - setting KBLOWUP = F in INCAR - has not worked in my tests.

Proposed Solution

Add an error handler to detect KBLOWUP errors. These manifest in OUTCAR as:

 -----------------------------------------------------------------------------
|                                                                             |
|     EEEEEEE  RRRRRR   RRRRRR   OOOOOOO  RRRRRR      ###     ###     ###     |
|     E        R     R  R     R  O     O  R     R     ###     ###     ###     |
|     E        R     R  R     R  O     O  R     R     ###     ###     ###     |
|     EEEEE    RRRRRR   RRRRRR   O     O  RRRRRR       #       #       #      |
|     E        R   R    R   R    O     O  R   R                               |
|     E        R    R   R    R   O     O  R    R      ###     ###     ###     |
|     EEEEEEE  R     R  R     R  OOOOOOO  R     R     ###     ###     ###     |
|                                                                             |
|     RE_READ_KPOINTS: the new IBZ does not contain all k-points of the       |
|     original IBZ.                                                           |
|                                                                             |
|     ... try setting KBLOWUP=.FALSE.                                         |
|     ... as a last resort: switch off symmetry                               |
|                                                                             |
|       ---->  I REFUSE TO CONTINUE WITH THIS SICK JOB ... BYE!!! <----       |
|                                                                             |
 -----------------------------------------------------------------------------

Alternatives

No response

[Andrew-S-Rosen]

Thanks for reporting. If anyone decides to prepare a ix for this issue, I would recommend it being a two-step fix in the handler:

1. Try KBLOWUP=False
2. Then try ISYM = 0.

We don't know in what cases setting KBLOWUP=False works as advertised, so we should try and adhere to the VASP message by default. Since the error occurs quickly, it should not be a big deal if the handler runs through both options.