My Community

In the attached calculation below, we ran a VASP 6.5.0 calculation where we set the value of KSPACING in the INCAR and did not include a KPOINTS file. The calculation runs to completion, but the stdout includes the warning below. This is quite odd because the KSPACING flag is seemingly recognized and is the currently recommended approach according to the manual.

Concerningly, the VASP documentation (wiki/index.php/Terminal_output) includes this specific warning with the corresponding text: "If the problem is considered less severe, VASP will continue with the execution, but can display a warning. E.g. if the KPOINTS file is missing and KSPACING is not set in the INCAR file, VASP will execute with a default, quite coarse, mesh." This documentation is perplexing to me because it is suggesting that this warning should only appear if KSPACING is not set in the INCAR, but we do have KSPACING set in our INCAR.

This situation leaves us hesitant to trust the results of the VASP calculation without further guidance from the VASP team.

 LDA part: xc-table for (None), standard interpolation
 -----------------------------------------------------------------------------
|                                                                             |
|           W    W    AA    RRRRR   N    N  II  N    N   GGGG   !!!           |
|           W    W   A  A   R    R  NN   N  II  NN   N  G    G  !!!           |
|           W    W  A    A  R    R  N N  N  II  N N  N  G       !!!           |
|           W WW W  AAAAAA  RRRRR   N  N N  II  N  N N  G  GGG   !            |
|           WW  WW  A    A  R   R   N   NN  II  N   NN  G    G                |
|           W    W  A    A  R    R  N    N  II  N    N   GGGG   !!!           |
|                                                                             |
|     The requested file  could not be found or opened for reading            |
|     k-point information. Automatic k-point generation is used as a          |
|     fallback, which may lead to unwanted results.                           |
|                                                                             |
 -----------------------------------------------------------------------------

Hi,

Indeed, this warning is printed although KSPACING is specified. This is misleading and I will suggest to change this.

Your calculation should be fine. You can find the k-mesh specified as n1xn2xn3 in OUTCAR next to "generate k-points for:".

Thanks! That makes sense.

It would indeed be good to have this warning suppressed in the future to prevent any confusion with the scenario where the user does not include a KPOINTS file or a KSPACING parameter in the INCAR.