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Posted: **Sun Nov 03, 2024 1:13 am**

Hi there,

I noticed there are so many "GGA = --" in OUTCARs, as shown below:

werner@x13dai-t:~/Public/hpc/vasp/src$ ug -I -g '*.ref' -- 'GGA.*--' | head
vasp.6.4.3/testsuite/tests/Xe_z/OUTCAR.ref:   GGA     =    --    GGA type
vasp.6.4.3/testsuite/tests/bulk_CoO_wurzite_SOC_PBE0_nosym_RPR/OUTCAR.ref:   GGA     =    --    GGA type
vasp.6.4.3/testsuite/tests/SrVO3_CRPA_weighted/OUTCAR.ref:   GGA     =    --    GGA type
vasp.6.4.3/testsuite/tests/bulk_CoO_wurzite_ISPIN=2_nosym/OUTCAR.ref:   GGA     =    --    GGA type
vasp.6.4.3/testsuite/tests/SiC_ACFDTR/OUTCAR.ref:   GGA     =    --    GGA type
vasp.6.4.3/testsuite/tests/TiO2_PRECFOCK=FAST/OUTCAR.ref:   GGA     =    --    GGA type
vasp.6.4.3/testsuite/tests/SiC_OEP/OUTCAR.DFT.ref:   GGA     =    --    GGA type
vasp.6.4.3/testsuite/tests/SiC_OEP/OUTCAR.AEXXOEP.ref:   GGA     =    --    GGA type
vasp.6.4.3/testsuite/tests/SiC_OEP/OUTCAR.OEP.ref:   GGA     =    --    GGA type
vasp.6.4.3/testsuite/tests/SiC_OEP/OUTCAR.DIAG.ref:   GGA     =    --    GGA type

So, what's the meaning of "GGA = --"?

Regards,
Zhao

Posted: **Sun Nov 03, 2024 8:22 am**

If the GGA tag is not explicitly specified in INCAR, then the functional from the POTCAR (usually PBE) is used. With older VASP versions, this was indicated with "GGA = --" in OUTCAR. Since VASP.6.4.3 this is properly indicated with "GGA = PE".

Posted: **Sun Nov 03, 2024 8:50 am**

Dear fabien_tran1,

I see. Thank you very much.

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The meaning of "GGA = --".

The meaning of "GGA = --".

Re: The meaning of "GGA = --".

Re: The meaning of "GGA = --".