WAVRCAR file controlled by some settings and modifications.

[hszhao.cn@gmail.com]

I noticed the following description here:

1. Please do NOT set ISYM tag in INCAR (Default ISYM=2).
2. For SOC calculations, please set the MAGMOM tag explicitly in INCAR (for example, MAGMOM=900*0). The default values of MAGMOM could cause the SYMMETRY error when using IRVSP.
3. For VASP6.x, please modify the line "CALL SET_SPINROT_WRAPPER(LATT_CUR%B(1,1),-1)" in mkpoints.F to "CALL SET_SPINROT_WRAPPER(LATT_CUR%B(1,1),IU6)" and recompile VASP before using IRVSP.

I'm not sure if you have any understanding of the corresponding impact of the above-mentioned settings and modifications on the generated WAVRCAR file in a specific calculation.

See here for the related discussion.

Regards,
Zhao

[alexey.tal]

Dear Zhao,

We usually don't provide support with problems concerning a third party software.

I assume that your question is about the third item.
Changing the output unit from -1 to IU6 in this routine should enable the code to write out the information about symmetry operations into stdout and should not have an impact on the calculated wave functions.

[hszhao.cn@gmail.com]

Dear alexey.tal,

Changing the output unit from -1 to IU6 in this routine should enable the code to write out the information about symmetry operations into stdout and should not have an impact on the calculated wave functions.

If I use the default setting, aka, -1, then where should I extract these symmetry operations, OUTCAR, vasprun.xml, or some other files?

[alexey.tal]

If the output unit is set to -1, the symmetry operations are not printed anywhere.

[hszhao.cn@gmail.com]

If the output unit is set to -1, the symmetry operations are not printed anywhere.

1. I have checked the source code of several versions of VASP as follows:

Code: Select all

$ ug 'CALL SET_SPINROT_WRAPPER\(LATT_CUR%B\(1,1\)'
vasp_6_2_1/vasp.6.2.1/src/mkpoints.F:        CALL SET_SPINROT_WRAPPER(LATT_CUR%B(1,1),-1)
vasp_6_2_0/vasp.6.2.0/src/mkpoints.F:        CALL SET_SPINROT_WRAPPER(LATT_CUR%B(1,1),-1)
vasp_6_1_0_patched/vasp.6.1.0_patched/src/mkpoints.F:        CALL SET_SPINROT_WRAPPER(LATT_CUR%B(1,1),IU6)
vasp_5_4_4_pl2/vasp.5.4.4.pl2/src/mkpoints.F:      CALL SET_SPINROT_WRAPPER(LATT_CUR%B(1,1),IU6)
vasp_6_1_2_patched/vasp.6.1.2_patched/src/mkpoints.F:        CALL SET_SPINROT_WRAPPER(LATT_CUR%B(1,1),IU6)

So, it seems that -1 is set as the default value in VASP.6.2.x.

2. BTW, how should I set this value if I want symmetric operations to be written to a separate file?

[hszhao.cn@gmail.com]

Based on the blog here and the VASP documentation, it seems that even the output unit is set to -1, the space group operators of the system still can be obtained as follows:

1. Use spglib or pymatgen as suggested here.
2. Use phonopy as follows:

Code: Select all

$ pip install phonopy
$ phonopy --symmetry --tolerance 1e-5 -c POSCAR

Regards,
Zhao

[alexey.tal]

1. I have checked the source code of several versions of VASP as follows:

Yes, this output has been deactivated at some point.

2. BTW, how should I set this value if I want symmetric operations to be written to a separate file?

Actually, if you set the unit to IU6, the space group operators will be written into the OUTCAR file. If you want to write this information into some other file you need to open this file to a unit identifier and pass the corresponding unit to this routine.