compile VASP ncl AND gam

Questions regarding the compilation of VASP on various platforms: hardware, compilers and libraries, etc.

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fgoeltl2
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compile VASP ncl AND gam

#1 Post by fgoeltl2 » Fri Jul 16, 2021 9:20 pm

I am currently calculating spin orbit coupling (SOC) calculations for a system where only one gamma point is required.
SOC calculations require the use of the vasp_ncl executable, which is not optimized for gamma-only calculations. I was wondering whether it is possible to compile a vasp_gam_ncl version of VASP.

Thank you for your help!

henrique_miranda
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Re: compile VASP ncl AND gam

#2 Post by henrique_miranda » Mon Jul 19, 2021 6:57 am

There is no vasp_ncl and gam version.
In the vasp_gam the charge can be treated as a real quantity.
For non-collinear spin calculations vasp_ncl, the charge density is treated as a complex quantity.
This is to treat the up-up, up-down, and down-down components of the charge density from which the magnetization can be computed.

As such there can be no gamma-only version for a non-collinear spin.
Or to put it more precisely: the optimizations that can be used for the gamma only version (treat the charge as real and doing complex-to-real FFT) cannot be used in the case of non-collinear spin.

fgoeltl2
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Re: compile VASP ncl AND gam

#3 Post by fgoeltl2 » Tue Jul 20, 2021 7:23 pm

Thank you for the clarification!

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