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faq:hfx_eps_warning

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faq:hfx_eps_warning [2020/08/21 10:15] – external edit 127.0.0.1faq:hfx_eps_warning [2023/09/25 15:33] – bsertcan
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 ====== I received a warning message about the Kohn Sham matrix not 100% occupied when doing Hartree-Fock or hybrid calculations, what is going on, and what should I do?  ====== ====== I received a warning message about the Kohn Sham matrix not 100% occupied when doing Hartree-Fock or hybrid calculations, what is going on, and what should I do?  ======
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 +<note important> **Since version 2023.2** The occupancy of the Kohn-Sham matrix depends whether atomic pairs are neighbours. Two atoms are considered neighbours if their basis functions (Gaussians) are overlapping, which is controlled through the ''EPS_PFG_ORB'' keyword. In large cells, the KS matrix can be sparse because atomic pairs can be further apart. Setting the ''MIN_PAIR_LIST_RADIUS'' to -1 makes sure all atomic pairs within the unit cell are considered neighbours, therefore ensuring a full KS matrix. This is considerably more efficient than reducing ''EPS_PFG_ORB'' to unreasonably small numbers. </note> 
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 When you do a calculation that involves the calculation of the Hartree-Fock exchange (e.g. calculations with hybrid functionals, including using the ADMM method), you may occasionally encounter the following warning message (more often if ADMM is used): When you do a calculation that involves the calculation of the Hartree-Fock exchange (e.g. calculations with hybrid functionals, including using the ADMM method), you may occasionally encounter the following warning message (more often if ADMM is used):
faq/hfx_eps_warning.txt · Last modified: 2023/09/26 12:50 by bsertcan