Hi, Assumption is incorrect.
A Gamma-point calculation uses only real numbers. A k-point calculation uses complex numbers. Hence your matrix memory footprint gets doubled. So 2x2 = 4, and then there is *some* overhead with k-points, i.e. the numerics changes a bit since this is also done in complex numbers. So all seems fine to me :) Den fre. 16. aug. 2024 kl. 22.00 skrev Francisco Garcia < [email protected]>: > Dear users, > > > I run a large job with perfect orbital distribution over processors > (exactly 20 orbitals per processor). > > > As you can see in the data appended below, it takes approximately 25 > seconds between SCF steps in the Gamma point run. > > > For 2 k-points however, it takes approximately 125 seconds between SCF > cycles (see below), which is 5 times the Gamma point time. > > > This is confusing me because a 2 k-point job is technically 2 successive > Gamma point jobs, so I was expecting the time between SCF steps to be > around twice that of the Gamma point job. 5 times is way too high and I was > wondering if there's anything I can do to circumvent this problem. > > > Thanks! > > > Gamma point > > Start of run 0.000 > > -------------- end of scf step 36.845 > > -------------- end of scf step 64.071 > > -------------- end of scf step 89.467 > > -------------- end of scf step 115.114 > > -------------- end of scf step 140.442 > > -------------- end of scf step 169.311 > > -------------- end of scf step 197.407 > > -------------- end of scf step 222.953 > > -------------- end of scf step 248.311 > > -------------- end of scf step 273.939 > > -------------- end of scf step 299.205 > > -------------- end of scf step 325.194 > > -------------- end of scf step 350.430 > > -------------- end of scf step 376.049 > > -------------- end of scf step 401.498 > > -------------- end of scf step 427.002 > > > > 2 k-points > > Start of run 0.000 > > -------------- end of scf step 137.140 > > -------------- end of scf step 263.171 > > -------------- end of scf step 388.183 > > -------------- end of scf step 516.512 > > -------------- end of scf step 641.262 > > -------------- end of scf step 765.025 > > -------------- end of scf step 891.643 > > -------------- end of scf step 1016.512 > > -------------- end of scf step 1140.165 > > -------------- end of scf step 1264.910 > > -------------- end of scf step 1388.616 > > -------------- end of scf step 1512.917 > > -------------- end of scf step 1637.145 > > -------------- end of scf step 1761.197 > > -------------- end of scf step 1885.839 > > -------------- end of scf step 2009.728 > > -- > SIESTA is supported by the Spanish Research Agency (AEI) and by the > European H2020 MaX Centre of Excellence > (https://urldefense.com/v3/__http://www.max-centre.eu/__;!!D9dNQwwGXtA!Uv0cJa-gg72cN5j_k95nAXxIVfr8RET835tytviEZiMv4UMA7-bVjS5urrfjmViNK0jfQG-TTiKrtCvDfQ$ > ) > -- Kind regards Nick
-- SIESTA is supported by the Spanish Research Agency (AEI) and by the European H2020 MaX Centre of Excellence (http://www.max-centre.eu/)
