The CASINO forum

(all this to say, in this case, I think we might also want to scrutinise the "exact" result as well as we do the DMC result)

Pablo, That's right - however, this value was pieced together from various other places. Some portions of it (vibrational zero point energy, scalar relativistic corrections) are from different theoretical calculations (which presumably have some uncertainties) and one portion of it (the atomisation ...

Vladimir, Thanks for your reply. I'm having a hard time chasing up what exactly has gone into the "exact energy" quoted in the earlier referenced PRE. For example, can you find where the experimental atomization energy of N_2 used to form the electronic ground state energy actually came fr...

Vladimir, I'm not sure what you are asking here. You're ground state energy is: -109.542(1) a.u., whilst the exact value (from Ref. 38 of the quoted PRE article) is -109.5421 a.u. These two are consistent with each other (at the level of statistical significance you are working), and your VMC energy...

Katharina, Ahhhhh! That (a) makes sense and is (b) obviously bad! Removing that pair of if statements should be safe for now. Perhaps in the long-term that block of code should be protected from re-executing, maybe by wrapping it in a conditional which is satisfied only for the first opt. cycle? Per...

Katharina, I have looked a little bit for those kind of statements, however, I think the problem is one specifically affecting the first vmc run when the runtype is 'vmc_opt'. Grepping about for "if" statements involving opt_cycle didn't lead me to anything that seems relevant, though... I...

Katharina,

I think you are correct. I'll make these changes and run my tests. I had spotted the oddity in line 661 of monte_carlo.f90 last night, intending to investigate further today. Unfortunately I haven't had time, but happily you seem to have done this detective work already.

Regards,
Ryan.

Katharina, I don't think it should affect the calculations, however, that would assume no bugs. In my tests, if I manually set vmc_decorr_period to 3 (i.e. to the same as corper_default_vmc), and I repeat the tests from scratch, I find that correlation times agree (within uncertainties).... Regards,...

Katharina, Yes, I can reproduce the issue. Moreover, it doesn't seem specifically dependant on using emin in the second stage. Identical (disagreeing with the output of the varmin_linjas final VMC run) correlation times are found regardless of the new opt_method. Even if the new opt_method is varmin...

Issue also affects AE calculations...