The CASINO forum

Katharina,

I am unable to reproduce this bug in a simple test with the current version (v2.13.614) of CASINO. May I ask:

(a) which version of CASINO are you using in this case?

(b) could you post your input files / do you have a minimal working example which displays the bug?

Regards,
Ryan.

Katharina, Just to clarify, which VMC runs are leading to different correlation times? Is it the correlation times in the emin config-generation VMC run and the correlation time in the varmin_linjas final VMC run that you are comparing? In this case, there's surely a bug (you are using identical wav...

Vladimir, I think you are correct, however, it is nearly always the case that after an initial parameter optimisation (varmin/madmin) one would want to (before DMC) run a few cycles of Emin. I'm not suggesting to use either variance minimisation or mad minimisation when forming your final DMC trial ...

Vladimir, The quoted variance-related argument is true. However, DMC doesn't just begin and end, sampling the equilibrium distribution the whole time. That's why we have an equilibration period. If one uses an energy minimised wave function, it makes sense that this equilibration period is shorter (...

Dear Vladimir, The final index for alpha, and the second-to-last indices for beta and gamma are the "spin-pair-type" indices. If one allows for a spin dependence of the corresponding terms in the Jastrow exponent, then these indices may differ from each other (e.g. if you make the simple c...

Dear s.nasiri,

I'm sorry but that's the only idea I had! I dont currently have time to dig around myself .

Good luck! - Ryan.

Dear s.nasiri, I am not familiar with the "getdet" script, although I have experienced what you are describing with a perl script before. Often this error is the cause of improper end-line character formatting. Try running "dos2unix" on the script and see if you still have the er...

Dear Ivan, If you have compiled v2.12 of CASINO with gfortran, then be careful with your AE DMC calculations - we recently noticed a problem with the default gfortran compiler flags that leads to additional noise (and sometimes disastrous breaking of the variational principle) in AE DMC. This is fix...

Ivan, I would say that your time steps seem reasonable then. Barring any malfunctions the only advice I can give is to accumulate more statistics. 800k steps for an AE dmc calculation is not massively big. How many equilibration steps have you performed? Are you running with an up-to-date version of...

Ivan,

Could you give more information about your specific system? Most importantly, are you using pseudo potentials or are you performing all electron calculations?

Thanks, Ryan.