Search found 4 matches

by Cyrus_Umrigar
Fri Mar 09, 2018 6:43 am
Forum: Quantum Monte Carlo
Topic: DMC timestep bias asymptotic
Replies: 14
Views: 41659

Re: DMC timestep bias asymptotic

If you look at Fig. 13 of Umrigar, Nightingale, Runge, J. Chem. Phys. 1993, you will see that it is nearly quadratic near tau=0.
I do not know of a theoretical argument for the behaviour of the time-step error.
What is the x-scale on your plots?

Cyrus
by Cyrus_Umrigar
Thu Feb 20, 2014 1:55 pm
Forum: Computational electronic structure
Topic: OpenMP versus Posix/SystemV
Replies: 7
Views: 15222

Re: OpenMP versus Posix/SystemV

Dear Mike and Lucian,

Thank you very much for the information and for your willingness to share your 3 shared memory subroutines!

Cyrus
by Cyrus_Umrigar
Sat Feb 01, 2014 4:24 am
Forum: Computational electronic structure
Topic: OpenMP versus Posix/SystemV
Replies: 7
Views: 15222

Re: OpenMP versus Posix/SystemV

Mike, Thanks very much for your reply! Your solution sounds like magic. I would guess it is a bit harder to do than you indicate, but if it is even remotely as simple to use as you indicate it would save a lot of time. So, yes, I would be very grateful to have permission to use it. Actually my immed...
by Cyrus_Umrigar
Wed Jan 29, 2014 5:20 pm
Forum: Computational electronic structure
Topic: OpenMP versus Posix/SystemV
Replies: 7
Views: 15222

OpenMP versus Posix/SystemV

This is a general question about parallel programming. Suppose you have a large array that is used by every process but never altered during the run. Examples of this are the B-splines file in VMC/DMC or the integrals file in FCIQMC/SQMC. If every process on a node were to have its own copy of this ...