Raspa taking more time

[shivanand]

Hello Prof. David Dubbeldam,

I have observed that RASPA is taking more time than our group's MC code (MTK). Basically I'm using RASPA for CFCMC. But for a check, I did GCMC of hexane (using CBMC) in a gas hydrate system using both RASPA and MTK. I have kept the same number of cycles, cutoff, moves, fugacity etc. MTK took 8 hr to finish while RASPA took  120 hr to finish. To recheck with a simple system, NPT simulation of TIP4P water was done and observed the same kind of nature. The same observed for TraPPE Methane too. Could you please suggest me on this?

Thank you,
Shivanand

[David Dubbeldam]

For a comparison between some MC codes (Cassandra, DL Monte, Music, Raspa and Towhee) see:
https://www.tandfonline.com/doi/full/10.1080/08927022.2017.1375492

There is a wide difference in the statistical value of a single MC step, however their computational performance is quite comparable.

RASPA is not optimized for speed, and meant for relatively small system-sizes. The most expensive part is usually the Ewald-summation.