Hi Cecília, I once encountered similar problems with bonded and non-bonded interactions. See Fig. 9 of this paper <https://pubs.acs.org/doi/10.1021/acs.jctc.2c00665>. In short: The problem was that the potential update of the non-bonded has some influence on the bonded distribution, and vice versa. But the potential update is calculated as if they were independent.
The fix in my case was to update the two interactions alternately using `< do_potential>1 0</do_potential>` for bonded and `<do_potential>0 1</do_potential>` for non-bonded interactions. You could try something similar. Otherwise, is your system liquid? Are there non-bonded interactions that you are optimizing at the same time? Greetings, Marvin On Monday, 24 April 2023 at 16:56:42 UTC+2 Cecília Álvares wrote: > Hey there, > > I am currently trying to derive bonded potentials of a very simple CG > system (containing only one bond type and one angle type) using IBI. > However, I have been failing miserably at doing it: instead of reaching > potentials that are better and better at reproducing the target > distributions for the bond and for the angle, I end up having weider and > weider distributions as I do the iterations. I am posting a plot of the > bond and angle distributions to give a glimpse on the "weirdness". I have > already tried: > (1) providing very refined (small bin size and a lot of bins) target > distributions of excelent quality (meaning not noisy at all) for the bond > and the angle. Similarly, I have also tried using less refined target > distributions (larger bin sizes and less amount of bins). > (2) varied a lot the setup in the settings.xml concerning bin sizes for > the distributions to be built at each iteration from the trajectory file. I > have tried very small bin sizes as well as large bin sizes. > (3) increasing the size of my simulation box hoping that maybe it was all > a problem of not having "enough statistics" to build good distributions at > each iteration within the trajectory file I was collecting from my > simulations. > > None of these things has worked and I think I ran out of ideas of what > could possibly be the cause of the problem. Does anyone have any insights? > > I am also attaching my target distributions (this is the scenario in which > I am feeding target distributions lot of points and smaller bin size) and > the settings.xml file for what is worth it. > > [image: plots.png] > -- Join us on Slack: https://join.slack.com/t/votca/signup --- You received this message because you are subscribed to the Google Groups "votca" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/votca/ff82da6f-64af-4ce2-b3f7-6501a7affaf2n%40googlegroups.com.
