On Wed, Oct 17, 2018 at 6:41 AM changseo park <[email protected]> wrote: > > OK, the more RDF and averaging them will not help. > > About my system, PNIPAM in water, I'm working on CG parameterization for 280K > state which is Coil state based on All atom results( LOPLS + TIP4P/2005) > > I confirmed that the all atom scale PNIPAM has extended structure at 280K and > collapsed structure at 320K statistically (300ns trajectory and check the > histogram of Rg). > > And I need the CG parameter only below the LCST(280K). > > > For non bonded parameter, can I converge the non-bonded parameter one by one?? > > In my system there are 3 bead and total 6 non bonded interaction. > > As trial, I tested only A-A non bonded interaction for IBI and I could get > the potential fully describe the A-A rdf while the IBI for total 6 non bonded > convergence I couldn't. Can I use this as AA non bonded potential?? > > I think the potential AA BB CC AB BC AC should be independent? Correct? > > Although AB BC AC is dependent on AA BB CC, I think AA BB CC potential should > be independent > > actually, I saw the query that the nonbonded interaction is dependent, but > there was no exact explanation > > Plz attach reference or explain precisely about the reason. All your questions are very system specific and not really related to VOTCA itself, so sorry I am not the expert for PNIPAM nor am I a personal tutor, you will have to figure these answers out by yourself. If you need more information about coarse-graining of PNIPAM I would advise you to contact the authors of J. Phys. Chem. B 2018, 122, 1516−1524.
Christoph > > Always thanks to answer my question. > > > > 2018년 10월 17일 수요일 오전 2시 4분 35초 UTC+9, Christoph Junghans 님의 말: >> >> On Tue, Oct 16, 2018 at 12:57 AM changseo park <[email protected]> wrote: >> > >> > After getting sum advice and searching several queries, I did IBI for >> > non-bonded, but still I couldn't get the converged non bonded potential >> > >> > My system composed of one 30m PNIPAM chain in dilute water. the polymer >> > chain composed of 3 bead per monomer so total 90 beads. >> > >> > Since the PNIPAM has hydrophilic and hydrophobic part, the conformation of >> > polymer chain is changing, extended to collapsed. So the rdf has broad and >> > insignificant peak. >> > >> > I got the rdf from NPT 300ns atomistic simulation as target and the IBI >> > process continues in NVT with sd for 10ns per iteration. >> > >> > I used post update option smooth (with iteration 3) and scale (0.1) and I >> > also used do_potential options >> > >> > for bonded potential, I used the results of Boltzmann inversion potential. >> > >> > the attached file shows the target and new rdf for the system at step_11 >> > and step_30 >> > >> > I'm following the method almost same as this paper with different materials >> > <J. Phys. Chem. B 2018, 122, 1516−1524> >> > >> > the convergence of nonbonded interaction is quite good for this system, >> > single PAM in water. >> > >> > The cause for divergence is, I guess, the quality of RDF. >> > >> > I wonder the convergence problem could be solved with better RDF, by doing >> > another 5set of atomistic simulation with 300ns and getting the rdf from >> > average value >> >> I don't think that will help, coarse-graining for a system with >> different phases, like PNIPAM with open and collapsed, is just hard. >> You might need to develop different coarse-grained potential for each >> phase. >> >> Christoph >> > >> > Thanks in advance >> > >> > >> > >> > >> > 2018년 10월 6일 토요일 오전 1시 39분 53초 UTC+9, Christoph Junghans 님의 말: >> >> >> >> On Fri, Oct 5, 2018 at 7:11 AM changseo park <[email protected]> wrote: >> >> > >> >> > >> >> > Thanks for quick answer!! >> >> > >> >> > Okay, the main criteria for convergence is to compare the distribution >> >> > function one by one with target function >> >> > >> >> > In my case, the Convergence sum is start from 15000 and after step 2, >> >> > it varies from 3000~5000 in every step until more than 300 step >> >> > >> >> > when I compared the distribution function, the votca fits the specific >> >> > peak on the target and switch the specific peaks to others again and >> >> > again. is it normal process for votca? >> >> >> >> I am not 100% sure what you mean but it sounds to me like the IBI is >> >> overshooting, so you should try to scale the update with the postupd >> >> scale option. >> >> > >> >> > and, The peak location is similar but the y-value has absolute >> >> > difference comparing to the target, is it OK?? >> >> > >> >> > >> >> > In addtion, I wonder the votca has the potential fixed options which >> >> > means that, >> >> > >> >> > Q. If the A-A rdf shows good convergence comparing to the target >> >> > distribution, then can I fix the A-A non bonded CG parameter and >> >> > continue the iteration for other non bonded interaction? (A-B, A-C >> >> > ...etc)?? >> >> There is no automatic way to do that. >> >> >> >> > >> >> > Since the iteration could be faster when we start from simple >> >> > parameterization to complicated parameterization, is there any tips or >> >> > advice for non bonded IBI instead of iteration for 6 nonbonded >> >> > parameter at the same time. >> >> > (for example, <do_potential> options etc....> >> >> Yeah, you can update one potential per iteration step, using >> >> do_potential "1 0 0 0 0 0" for the 1st potential and "0 1 0 0 0 0" for >> >> the 2nd potential and so on. >> >> >> >> Christoph >> >> > >> >> > Anyway, I really thank to develop votca^^ >> >> > >> >> > >> >> > 2018년 10월 5일 금요일 오후 9시 17분 24초 UTC+9, Christoph Junghans 님의 말: >> >> >> >> >> >> On Fri, Oct 5, 2018 at 6:12 AM changseo park <[email protected]> >> >> >> wrote: >> >> >> > >> >> >> > TO. VOTCA users >> >> >> > >> >> >> > Hi, I'm new user for VOTCA. >> >> >> > >> >> >> > I'm researching about one single chain polymer conformation change >> >> >> > in water dilute system. >> >> >> > >> >> >> > I figured out all the errors based on queries on VOTCA and I started >> >> >> > the IBI step. >> >> >> > >> >> >> > For get CG non bonded parameter, I got the bonded interaction from >> >> >> > the csg_boltzmann and converted to the table form. >> >> >> > >> >> >> > There is no problem to do iteration for non-bonded interaction >> >> >> > >> >> >> > However, the convergence sum is quite big for iteration. >> >> >> > >> >> >> > My convergence criteria is 0.5, but the usual convergence sum is >> >> >> > about 2000~3000. >> >> >> The convergence value depends on a lot of things, e.g. # of >> >> >> interactions, normalization etc., I would put too much belief in that >> >> >> one number, just look at the RDFs in comparison to the targets and see >> >> >> if they have converged. >> >> >> >> >> >> Christoph >> >> >> > >> >> >> > The attached files is about IBI for 6 RDF, non bonded interaction >> >> >> > (AA, AB, AC, BC, BB, CC) >> >> >> > >> >> >> > Plz give me advice to converge non bonded interaction >> >> >> > >> >> >> > Thanks in advance >> >> >> > >> >> >> > -- >> >> >> > 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 post to this group, send email to [email protected]. >> >> >> > Visit this group at https://groups.google.com/group/votca. >> >> >> > For more options, visit https://groups.google.com/d/optout. >> >> >> >> >> >> >> >> >> >> >> >> -- >> >> >> Christoph Junghans >> >> >> Web: http://www.compphys.de >> >> > >> >> > -- >> >> > 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 post to this group, send email to [email protected]. >> >> > Visit this group at https://groups.google.com/group/votca. >> >> > For more options, visit https://groups.google.com/d/optout. >> >> >> >> >> >> >> >> -- >> >> Christoph Junghans >> >> Web: http://www.compphys.de >> > >> > -- >> > 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 post to this group, send email to [email protected]. >> > Visit this group at https://groups.google.com/group/votca. >> > For more options, visit https://groups.google.com/d/optout. >> >> >> >> -- >> Christoph Junghans >> Web: http://www.compphys.de > > -- > 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 post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/votca. > For more options, visit https://groups.google.com/d/optout. -- Christoph Junghans Web: http://www.compphys.de -- 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 post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/votca. For more options, visit https://groups.google.com/d/optout.
