2011/7/16 chemistry <[email protected]>:
> Hi,
>
> In my case i have the similar shape of the RDFs coming from the
> iterations to the reference RDFs. But the RDFs coming from the
> iterations do not converge to the reference RDFs, that's why i want to
> try to change the numerical factor (0<ai<1) during the iterations,
> maybe it will help to reach needed value of the potential. And back to
> my previous question: "how one can change, for example, after third
> iteration the numerical parameter and start fourth iteration with a
> new numerical factor."
We do not support something like this.
It is not hard to implement it, but things like this are better done
by hand anyway.

1.) Do 3 iterations
2.) Change the scale factor
3.) Do more iterations

Cheers,

Christoph



>
> Thanks a lot in advance,
> Sergio.
>
> On Jul 15, 2:49 pm, Dominik Fritz <[email protected]> wrote:
>> Hi Sergio,
>>
>> have you checked, that you treat intramolecular exclusions in a
>> consistent way?
>> When you obtain the reference RDFs, you typically exclude
>> (intramolecular) pairs of beads, which are interacting via bonded
>> interactions.
>> The same exclusions have to be used for the RDFs coming from the
>> iteration steps; otherwise your potentials will most probably diverge.
>>
>> Cheers,
>>
>> Dominik
>>
>> On 07/15/2011 01:52 PM, chemistry wrote:
>>
>> > Hey!
>>
>> > In general i'm trying to reproduce the article ("Coarse-grained
>> > computer simulations of polymer/fullerene bulk heterojunctions for
>> > organic photovoltaic applications", J.Chem.Theory.Comput., Vol.6, No.
>> > 2, 2010) to be familiar with the ibi procedure. With the help of VOTCA
>> > I've got all bonded interaction potentials, but i still have a problem
>> > with getting the non-bonded interaction potentials. I have the same
>> > RDFs like in this article. During the first three iterations CG
>> > potentials going down from the initial guess to the desired value, but
>> > after third-fifth iteration it going up and diverge. The scale
>> > parameter seems to be just change how fast or how slow it will
>> > diverge. Is it something else how one can influence on the
>> > convergency?
>>
>> > Thanks a lot in advance,
>> > Sergio
>>
>> > On Jul 12, 5:28 pm, Christoph Junghans <[email protected]> wrote:
>>
>> >> You forget adding "scale" to the "post_update" list.
>>
>> >> Cheers,
>>
>> >> Christoph
>>
>> >> 2011/7/12 chemistry <[email protected]>:
>>
>> >>> Hey!
>>
>> >>> Can you please explain how exactly I can set and variate numerical
>> >>> factor ai (0<ai<1) for U(n+1) = U(n) + ai*kb*T*ln(P(n)/P(ref)).
>> >>> Because after 10 iteration instead of convergence I have a big
>> >>> divergence. I've specified already simple pressure correction and it
>> >>> works:
>> >>> <cg>
>> >>> ...
>> >>> <inverse>
>> >>>      <p_target>1</p_target>
>> >>>      <post_update>pressure</post_update>
>> >>>      <post_update_options>
>> >>>      <pressure>
>> >>>        <do>0 0 1</do>
>> >>>        <type>simple</type>
>> >>>        <simple>
>> >>>          <scale>0.0003</scale>
>> >>>        </simple>
>> >>>      </pressure>
>> >>>      </post_update_options>
>>
>> >>> Which update script I should use for this purpose and in which section
>> >>> of settings.xml file I need to specify this option?
>>
>> >>> Thanks a lot in advance,
>> >>> Sergio.
>>
>> >>> On Jul 10, 8:12 pm, "Victor Rühle" <[email protected]> wrote:
>>
>> >>>> Use the post update script scale and its corresponding option
>>
>> >>>>http://www.votca.org/Documentation/reference-cginteraction
>> >>>> --
>> >>>> Diese Nachricht wurde von meinem Android-Mobiltelefon mit K-9 Mail 
>> >>>> gesendet.
>>
>> >>>> chemistry <[email protected]> schrieb:
>>
>> >>>> Hello! in U(n+1) = U(n) + ai*kb*T*ln(P(n)/P(ref)) where one can set 
>> >>>> numerical factor ai (0<ai<1). At the moment my calculation is diverges, 
>> >>>> so in general how one can reach better convergency? Kind regards, 
>> >>>> Sergio On Jul 7, 5:03 pm, Christoph Junghans <[email protected]> 
>> >>>> wrote: > 2011/7/7 chemistry <[email protected]>:> Is it possible do 
>> >>>> not use tables_*.xvg and instead of it set the > > parameters for bond, 
>> >>>> angle and dihedral to the topol.top with > > equilibrium bond length, 
>> >>>> angle and force constants. In this case ibi- > > procedure for my 
>> >>>> system works. > > Yes, if the potential can be reasonably approximated 
>> >>>> by a harmonic > form. Just compare the table to k/2*(r-r_0)^2 ! > > > 
>> >>>> And how one can choose the exact simulation time for one iteration for 
>> >>>> > > different systems? > > There is no rule. The iteration has to be 
>> >>>> long enough, so that the > distributions of the interactions, you want 
>> >>>> to iteratively refine, are > sampled reasonable. Too long iterations 
>> >>>> just waste your computer
>> >>>> time > ;-) > I usually do 100 short iterations follow by 50 longer 
>> >>>> ones, but that > is my personal recipe. > > Cheers, > > Christoph > > > 
>> >>>> > > Thanks a lot in advance, > > Sergio > > > On Jul 5, 5:04 pm, Victor 
>> >>>> Ruehle <[email protected]> wrote: > >> Hey, > > >> 1) I recommend to use 
>> >>>> version 1.2. The functionality + arguments of > >> convert_potentials 
>> >>>> have slightly changed. > > >> 2) in the files you sent me, the bad 
>> >>>> sampled regions were not cut and > >> therefore the extrapolate failed 
>> >>>> (zoom in at table_a0.xvg where the > >> extrapolated region at the left 
>> >>>> starts). This will lead to a very > >> strong peak in the force and is 
>> >>>> probably what messes up your run. > >> Please make sure to really cut 
>> >>>> the very rough points at the left and > >> right of bonded potentials. 
>> >>>> This was done in the sed commands i send > >> you. Either adjust the 
>> >>>> number of points there or better skip this > >> command and do it 
>> >>>> manually. > > >> Victor > > >> 2011/7/5 chemistry 
>> >>>> <[email protected]>: > > >> > Hey,> > >> > the format of the 
>> >>>> table_*.xvg which was created after post-processing > >> > looks like 
>> >>>> this: > > >> > table_a1.xvg: > > >> > 0.0000000000e+00   
>> >>>> 8.6955642509e+07 0.0000000000e+00 > >> > 5.0000000000e-02   
>> >>>> 8.6862417509e+07 1.8640000000e+06 > >> > 1.0000000000e-01   
>> >>>> 8.6769242509e+07 1.8630000000e+06 > >> > 1.5000000000e-01   
>> >>>> 8.6676117509e+07 1.8620000000e+06 > >> > 2.0000000000e-01   
>> >>>> 8.6583042509e+07 1.8610000000e+06 > > >> > and yesterday I've created 
>> >>>> the same format of the table like in your > >> > case by myself. I used 
>> >>>> for this C-programing and described the > >> > potential with the help 
>> >>>> of harmonic potential. And now it works well. > > >> > new one 
>> >>>> table_a1.xvg: > > >> > 0.000000 1201.461834 0 > >> > 0.050000 
>> >>>> 1200.343519 0 > >> > 0.100000 1199.225724 0 > >> > 0.150000 1198.108451 
>> >>>> 0 > >> > 0.200000 1196.991698 0 > > >> > In both cases the potentials 
>> >>>> look similar around the minimum. Is it > >> > possible that the GROMACS 
>> >>>> in someway cannot read correctly the > >> >
>>
>> >>>> table_*.xvg? > > >> > Kind regards, > >> > Sergio > > >> > On Jul 4, 
>> >>>> 7:50 pm, Victor Ruehle <[email protected]> wrote: > >> >> Hey, > > >> >> 
>> >>>> can you please attach your table_?.xvg > > >> >> Cheers, > >> >> Victor 
>> >>>> > > >> >> 2011/7/4 chemistry <[email protected]>: > > >> >> > Hey, 
>> >>>> Victor! > > >> >> > With table_b1.xvg and table_a1.xvg from your 
>> >>>> tutorial simulation for > >> >> > propane works well. > >> >> > I'd 
>> >>>> tried to process the potentials for propane myself and after when > >> 
>> >>>> >> > I started the simulations I've got the same mistake like for my > 
>> >>>> >> >> > system: > > >> >> > "Fatal error: > >> >> > A tabulated bond 
>> >>>> interaction table number 1 is out of the table range: > >> >> > r 
>> >>>> 3.157974, between table indices 3157 and 3158, table length 501" > > >> 
>> >>>> >> > Seems that I have some problem with creating the tables_*.xvg > >> 
>> >>>> >> > Can you please check the way of post-processing of the potentials. 
>> >>>> > >> >> > At the beginning I had the same shape of the potential like 
>> >>>> in your > >> >> >
>> >>>> case (I've got it with csg_boltzmann from all-atom MD simulation of > 
>> >>>> >> >> > propane at T=200 K): > > >> >> > bond: > > >> >> > sed -e 
>> >>>> '1,5d' -e 's/$/ i/' AB.pot | tac | sed -e '1,4d' | tac > AB.cut > >> >> 
>> >>>> > csg_call table smooth AB.cut AB.smooth > >> >> > csg_resample --in 
>> >>>> AB.smooth --out AB.refined --grid 0::0.001:0.5 > >> >> > csg_call table 
>> >>>> extrapolate --function quadratic AB.refined AB.pot.cur > >> >> > 
>> >>>> csg_call --options table.xml convert_potential xvg --type bonded > >> 
>> >>>> >> > AB.pot.cur table_b1.xvg > > >> >> > where table.xml: > > >> >> > 
>> >>>> <cg> > >> >> >   <inverse> > >> >> >    <gromacs> > >> >> >     
>> >>>> <pot_max>1e8</pot_max> > >> >> >     <table_end>0.5</table_end> > >> >> 
>> >>>> >     <table_bins>0.002</table_bins> > >> >> >    </gromacs> > >> >> >  
>> >>>>  </inverse> > >> >> > </cg> > > >> >> > angle: > > >> >> > sed -e 's/$/ 
>> >>>> i/' ABA_angle.pot | tac | sed -e '1,2d' | tac  > ABA.cut > >> >> > awk 
>> >>>> '{print $1/3.141592654*180.0,$2,$3,$4}' ABA.cut > ABA.new.cut > >> >> > 
>> >>>> csg_call table
>> >>>> smooth ABA.new.cut ABA.smooth > >> >> > csg_resample --in ABA.smooth 
>> >>>> --out ABA.refined --grid 0::0.05:180 > >> >> > csg_call table 
>> >>>> extrapolate --function quadratic ABA.refined > >> >> > ABA.pot.cur > >> 
>> >>>> >> > csg_call --options table.xml convert_potential xvg --type bonded > 
>> >>>> >> >> > ABA.pot.cur table_a1.xvg > > >> >> > where table.xml: > > >> >> 
>> >>>> > <cg> > >> >> >   <inverse> > >> >> >    <gromacs> > >> >> >     
>> >>>> <pot_max>1e8</pot_max> > >> >> >     <table_end>180</table_end> > >> >> 
>> >>>> >     <table_bins>0.05</table_bins> > >> >> >    </gromacs> > >> >> >   
>> >>>> </inverse> > >> >> > </cg> > > >> >> > In both cases the potentials 
>> >>>> look similar around the minimum, but > >> >> > afterwords they are 
>> >>>> totally different. I wanted to get the same > >> >> > table_*.xvg like 
>> >>>> in your example. > > >> >> > Yours respectfully, > >> >> > Sergio > > 
>> >>>> >> >> > On Jul 1, 11:34 am, Victor Ruehle <[email protected]> wrote: > 
>> >>>> >> >> >> Be aware, if you have a bug in your coarse-grained topology, 
>> >>>> it might > >> >> >>
>> >>>> immediately crash the simulations similar to the problem you > >> >> >> 
>> >>>> described. The csg_map will give a reasonable initial structure, this > 
>> >>>> >> >> >> should do well if your coarse-grained potentials are ok 
>> >>>> (eventually do > >> >> >> a steep before). The topology generation 
>> >>>> (csg_gmxtopol) just provides > >> >> >> a point to start from but will 
>> >>>> always require tuning by hand to put in > >> >> >> correct parameters. 
>> >>>> > > >> >> >> Also verify your mapping by loading atomistic + 
>> >>>> coarse-grained > >> >> >> structures in vmd. > > >> >> >> 2011/7/1 
>> >>>> chemistry <[email protected]>: > > >> >> >> > Sorry, it was a 
>> >>>> problem with the internet and that's why I posted the > >> >> >> > same 
>> >>>> message twice. > > >> >> >> > I'm doing it in the same way how you 
>> >>>> wrote. So, I'll check all stuff > >> >> >> > again and thanks for fast 
>> >>>> answer. > > >> >> >> > Kind regards. > > >> >> >> > On Jul 1, 11:14 am, 
>> >>>> chemistry <[email protected]> wrote: > >> >> >> >> Hello! > > >> >> 
>> >>>> >> >> Seems that I have not a
>> >>>> good initial CG-structure. I've got it with > >> >> >> >> the help of 
>> >>>> csg_map: > > >> >> >> >> $csg_map --top topol.tpr --trj traj.trr --cg 
>> >>>> mappin.xml --out cg.gro > > >> >> >> >> In my mappin.xml file every 
>> >>>> monomer
>>
>> ...
>>
>> read more »
>
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-- 
Dr. Christoph Junghans
Votca Core Developer

Web: http://www.votca.org

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