Hello!

Thanks again for advices. It's helped me a lot.
I have already created all files what I need for CG calculation. But
now I have a problem with a tabulated bond interaction. I've checked
already this problem on the gromacs mailing-list. Unfortunately they
do not have any good advice there how to solve this problem. I would
be very grateful if you can give me some advice how to solve it. I
have next error message:

"Fatal error:
A tabulated bond interaction table number 2 is out of the table range:
r 0.646802, between table indices 646 and 647, table length 501"

Thanks a lot in advance,
Sergio.


On Jun 27, 6:33 pm, Victor Ruehle <[email protected]> wrote:
> Hey,
>
> i also use csg_boltzmann, the tab command (dont forget tab set scale
> bond / tab set scale angle for bond/angles). some of my examples (the
> .pot files are the output of csg_boltzmann):
> bonds:
> cp ../../pot/AB_bond.pot .
> sed -e '1,5d' -e 's/$/ i/' AB_bond.pot | tac | sed -e '1,4d' | tac >
> AB.cut   ; cut bad sampled regions at the boundaries
> csg_call table smooth AB.cut AB.smooth
> csg_resample --in AB.smooth --out AB.refined --grid 0::0.001:0.5
> csg_call table extrapolate --function quadratic AB.refined AB.pot.cur
> csg_call --ia-type bonded --ia-name AB --options ../convert.xml
> convert_potential gromacs
>
> angles:
> cp ../../pot/ABC_angle.pot .
> #sed -e '1,3d' -e 's/$/ i/' ABC_angle.pot | tac | sed -e '1,3d' | tac > 
> ABC.cut
> sed -e 's/$/ i/' ABC_angle.pot | tac | sed -e '1,2d' | tac  > ABC.cut
> csg_call table smooth ABC.cut ABC.smooth
> csg_resample --in ABC.smooth --out ABC.refined --grid 0::0.001:3.141592654
> csg_call table extrapolate --function quadratic --region left
> ABC.refined ABC.refined
> csg_call table extrapolate --function linear --region right
> ABC.refined ABC.refined
> awk '{print $1/3.141592654*180.0,$2}' ABC.refined > ABC.pot.cur
> csg_call --ia-type angle --ia-name ABC --options ../convert.xml
> convert_potential gromacs
>
> convert.xml:
> <cg>
>   <bonded>
>     <name>AB</name>
>     <inverse>
>       <gromacs>
>         <table>../tables/table_b0.xvg</table>
>       </gromacs>
>     </inverse>
>   </bonded>
>   <bonded>
>     <name>BC</name>
>     <inverse>
>       <gromacs>
>         <table>../tables/table_b1.xvg</table>
>       </gromacs>
>     </inverse>
>   </bonded>
>   <angle>
>     <name>ABC</name>
>     <inverse>
>       <gromacs>
>         <table>../tables/table_a0.xvg</table>
>       </gromacs>
>     </inverse>
>   </angle>
>
>   <inverse>
>     <gromacs>
>       <table_end>3.0</table_end>
>       <table_bins>0.002</table_bins>
>       <pot_max>1000000</pot_max>
>     </gromacs>
>   </inverse>
> </cg>
>
> Diheral i currently don't have tabulated one (fitted functional form
> in my case), but should be similar.
>
> Best,
> Victor
>
> 2011/6/27 chemistry <[email protected]>:
>
> > In this case I have to multiply x value (rad) on (180/3.14) and
> > afterwords I can use this distribution function for getting the
> > potential and if it's not zero just simply shift it to zero?
>
> > On Jun 27, 3:20 pm, Christoph Junghans <[email protected]> wrote:
> >> You can shift the minimum to zero, it will not change the simulation
> >> result (except for a energy offset).
> >> In VOTCA 1.2 the shifting is done automatically if you are using
> >> 'csg_call convert_potential gromacs'
>
> >> Notice that for angles csg_boltzmann calculates everything in rad,
> >> while gromacs (xvg files) wants degrees, so double check the scale of
> >> the x values again.
>
> >> Cheers,
>
> >> Christoph
>
> >> 2011/6/27 chemistry <[email protected]>:
>
> >> > I calculated the potential with awk and with csg_boltzmann. It gives
> >> > the same shape of the curves but in the case when I used awk the
> >> > minimum of the potential has negative value. Should I shift the
> >> > minimum of the potential to zero? Does csg_boltzmann do it
> >> > automatically?
>
> >> > Thanks a lot in advance,
> >> > Sergio
>
> >> > On Jun 26, 4:42 pm, Christoph Junghans <[email protected]> wrote:
> >> >> Hi Sergio,
>
> >> >> the potentials have to look similar around the minimum. The region
> >> >> left and right are usually extrapolated and the exact form of the
> >> >> extrapolation does not matter much as the appearance of these values
> >> >> is exponentially suppressed (exp -E/k_bT).
> >> >> Make sure that the area {U_min..U_min+k_b T} is correct.
>
> >> >> Technically what I do to obtain table_b1.xvg is:
> >> >> -calculate the distribution with csg_stat / csg_boltzmann
> >> >> -calculate the potential using awk
> >> >> $ awk -v kbt=NUMBER '{print $1,($1>0)?-kbt*log($2/$1/$1):"nan"}'
> >> >> bond.dist.new > bond.pot.new
> >> >> -take a look at the potential and cut it down to the well-sampled region
> >> >> -convert it to gromacs format (this was reworked in VOTCA 1.2, before
> >> >> the extrapolation had to be done by hand)
> >> >> $ csg_call --options bond.xml --ia-type bonded convert_potential
> >> >> gromacs bond.pot.new2 table_b1.xvg
> >> >> where bond.xml looks like this:
> >> >> <cg>
> >> >>   <inverse>
> >> >>     <program>gromacs</program>
> >> >>     <gromacs>
> >> >>       <pot_max>1e8</pot_max>
> >> >>       <table_end>3</table_end>
> >> >>       <table_bins>0.002</table_bins>
> >> >>     </gromacs>
> >> >>   </inverse>
> >> >> </cg>
>
> >> >> table.xvg is used to calculate the interactions for all pairs, which
> >> >> do not appear in energygrp_table (in the mdp file).
> >> >> If all pairs are covered by energygrp_table combinations you can use
> >> >> any table, but I would use a table filled with zeros.
> >> >> table.xvg can be useful in cases when you want to mix IBI tables with
> >> >> a standard force field, then  table.xvg should be the default 6-12 LJ
> >> >> table ($GMXDATA/gromacs/top/table6-12.xvg)
>
> >> >> Cheers,
>
> >> >> Christoph
>
> >> >> 2011/6/26 chemistry <[email protected]>:
>
> >> >> > Thanks a lot for the previous advices!
>
> >> >> > I have one more question about table_*.xvg. Can you explain please how
> >> >> > exactly did you create all tables for the propane which you used for
> >> >> > the ibi-procedure (table.xvg, table_a1.xvg, table_b1.xvg). I did the
> >> >> > post-processing of the potentials (bond and angle) and I've got the
> >> >> > same shape for the potentials but much more higher value for the y-
> >> >> > axis. The distribution functions and potentials for bond and angle are
> >> >> > the same like in your presentation. Did  I do something wrong or is it
> >> >> > something else what I should know? And which role plays table.xvg in
> >> >> > this case?
>
> >> >> > Thanks a lot in advance,
> >> >> > Sergio.
>
> >> >> > On Jun 23, 11:34 am, Christoph Junghans <[email protected]> wrote:
> >> >> >> Hi Sergio,
>
> >> >> >> 2011/6/22 chemistry <[email protected]>:> Thanks a lot for 
> >> >> >> advice, I checked all again and I found the mistake
> >> >> >> > in my mappin.xml file. I fixed it and now it works well.
> >> >> >> > Is it something important in the calculation of the rdf in the
> >> >> >> > iterations for such a systems?
>
> >> >> >> Usually one don't want to consider pairs of beads, which interact via
> >> >> >> a bonded potential, for the rdf.
> >> >> >> The reason is that the rdf is used to calculate the non-bonded
> >> >> >> interaction and so only the pairs which interact non-bonded should go
> >> >> >> in the rdf.
>
> >> >> >> However in some cases it is useful to calculate the rdf with 
> >> >> >> different
> >> >> >> exclusions than the simulation was performed. (the
> >> >> >> cg.inverse.gromacs.rdf.topol option in the xml setting file, see the
> >> >> >> manual)
>
> >> >> >> Cheers,
>
> >> >> >> Christoph
>
> >> >> >> > Thanks a lot in advance.
> >> >> >> > Sergio
>
> >> >> >> > On Jun 21, 6:02 pm, Victor Ruehle <[email protected]> wrote:
> >> >> >> >> Hmm, are you sure that  all the beads which should be excluded are
> >> >> >> >> part of an angle definition?  If yes, Votca  should exclude them
> >> >> >> >> automatically..
>
> >> >> >> >> I'm doing a very similar thing and it worked for me. Will check
> >> >> >> >> tomorrow whether there might be a new bug.However, third or fourth
> >> >> >> >> nearest neighbors should still be visible, there is no option so 
> >> >> >> >> far
> >> >> >> >> to exclude all beads in the molecule. I could add that if 
> >> >> >> >> necessary.
>
> >> >> >> >> Please verify if the peaks you observe really correspond to second
> >> >> >> >> nearest neighbors, and if  yes whether you have this particular 
> >> >> >> >> angle
> >> >> >> >> defined in the mapping.  Also check csg_dump --excl
>
> >> >> >> >> 2011/6/21 chemistry <[email protected]>:
>
> >> >> >> >> > I'm trying to calculate the target rdf for polymer system with 
> >> >> >> >> > the
> >> >> >> >> > "csg_stat" and also I'm interested to calculate the rdf in the
> >> >> >> >> > iterations:
>
> >> >> >> >> >  csg_stat --top topol.tpr --trj traj.xtc --options settings.xml 
> >> >> >> >> > --cg
> >> >> >> >> > mapping.xml
>
> >> >> >> >> > I have P3HT system. Every monomer divided on the three beads.
> >> >> >> >> > Thiophene ring represented the first bead and hexyl chain 
> >> >> >> >> > divided on
> >> >> >> >> > the two beads - each bead include three carbon atoms.
>
> >> >> >> >> > in the settings.xml file I specified the types of the beads 
> >> >> >> >> > which are
> >> >> >> >> > the same like in the mapping.xml:
>
> >> >> >> >> > .............
> >> >> >> >> >  <non-bonded>
> >> >> >> >> >    <!-- name of the interaction -->
> >> >> >> >> >    <name>P1-P1</name>
> >> >> >> >> >    <!-- types involved in this interaction -->
> >> >> >> >> >    <type1>A</type1>
> >> >> >> >> >    <type2>A</type2>
> >> >> >> >> >    <!-- dimension + grid spacing of tables for calculations -->
> >> >> >> >> >    <min>0</min>
> >> >> >> >> >    <max>1.36</max>
> >> >> >> >> >    <step>0.01</step>
> >> >> >> >> >    <inverse>
> >> >> >> >> >      <!-- target distribution (rdf), just give gromas rdf.xvg 
> >> >> >> >> > -->
> >> >> >> >> >      <target>P1-P1.dist.tgt</target>
> >> >> >> >> >      <!-- update cycles -->
> >> >> >> >> >      <do_potential>1 0 0</do_potential>
> >> >> >> >> >      <!-- additional post processing of dU before added to 
> >> >> >> >> > potential
> >> >> >> >> > -->
> >> >> >> >> >      <post_update></post_update>
> >> >> >> >> >      <!-- additional post processing of U after dU added to 
> >> >> >> >> > potential
> >> >> >> >> > -->
> >> >> >> >> >      <post_add></post_add>
> >> >> >> >> >      <!-- name of the table for gromacs run -->
> >> >> >> >> >      <gromacs>
> >> >> >> >> >        <table>table_P1_P1.xvg</table>
> >> >> >> >> >      </gromacs>
> >> >> >> >> >    </inverse>
> >> >> >> >> >  </non-bonded>
> >> >> >> >> > ...............
>
> >> >> >> >> > ---mapping.xml---:
>
> >> >> >> >> > <cg_molecule>
> >> >> >> >> >  <name>P3HT</name>
> >> >> >> >> >  <ident>Protein_X</ident>
> >> >> >> >> >  <topology>
> >> >> >> >> >    <cg_beads>
> >> >> >> >> >      <cg_bead>
> >> >> >> >> >        <name>S1</name>
> >> >> >> >> >        <type>A</type>
> >> >> >> >> >      
>
> ...
>
> read more »

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