Thanks.

By <scale>, do you mean post_update_options.scale  not the 
post_update_options.pressure.simple.scale?

Should the post_update_options.pressure.simple.scale  should always be some 
small number like 0.0003 in the SPC/E ibi_pressure example?

While the post_update_options.scale should be 1 for a single interaction, 
or the sum of these should sum to 1 for multiple interactions?

Thanks again.

Josh

On Thursday, February 16, 2017 at 4:05:26 PM UTC-5, Christoph Junghans 
wrote:

> 2017-02-16 13:51 GMT-07:00 Joshua Moore <[email protected] <javascript:>>: 
> > Good discussion.  I understand the pressure correction a little better 
> now. 
> > 
> > I was doing 
> > 
> > A-A 
> > 
> > <do>1 0 0</do> 
> > 
> > B-B 
> > 
> > <do>0 1 0</do> 
> > 
> > A-B 
> > 
> > <do>0 0 1</do> 
> > 
> > And applying the total pressure to each interaction.  So that would work 
> > with 3 interactions?  If you had 4, could you do 
> > 
> > <do>0 0 0 1</do>  ?? 
> Yes! 
>
> > 
> > Or you are saying, you could update them all in the same step, but just 
> > apply a scaling factor so that the total of all scale factors is 1? 
> The other option is to do <do>1</do> for all interaction, meaning do 
> pressure correction every step. 
> And adjust the scaling factor (i.e. <scale>XXX</scale>) to something 
> smaller. 
>
> Christoph 
> > 
> > Thanks. 
> > 
> > Josh 
> > 
> > On Thursday, February 16, 2017 at 3:43:43 PM UTC-5, Christoph Junghans 
> > wrote: 
> >> 
> >> 2017-02-16 13:29 GMT-07:00 Sikandar Mashayak <[email protected]>: 
> >> > 
> >> > 
> >> > On Thu, Feb 16, 2017 at 2:23 PM, Christoph Junghans <
> [email protected]> 
> >> > wrote: 
> >> >> 
> >> >> 2017-02-16 13:05 GMT-07:00 Joshua Moore <[email protected]>: 
> >> >> > Hi Christoph, 
> >> >> > 
> >> >> > Thanks again.  I think I've implemented all your suggestions 
> except 
> >> >> > for 
> >> >> > 
> >> >> > "If you want to allow a pressure file per-interaction add 
> >> >> > <pressure_file> to <lammps> block inside the <non-bonded> block 
> >> >> > and use 
> >> >> > p_file="$(csg_get_interaction_property 
> inverse.lammps.pressure_file)" 
> >> >> > " 
> >> >> > 
> >> >> > I will have to think about that one.  I think just a single 
> pressure 
> >> >> > makes 
> >> >> > sense, no? 
> >> >> Multi-component pressure correction is bit tricky. You would need 
> the 
> >> >> contribution from each individual interaction. 
> >> >> The standard version of Gromacs cannot calculated that and hence we 
> >> >> just use the total pressure. 
> >> > 
> >> > 
> >> > Won't this cause extra counting/corrections to the multiple 
> >> > interactions, 
> >> > i.e., multiple pair potentials will be modified to correct the same 
> >> > pressure 
> >> > resulting in over corrections and hence, error. 
> >> You can use individual scaling factors (e.g. 0.25,0.5, 0.25) to 
> >> correct for that statically. 
> >> 
> >> > 
> >> > I think, either the pressure correction should be added to only one 
> >> > interaction for a given iteration or use partial pressures 
> corresponding 
> >> > to 
> >> > each interaction to compute the pressure corrections. 
> >> I usually prefer the former approach, too, but it doesn't work very 
> >> well if one of the two species is underrepresented and hence you 
> >> correct for a pressure, which mostly comes from a different 
> >> interaction. 
> >> 
> >> Christoph 
> >> > 
> >> > Best, 
> >> > Sikandar 
> >> > 
> >> >> 
> >> >> You could also do a version where it fails back to total pressure, 
> >> >> something like: 
> >> >>  p_file="$(csg_get_interaction_property --allow-empty 
> >> >> inverse.lammps.pressure_file)" 
> >> >> [[ -z ${p_file] ]] && p_file="$(csg_get_interaction_property 
> >> >> inverse.lammps.pressure_file)" 
> >> >> 
> >> >> One more thing, please add documentation for new xml options to 
> >> >> share/xml/csg_defaults.xml. 
> >> >> 
> >> >> > 
> >> >> > The other issue was a typo.  Thanks for suggesting that.  I had 
> >> >> > <post_update></post_update> in twice, the second time, with 
> nothing 
> >> >> > in 
> >> >> > it, 
> >> >> > so think it overrides the previous block.  Seems to be updating 
> now. 
> >> >> Good that you found it, I have seen that problem before! 
> >> >> 
> >> >> Christoph 
> >> >> > 
> >> >> > I will do a pull request later today after a bit more testing, but 
> I 
> >> >> > think 
> >> >> > it's ok now. 
> >> >> > 
> >> >> > Thanks. 
> >> >> > 
> >> >> > Josh 
> >> >> > 
> >> >> > 
> >> >> > 
> >> >> > On Thursday, February 16, 2017 at 1:46:29 PM UTC-5, Christoph 
> >> >> > Junghans 
> >> >> > wrote: 
> >> >> >> 
> >> >> >> 2017-02-16 10:20 GMT-07:00 Joshua Moore <[email protected]>: 
> >> >> >> > Hi Christoph, 
> >> >> >> > 
> >> >> >> > I think I have it basically working now, but I might be having 
> a 
> >> >> >> > few 
> >> >> >> > issues. 
> >> >> >> > Here is what I did 
> >> >> >> > 
> >> >> >> > 1) I created a calc_pressure_lammps.sh file as you suggested. 
>  It 
> >> >> >> > is 
> >> >> >> > attached, but it is basically just calculating the average of a 
> >> >> >> > column 
> >> >> >> > of 
> >> >> >> > pressures I've outputted from LAMMPS using awk and assigning 
> this 
> >> >> >> > to 
> >> >> >> > the 
> >> >> >> > p_new variable.  I have hard coded the name of the lammps file 
> >> >> >> > (called 
> >> >> >> > lammps.pressure), as I wasn't sure how this could be read into 
> the 
> >> >> >> > script. 
> >> >> >> Nice, it looks very good! 
> >> >> >> 
> >> >> >> I would add an option to xml file in lammps block, e.g. 
> >> >> >> <cg> 
> >> >> >>   ... 
> >> >> >>   <inverse> 
> >> >> >>    <lammps> 
> >> >> >>       ... 
> >> >> >>       <traj>traj.dump</traj> 
> >> >> >>       ... 
> >> >> >>       <pressure_file>lammps.pressure</pressure_file> 
> >> >> >>     </lammps> 
> >> >> >>   </inverse> 
> >> >> >> </cg> 
> >> >> >> and then you can read its value inside the script using: 
> >> >> >> p_file="$(csg_get_property cg.inverse.lammps.pressure_file)" 
> >> >> >> If you want to allow a pressure file per-interaction add 
> >> >> >> <pressure_file> to <lammps> block inside the <non-bonded> block 
> >> >> >> and use 
> >> >> >> p_file="$(csg_get_interaction_property 
> >> >> >> inverse.lammps.pressure_file)" 
> >> >> >> 
> >> >> >> In addition, I would check if the pressure file exists before 
> >> >> >> invoking 
> >> >> >> awk: 
> >> >> >> [[ -f ${p_file} ]] || die "${0##*/}: pressure file '${p_file}" 
> >> >> >> doesn't 
> >> >> >> exist" 
> >> >> >> and check that awk actually ran correctly: 
> >> >> >> p_now=$(...) || die "${0##*/}: pressure averaging failed" 
> >> >> >> 
> >> >> >> (Note "${0##*/}" is just the name of the script) 
> >> >> >> > 
> >> >> >> > 2) 
> >> >> >> > Added "pressure lammps calc_pressure_lammps.sh" in csg_table 
> below 
> >> >> >> > "pressure 
> >> >> >> > gromacs calc_pressure_gromacs.sh" 
> >> >> >> > 
> >> >> >> > 3) Commented out in postupd_pressure.sh this line 
> >> >> >> > 
> >> >> >> > #[[ $sim_prog != gromacs ]] && die "${0##*/}: pressure 
> correction 
> >> >> >> > for 
> >> >> >> > ${sim_prog} is not implemented yet!" 
> >> >> >> I would change it to that: 
> >> >> >> [[ $sim_prog != @(gromacs|lammps) ]] && die "${0##*/}: pressure 
> >> >> >> correction for ${sim_prog} is not implemented yet!" 
> >> >> >> so that it only works for lammps and gromacs 
> >> >> >> 
> >> >> >> Can you do a pull request with these changes? 
> >> >> >> Details: 
> >> >> >> 
> >> >> >> 
> >> >> >> <
> https://github.com/votca/csg/wiki/BugFix#for-users-contribute-a-bug-fix> 
> >> >> >> 
> >> >> >> > 
> >> >> >> > 4) It seems to be running and the pressure appears to be 
> >> >> >> > improving. 
> >> >> >> > I 
> >> >> >> > have 
> >> >> >> > 3 bead types for the hexane example, and 3 interactions, A-A, 
> B-B, 
> >> >> >> > and 
> >> >> >> > A-B. 
> >> >> >> > VOTCA is only writing a A-A.pressure and a A-B.pressure file. 
>  It 
> >> >> >> > doesn't 
> >> >> >> > seem to be writing a B-B.pressure file, so I'm not sure if it 
> is 
> >> >> >> > updating 
> >> >> >> > the B-B interaction?? 
> >> >> >> That is a bit more tricky. I am guessing there is a typo in the 
> xml 
> >> >> >> file, but I will look more in detail later. 
> >> >> >> I would look for the output and check: 
> >> >> >> - if the IBI update itself done for A-B 
> >> >> >> - if pressure is listed as a Post-update for the A-B interaction 
> >> >> >> - check inverse.log if calc_pressure_lammps.sh is called for A-B 
> at 
> >> >> >> all. 
> >> >> >> 
> >> >> >> Christoph 
> >> >> >> > 
> >> >> >> > I am attaching the settings.xml file where I am calling for the 
> >> >> >> > pressure 
> >> >> >> > correction.  Can you take a look to see if it is defined 
> correctly 
> >> >> >> > there? 
> >> >> >> > 
> >> >> >> > In the *tar.gz I am attaching my current version of the ibi for 
> >> >> >> > LAMMPS 
> >> >> >> > with 
> >> >> >> > real units and pressure correction. 
> >> >> >> > 
> >> >> >> > Thanks again for all your help. 
> >> >> >> > 
> >> >> >> > Josh 
> >> >> >> > 
> >> >> >> > 
> >> >> >> > On Wednesday, February 15, 2017 at 11:05:47 AM UTC-5, Joshua 
> Moore 
> >> >> >> > wrote: 
> >> >> >> >> 
> >> >> >> >> Hello, 
> >> >> >> >> 
> >> >> >> >> It appears the pressure correction for LAMMPS is not 
> implemented. 
> >> >> >> >> 
> >> >> >> >> I saw this post by Frank 
> >> >> >> >> 
> >> >> >> >> https://groups.google.com/d/msg/votca/Jxsdz6v9QKw/OUVfYan8CwAJ 
> >> >> >> >> 
> >> >> >> >> It seems like in order to make it work, you would just have to 
> >> >> >> >> feed 
> >> >> >> >> in 
> >> >> >> >> the 
> >> >> >> >> pressure from LAMMPS. 
> >> >> >> >> 
> >> >> >> >> What would be required for this? 
> >> >> >> >> 
> >> >> >> >> Could I have LAMMPS output an average pressure, and then this 
> >> >> >> >> could 
> >> >> >> >> be 
> >> >> >> >> fed 
> >> >> >> >> into pressure_cor_simple.pl as my $p_now=$ARGV[0]; ?? 
> >> >> >> >> 
> >> >> >> >> How does Gromacs do it?  Does Gromacs calculate an average 
> >> >> >> >> pressure 
> >> >> >> >> and 
> >> >> >> >> that is fed in as $ARGV[0] into the perl script? 
> >> >> >> >> 
> >> >> >> >> Thanks. 
> >> >> >> >> 
> >> >> >> >> Josh 
> >> >> >> > 
> >> >> >> > -- 
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> >> >> >> > For more options, visit https://groups.google.com/d/optout. 
> >> >> >> 
> >> >> >> 
> >> >> >> 
> >> >> >> -- 
> >> >> >> Christoph Junghans 
> >> >> >> Web: http://www.compphys.de 
> >> >> > 
> >> >> > -- 
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> >> >> 
> >> >> 
> >> >> 
> >> >> -- 
> >> >> Christoph Junghans 
> >> >> Web: http://www.compphys.de 
> >> >> 
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> >> > 
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> >> 
> >> -- 
> >> Christoph Junghans 
> >> Web: http://www.compphys.de 
> > 
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>
>
> -- 
> Christoph Junghans 
> Web: http://www.compphys.de 
>

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