I am just confused cause you suggested the conversion to kcal/mol even though 
my initial trajectory is LAMMPS. I have a lammps trajectory (real units) and I 
want to generate lammps .pot files for lammps (real units). I didn't understand 
why I need to do the conversion.  
Best regards, 
Christianna 

> On 25 Apr 2019, at 4:37 PM, [email protected] wrote:
> 
> No, as I see it and I mentioned, the convert_potential lammps command 
> converts the potential into the correct file format and (as discussed) 
> converts the angular potential from rad to deg (ifthe --no-r2d option is not! 
> set), but it will not convert units. So it always matters what the units of 
> the original simulation have been (kj/mol or kcal/mol) The factor 0.239006 
> converts kj/mol (GROMACS default units) into kcal/mol (LAMMPS units real). 
> .... When converting e.g. the pair potential, you also have to convert then 
> nm (GROMACS default units) into nm (LAMMPS units real) or vice versa or not 
> depending which code you used for the atomistic simulation and which one you 
> will use for the CG simulation.
> 
> Best
> 
> Christoph
> 
> Am Donnerstag, 25. April 2019 15:20:42 UTC+2 schrieb CHRISTINA-ANNA GATSIOU:
> One additional question. In case I use LAMMPS with real units and I am 
> performing IBI do I need to add scaling (0.239006) to my ibi settings.xml. 
> Thanks
> Christianna  
> 
>> On 23 Apr 2019, at 6:23 PM, christoph...@ <>gmail.com <http://gmail.com/> 
>> wrote:
>> 
>> If I see it correctly in 
>> https://github.com/votca/csg/blob/master/share/scripts/inverse/potential_shift.pl#L82
>>  
>> <https://github.com/votca/csg/blob/master/share/scripts/inverse/potential_shift.pl#L82>,
>>  for bonded interactions the shift value is determined as the lowest 
>> potential value which e.g. for a quadratic potential would be the minimum:
>> 
>> for(my $i=0; $i<=$#r; $i++) {
>>     $zero=$dpot[$i] if (($flag[$i] =~ /[i]/) and not defined($zero));
>>     $zero=$dpot[$i] if (($flag[$i] =~ /[i]/) and ($dpot[$i]<$zero));
>> }
>> 
>> However, in this case the lowest potential value is -47041495963199 at 1.5
>> 
>> 
>> 
>> Am Dienstag, 23. April 2019 17:14:35 UTC+2 schrieb Christoph Junghans:
>> On Tue, Apr 23, 2019 at 9:02 AM <[email protected] <>> wrote: 
>> > 
>> > Hi, 
>> > 
>> > as I see it the default --shift option in the table conversion causes the 
>> > problem (it shifts all potential values by the 10^14) factor as you have 
>> > very high forces and thus potential energies at the "left" border of your 
>> > table. 
>> 
>> Thanks, that was a good catch! I am wondering isn't the potential for 
>> angle interactions suppose to shift so that the minimum is at 0? 
>> Code here: 
>> https://github.com/votca/csg/blob/master/share/scripts/inverse/potential_shift.pl#L82
>>  
>> <https://github.com/votca/csg/blob/master/share/scripts/inverse/potential_shift.pl#L82>
>>  
>> 
>> So where does it go wrong? 
>> 
>> Christoph 
>> > 
>> > I tried the following commands and it seems to work: 
>> > 
>> > 
>> > csg_call table integrate A-B-A.force A-B-A.pot 
>> > csg_call table linearop A-B-A.pot A-B-A.pot -1 0 
>> > 
>> > csg_call --ia-type angle --ia-name A-B-A --options 
>> > settings_convert_table_angles.xml convert_potential lammps --no-shift 
>> > --clean A-B-A.pot A-B-A.table 
>> > 
>> > with the settings file I attached. 
>> > 
>> > The --no-shift option prevents the unwanted shifting. 
>> > 
>> > (As I see it, in case you want to run the simulation with lammps you 
>> > should scale your potential file A-B-A.pot before! you call the 
>> > "convert_potential lammps" command as this command outputs the table in 
>> > the right format and converted to degrees, but does not correct for the 
>> > different units in GROMACS and LAMMPS. Though, if you use lammps units 
>> > real (energy kcal/mol, .... )you have to scale the potential values by 
>> > 0.239006 before by e.g. runninh 
>> > 
>> > csg_call table linearop A-B-A.pot A-B-A.pot_scaled 0.239006 0 
>> > 
>> > and then running 
>> > 
>> > csg_call --ia-type angle --ia-name A-B-A --options 
>> > settings_convert_table_angles.xml convert_potential lammps --no-shift 
>> > --clean A-B-A.pot_scaled A-B-A.table 
>> > 
>> > afterwards) 
>> > 
>> > Best 
>> > 
>> > Christoph 
>> > 
>> > 
>> > 
>> > Am Donnerstag, 18. April 2019 16:07:10 UTC+2 schrieb 
>> > [email protected] <>: 
>> >> 
>> >> Hi, 
>> >> 
>> >> I have been trying to integrate forces and convert potential to lammps 
>> >> .pot format. I used all the appropriate script but after the conversion 
>> >> to lammps the potential for angles seem unreasonable. 
>> >> Very high energy values. Something seems to be going wrong with 
>> >> potential_shift.pl <http://potential_shift.pl/>. I would be grateful if 
>> >> you could share your insights on this. 
>> >> 
>> >> Best regards, 
>> >> Christianna 
>> >> 
>> >> ps. The same thing seems to be happening with Gromacs angle potentials. 
>> > 
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>> 
>> 
>> -- 
>> Christoph Junghans 
>> Web: http://www.compphys.de <http://www.compphys.de/> 
>> 
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