Re: [ESPResSo-users] inter forcecap individual

[Peter Košovan]

Hi Roya, regarding your questions:

1. Force capping is always optional. One typically uses it for those interactions where ovelaps at initial state are probable.

2. The part of your script which you posted does not guarantee that you should not get a "bond broken ..." message. This dependes on particle coordinates and potential parameters, which you have not disclosed. Note, however, that you cycle may never terminate. If you do not reach min_dist within first 20 rounds, capradius becomes negative and you are running with full LJ interaction.

Regards,

pete

2014-03-23 13:57 GMT+01:00 roya moghaddasi <address@hidden>:

Hello every body,

As I said before I have a cylinder constraint with 40 polymers of 100 length and 4000 counterion  and 400 salt ions in it.

There are WCA interactions between all the particles with each other and all the particles with the constraint. I want to cap the lj interactions and I have 2 questions:

1. Is it necessary not to cap the LJ interactions between all particles and the cylinder or it is optional?

2. I used the following code for forcecapping and I got the error: bond broken between particles....

inter forcecap individual
for {set i 0} { $act_min_dist < $min_dist } {incr i} {
    set capradius [expr 1.0 - 0.5*$i/10.0]
    for {set k 0} { $k <= $max_part_type } {incr k} {
    for {set j $k} { $j <= $max_part_type } {incr j} {
    inter $k $j lennard-jones $particle_epsilon $particle_sigma $particle_cutoff $particle_shift 0 $capradius
    }
}
    integrate 10000
   
    set act_min_dist [analyze mindist]
   
}

I would appreciate if anyone can help me.

best,

Roya

--

Dr. Peter Košovan

Departmtent of Physical and Macromolecular Chemistry

Faculty of Science, Charles University in Prague, Czech Republic

Katedra fyzikální a makromolekulární chemie

Přírodovědecká fakulta Univerzity Karlovy v Praze

www.natur.cuni.cz/chemistry/fyzchem/
Tel. +420221951290

Fax +420224919752

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