hi everybody,
I am trying to dump pair interactions (both for all particles and those that are placed in a specific region (defined as MSgroup), seperately) via pair/gran/local, when I use two computes for example as
1.compute GranInter MSgroup pair/gran/local pos id force history
2.compute MGranInter all pair/gran/local pos id force history
it says that Pair gran allows only one compute of type pair/local.
when I use just the second compute and use dump/local command with group MSgroup it returns all of the interactions (not only those related to this group). how can I solve it and dump them seperately.
furthermore, I want to know more about history. are the components of this parameter, those of tangential force (fs1,fs2,fs3 in the source code)? as it is mentioned in the doc that "The tangential force also has 2 terms: a shear force and a damping force. The shear force is a "history" effect.... ", so damping is not included. Or I have just misunderstood? if not, how can I extract tangential or normal force without postprocessing or changing the code?
thanks,
mojgan
ckloss | Fri, 04/19/2013 - 15:43
Hi mojgan,
Hi mojgan,
>>when I use just the second compute and use dump/local command with group
>>MSgroup it returns all of the interactions (not only those related to this group).
>>how can I solve it and dump them seperately.
this should actually work - which version of LIGGGHTS are you using?
>>furthermore, I want to know more about history
history for e.g. pair/gran/hertz/history means elongation of the tangential spring
Best
Christoph
Jing Lu | Wed, 05/20/2015 - 04:06
history in compute pair/gran/local
Hi Chris,
You said history here means 'elongation of the tangential spring', so it has the unit of length? How can I properly output the tangential force for each pair?
I'm using gran/hertz/history for pair_style and compute pair/gran/local history to output tangential force, because I thought history in pair/gran/local means the 3 components of tangential force in xyz (i.e. ft1,ft2,ft3). However the results are extremely small.
Thanks,
Jing
mojgan | Fri, 04/19/2013 - 20:48
Hi christoph,
Hi christoph,
I use LIGGGHTS 2.3. I should mention that using "dump custom" for particles in the region work well. but dumping the interactions does not return the specified group properties.
thanks,
mojgan
ckloss | Mon, 04/22/2013 - 09:58
>>I use LIGGGHTS 2.3
>>I use LIGGGHTS 2.3
only the latest'n'greatest version of LIGGGHTS is supported
Cheers
Christoph
mojgan | Fri, 04/26/2013 - 07:09
hi,
hi,
I have upgraded my liggghts, but everything is the same even with LIGGGHTS 2.3.2.
I define:
region MS block 0.02 0.04 0.02 0.04 0.007 0.013 units box
group MSgroup region MS
then:
compute GranInter all pair/gran/local pos id force
and:
dump MSgrain MSgroup custom 10 post6/MSgrain.* id type x y z fx fy fz radius c_ncont
dump MSGraninter MSgroup local 10 post6/MSinter.* c_GranInter[1] c_GranInter[2] c_GranInter[3] c_GranInter[4] c_GranInter[5] c_GranInter[6] c_GranInter[7] c_GranInter[8] c_GranInter[9] c_GranInter[10] c_GranInter[11] c_GranInter[12]
the first dump command works well but the last one contains all of the interactions.
thanks
mojgan
ckloss | Thu, 05/02/2013 - 13:40
Hi mojgan,
Hi mojgan,
you have to use MSgroup for teh compute command. Dump local does not take the group into account, as it dumps local data, not per-atom data
Cheers
Christoph