Contact time duration

Interaction::iterMadeReal will probably help.
Tracking death of the contact is more difficult. You may have to hack
the collider to make it dump deletion data, or write a relatively
complex python script that compares lists of interactions to see if some
of them disappear...

If you know the current number of contact and their lifetimes with
iterMadeReal, isn't there a logical way to deduce the statistics of
death-times?...

Bruno

On 18 May 2012, at 14:15, Chareyre wrote:

> Your question #197576 on Yade changed:
> https://answers.launchpad.net/yade/+question/197576
>
> Status: Open => Answered
>
> Chareyre proposed the following answer:
> Interaction::iterMadeReal will probably help.
Right, I think that can help to track the moment at which the interaction is created.

> Tracking death of the contact is more difficult. You may have to hack
> the collider to make it dump deletion data, or write a relatively
> complex python script that compares lists of interactions to see if some
> of them disappear...
Maybe it could be easily done inside the contact law? In fact, it might be hard to do that in python now that I think more about it.

>
> If you know the current number of contact and their lifetimes with
> iterMadeReal, isn't there a logical way to deduce the statistics of
> death-times?...

>
> Bruno
>
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This question was expired because it remained in the 'Open' state without activity for the last 15 days.

Hi Bruno,

As for this question, I was thinking to something like

if (uN<0) {
phys->contact_time=(scene->iter-contact->iterMadeReal)*scene->dt; //
contact time duration
scene->interactions->requestErase(contact->getId1(),contact->getId2());
}

I tried but the problem is that at the next iteration the contact gets
deleted and so I am not on time to record the value i.phys.contact_time.

Now, how do I output those numbers directly to an output file from Yade
c++ code? Is there any example in Yade I can look at? It is also a
general question which would be good to know.

Or I could create a list from a template where I keep the information of
initial/final/total contact time for each contact. How to do that in
Yade? Any example in the code?

Thanks for help!
Chiara

On 03/06/12 09:22, Launchpad Janitor wrote:
> Question #197576 on Yade changed:
> https://answers.launchpad.net/yade/+question/197576
>
> Status: Open => Expired
>
> Launchpad Janitor expired the question:
> This question was expired because it remained in the 'Open' state
> without activity for the last 15 days.
>

>phys->contact_time=(scene->iter-contact->iterMadeReal)*scene->dt;

Be carefull, dt can change if you use a timeStepper, I guess you figured that. So you need to fix dt in this case...

>Now, how do I output those numbers directly to an output file from Yade c++ code?

grep "ofstream" in the source code.

Hi Chiara,

please, have a look at this code. Maybe, it will be helpful.
https://github.com/yade/trunk/blob/master/pkg/dem/ForceTorqueRecorder.cpp#L13

Anton