[SOLVED] //edges,dynamic graph, discontinued period of times

[paul]

Hi there,

As I said I am discovering the joy of playing with dynamics.

Ok now my issue is having paralelle edges with different start and end dates.
To make it clear here is a sample :

Code: Select all

<edge source="3369" end="2007-01-22" target="2949" weight="1" start="2007-01-22" id="133">
        <attvalues>
          <attvalue for="0" value="1"/>
        </attvalues>
      </edge>
      <edge source="3369" end="2007-01-20" target="2949" weight="1" start="2007-01-20" id="131">
        <attvalues>
          <attvalue for="0" value="1"/>
        </attvalues>
      </edge>

See two edges with same sources and target but present only on 2007/01/20 and 2007/01/22.

All right I should use an other technic I guess ?
So here is the real question behind this :

How an edge has to be coded in gexf to be present or hidden at different dates which are not a continued period of time ?

Problem comes to the fact that start and end attributes allows only one period of times and not severals.
So no discontinued presence for edges possible becasue of paralell restriction.

Ok but Does the paralell restriction apply on all graph element ?

Can I for instance declare different attribute values for one attribute id with different start and end dates ?
in code that would be :

Code: Select all

<edge source="3369" end="2007-05-30" target="2949" weight="1" start="2007-01-22" id="133">
        <attvalues>
          <attvalue for="0" value="1" start="2007-01-22" end="2007-01-26"/>
          <attvalue for="0" value="2" start="2007-02-14" end="2007-03-19"/>
          <attvalue for="0" value="3" start="2007-04-22" end="2007-05-30"/>
        </attvalues>
 </edge>

And when the attribute isn't set (from 2007-01-27 to 2007-02-13 and from 2007-03-20 to 2007-04-21 in my example) gephi could use default value ?

This is just a proposition.

To sum up my point :
how to make edges definition (presence or attribute value) change through time in non-continued period of time ?

thx for help

Paul

[admin]

Hi, parallel edges are not supported yet in Gephi.

How an edge has to be coded in gexf to be present or hidden at different dates which are not a continued period of time ?

You have to declare two edges. The principle is simple: each element comes into existence, live...and die.

Can I for instance declare different attribute values for one attribute id with different start and end dates ?

That's the good way to to.

And when the attribute isn't set (from 2007-01-27 to 2007-02-13 and from 2007-03-20 to 2007-04-21 in my example) gephi could use default value ?

That's the current behavior. Default value is declared at attribute's declaration.

[paul]

You have to declare two edges. The principle is simple: each element comes into existence, live...and die.

Well that's exactly what you can't do because of parallel edges... Not htat simple when the same links has to be live hten dead then live again etc...

Can I for instance declare different attribute values for one attribute id with different start and end dates ?



That's the good way to to.

Ok cool I go for this solution then.

Thanks

Paul

[jbilcke]

You have to declare two edges. The principle is simple: each element comes into existence, live...and die.

Well that's exactly what you can't do because of parallel edges... Not htat simple when the same links has to be live hten dead then live again etc...

well actually, unless I misunderstood, you should use "slices" for this purpose:

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<edge ... ... ... start="2009-01-01" end=2009-12-31">
    <slices>
            <slice end="2009-03-01"/><!-- only one (the first) slice may contains a single 'end' attribute; 'start' is simply inferred from the parent tag (edge's start), if present. if not, from the graph's start -->     
            <slice start="2009-02-05" end="2009-03-01"/>   
            <slice start="2009-03-05" end="2009-03-10"/><!--all other slices must of course be strictly defined in the time -->   
            <slice start="2009-06-01"/><!-- only one (the last) slice may contains a single 'start' attribute; 'end' is simply inferred from the parent tag (edge's end), if present. if not, from the graph's end -->         
    </slices>
</edge>

[paul]

Interesting.

I can see slices in the dynamic example but where can I find a explanation of this slice concept ?
Is there a gexf official documentation defining all elements and concepts ?

To be sure is a slice :
a subperiod of time of a node or edge time period in which the node or edge is alive
which implies :
if slices are defined a node or edge will not be alive in time perios not covered by slices

am I right ?

If yes it actually does what I needed.

Paul

[admin]

You'll find the theoretical background in this paper:

Skye Bender-deMoll and McFarland, Daniel A. (2006) “The Art and Science of Dynamic Network Visualization.” Journal of Social Structure. Volume 7, Number 2..(draft PDF)

I didn't talk about it, because this feature is not supported yet in Gephi, as this is a very late addition to the file format.

[paul]

Ok thanks for all those information.
I put slices in my todo list but 'll wait a gephi support first.

But as said upper, changing attributes values (weight) in time seems the good way for me.

Thanks for the paper, will read this.

P

[paul]

Ok I hadn't read the primer document which explain all what I was wondering about.
SO I add the link once again here for those you want to know more about dynamic GEXF : http://gexf.net/1.1draft/gexf-11draft-primer.pdf

Paul

[gephi_gold]

@Paul:

Would it be possible for you to post the code you used to write in the attribute data in R?

Thanks,

Sam