Re: Create graph with multiple links between two nodes from dot file

[Yoann Pigné <yoann.pigne AT gmail.com>]

Hi, 

Short answer : the DOT reader in GraphStream kind of only supports single graphs. 

There is no simple solution to the problem other than a rework of the DOT parser in GS. 

Can I suggest you use a file format where GS can safely handle multigraphs like the DGS :

*********

DGS004

example 2 2

an a

an b 

ae e1 a > b

ae e2 a > b 

*********

File spec  here : https://graphstream-project.org/doc/Advanced-Concepts/The-DGS-File-Format/

Sincerely,

Yoann 

Le 23 févr. 2022 à 09:23, LAVELLE Sylvain <sylvain.lavelle AT akka.eu> a écrit :

Hello graphstream users,

 

I have a question for the community. Here is my issue:

 

I need to create a directed graph object from a dot file. This works, but when there are two edges from one node to the same node, only one edge is created in the graph.

I am not sure if I am using the graphstream library correctly, or if the dot file is incorrect.

 

Graphstream version: 2.0

gs-core-2.0.jar

 

 

Here is an example of dot file:

*************

digraph G {

1->2;

1->2;

}

***********

From what I read of dot specification, this is valid (and some visualization tools like graphviz will draw two nodes with to edges from 1 to 2)

 

To create the graph, I use the following java code:

import org.graphstream.graph.Edge;
import org.graphstream.graph.implementations.MultiGraph;
import org.graphstream.stream.file.FileSource;
import org.graphstream.stream.file.FileSourceFactory;

/* ….  */

MultiGraph g = new MultiGraph("g",false, true); // graph id, strictChecking, autoCreate
FileSource fs = FileSourceFactory.sourceFor(filePath);
fs.addSink(g);

try {
    fs.readAll(filePath);
} catch( IOException e) {
    e.printStackTrace();
} finally {
    fs.removeSink(g);
}

//check how many connections:

System.out.println("number of edges: "+g.edges().count());

// print out: number of edges: 1

****************************

There is nothing special in the code, it is almost what is shown in the tutorial (https://graphstream-project.org/doc/Tutorials/Reading-files-using-FileSource/)

 

Can someone tell me what I should modify? Is it the graph creation? Using another type of graph or other parameters?

Should I modify the dot file?

 

Have a nice day,

Sylvain LAVELLE
Engineer


<image001.png>
7, boulevard Henri Ziegler — 31700 Blagnac — France
sylvain.lavelle AT akka.eu
www.akka-technologies.com

<image002.png>

<image003.png>

<image004.png>

<image005.png>

<image006.png>