Re: A few questions about the graph layout algorithm

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

Hi Youri, 

- The Image "looks" like a normal SpingBox Layout to me. 

- Yes, it is normal for the layout to send so much events. Since you are 
using the LayoutRunner, you have the layout running in its own thread in a 
"kind of" infinite loop. If you want more control over the number of 
iterations of the layout and/or the number of events, you could do something 
like this in your code: 

// Compute the layout in this thread. 
// Need a loop with a stop condition of your choice. 
while(layout.getStabilization() < 0.9){
        layout.compute();
}  

// Only plug the sink AFTER the computation of the layout
layout.addSink(this);         

// One last computation in order to 
// recive one event for each node.
layout.compute(); 

- About the most performant algorithm, I can't really say. Plus, it depends 
on your definition of "performant".



Yoann



> On Mar 7, 2015, at 9:03 PM, youri flement 
> <youri.flement AT ugent.be>
>  wrote:
> 
> Hello, 
> 
> 
> I'm sorry this is in English, my French is not that good... 
> 
> I'm trying to integrate the GraphStream SpringBox layout algorithm in an 
> application I'm developing for school and I have a few questions: 
> 
>       • Is the image attached a valid rendering of a connected graph with 3 
> edges using this layout algorithm? (I had to alter the coordinates a bit 
> because I only received x- and y-values between 0 and 1)
>       • Is it normal for the layout algorithm to sent a very high amount of 
> events, even for small graphs? (for example, the rendering above gave me 
> 771 nodeAttributeChanged events)
>       • Which is the most performant algorithm: LinLog or SpringBox?
> 
> 
> Kind regards,
> Youri
> 
> 
> 
> PS. This is somewhat how I'm using the layout algorithm:
> 
>          public MyClass() {
>         SpringBox layout = new SpringBox();
>         layout.addSink(this);         
> 
>         layout.nodeAdded("0", 1000, "a");
>         layout.nodeAdded("0", 2000, "b");
>         layout.edgeAdded("0", 3000, "aToB", "a", "b", true);
> 
>         LayoutRunner runner = new LayoutRunner(layout, layout);
>     }
> 
>     @Overide
>     public void nodeAttributeChanged(...) {
>          // adjust position of the changed node
>     }
> 
> <SmallGraph.png>