[SOLVED] Noverlap

Algorithms and parameters to put data in space
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elijah
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[SOLVED] Noverlap

Post by elijah » 04 Feb 2011 21:23

Noverlap seems to take a long time and have a very hard time with large networks. I've been running it on a 55,000 node 1-edge to 1-node network (just to look at the whole thing) and it takes a tremendous amount of time between ticks and does very little. I'm wondering if I'm using it wrong or if there are ways to optimize this. My expectation was in setting up the layout manually or using different algorithms and then Noverlap would just sort of spread out the clustered results in a timely manner.

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jacomyma
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Re: Noverlap

Post by jacomyma » 08 Feb 2011 15:59

Noverlap could be improved... Here is how it works:
- First it separates the graph in a grid of squares.
- Then it gets which nodes are on which squares (of course a node could be on several squares, especially if it's big)
- Then, it gets a list of "proximity relations", which approximate if two nodes are in the same area. Two nodes have a "proximity relation" if they are on a common square...
- Then it tests each of these relations to eliminate nodes that actually do not overlap
- And it applies a repulsive force between the nodes that overlap.

Noverlap is then very slow if many nodes are in the same square (many proximity relations).
I'll try to put this setting (grid precision) as an editable parameter.
Nevertheless, you can improve performance by avoiding isolated nodes far away from the rest of the graph. I propose you a very ugly drawing to explain the problem...
Attachments
crappy explanation.png
This is my explanation of a way to improve perfs for Noverlap. This picture isn't made by a child, but by me. It's my chef d'oeuvre.
Last edited by jacomyma on 09 Feb 2011 08:38, edited 1 time in total.

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jacomyma
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Re: Noverlap

Post by jacomyma » 08 Feb 2011 16:56

Ok, I've updated the Noverlap plugin, now featuring the gridSize setting. You have gridSize² squares in the grid.

Try to put gridSize to 100 or 500 to see if it improves performance.

Plugin update available in the Gephi build-in module center, or there:
http://gephi.org/plugins/noverlap/

elijah
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Re: Noverlap

Post by elijah » 14 Feb 2011 18:48

Just got notified of the update, I'll give it a go later today.

tiagofpimentel
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Re: [SOLVED] Noverlap

Post by tiagofpimentel » 25 Aug 2014 11:09

Nice work!
How do I set de GridSize?
thx

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