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Showing (meta) edges between meta nodes

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2013-04-18
2013-04-22
  • David Monarchi
    David Monarchi
    2013-04-18

    Hi -

    System: Win Pro 7 x64; Tulip 4.2

    Apologies in advance if this has been asked and answered.  I did a search and couldn't find anything, but I may be asking the question incorrectly.

    I have created a set of subgraphs using Equal Value Clustering and then created a meta graph on those subgraphs using Quotient Clustering.  The result is exactly what I want - a set of spheres containing graphs, each labeled correctly - except that there are no edges between the subgraphs.  I must be misunderstanding the parameters on quotient clustering.  I would like to have edges between the subgraphs that are proportional to the number of edges between the elements of each subgraph. 

    Any assistance/direction would be greatly appreciated.  :-)

    Thanks.

    David

     
  • Patrick Mary
    Patrick Mary
    2013-04-18

    I suppose that  "Edge color interpolation'" is set while rendering the quotient graph.
    Thus, as the meta nodes default color is fully transparent the interpolated color of an edge
    between two meta nodes is also fully transparent.
    Uncheck the corresponding check box in the  "Scene" tab panel of the node link diagram view
    to remove this interpolation.

    Hope this helps
    Patrick

     
  • Patrick Mary
    Patrick Mary
    2013-04-18

    Don't forget to click on the 'Apply changes' button at the top right corner
    of the "Scene" tab panel to validate and see your changes.

     
  • David Monarchi
    David Monarchi
    2013-04-18

    Thanks, Patrick!  That was exactly what I needed to know.  I had missed the fact that the default color on a meta node is transparent. 

    If I may extend this just a bit further, I have a couple of additional questions related to the graph with the meta nodes.
    1) The size of the meta node seems unrelated to the number of nodes within it.  Is there a way to control this at the time the quotient cluster is created?
    2) edgeCardinality is zero for both the meta nodes and the meta edges.  I wanted to make the meta edges proportional in size to the number of edges between each meta node, but I appeared to have missed something.  (The sizes of the meta edges are not constant, but I can't determine what the values are based upon.)

    Thanks again for your help.  It is greatly appreciated.  :-)

    David

     
  • Patrick Mary
    Patrick Mary
    2013-04-22

    David,

    1) when calling the Quotient Clustering algorithm
    the size of the meta nodes is updated only if the parameter
    'layout quotient graph(s)' is set to true.
    2) if computed 'edge cardinality' must have a non zero value
    for meta edges (value for meta nodes is always 0).
    The size of the meta edges can be different is
    'Enable size interpolation' is set in the the 'Scene' panel of
    the node link diagram view.
    To have the size of the meta edges proportional to the 'edge cardinality'
    values, you can use the 'Metric Mapping' algorithm.
    This algorithm needs a metric property as input but the 'edge cardinality'
    property is not a metric property so you need to copy the 'edge cardinality'
    values into a metric property.

    At this time Tulip does not provide a way to do this; thus I attached a file
    containing a simple metric plugin named "Copy integer property into metric"
    which allows to do the copy.
    This plugin is written in Python, so you just have to install this file
    in the lib/tulip/python subdirectory of your Tulip installation directory
    and this python plugin will be automatically loaded by Tulip at start time.

    Hope this helps
    Patrick

     
  • David Monarchi
    David Monarchi
    2013-04-22

    Thank you, Patrick, for your very kind assistance and the Python plugin. :-) However, the edgeCardinality property is 0 for all of the meta edges. I understand that it would be 0 for the meta nodes, but don't know why it's 0 for the meta edges. Is this due to the fact that I have a directed graph? There should be a different number of edges going in each direction between any pair of meta nodes. Ideally, there would be two meta edges between such a pair of meta nodes, each with a different cardinality.

    If necessary, I can write a routine to compute these cardinalities, but I don't want to do so if the machinery is already in place. :-)

    Thank you again!

    David