source: orange/docs/widgets/rst/unsupervized/interactiongraph.rst @ 11050:e3c4699ca155

Revision 11050:e3c4699ca155, 1.9 KB checked in by Miha Stajdohar <miha.stajdohar@…>, 16 months ago (diff)

Widget docs From HTML to Sphinx.

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1.. _Interaction Graph:
2
3Interaction Graph
4=================
5
6.. image:: ../icons/MDS.png
7
8Graph of interactions between attributes
9
10Signals
11-------
12
13Inputs:
14   - Examples (ExampleTable)
15      A table of examples
16
17Outputs:
18   - Selected Examples
19      ???
20   - Attribute Pair
21      ???
22   - Selected Attributes
23      ???
24
25
26The widget computes interactions between attributes as defined by Aleks Jakulin in his work on `attribute interactions <http://stat.columbia.edu/~jakulin/Int/>`_. The interaction is defined as the difference between the sum of individual attribute information gains and the information gain of their cartesian product. The interaction can be negative (e.g. when the attributes are correlated), or positive (e.g. when the class is related to the xor of the two attributes).
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28The widget uses an external application for drawing graphs, `GraphViz <http://www.graphviz.org/>`_. It does not come with Orange, so you will need to install separately for the entire widget to work.
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30The widget will be completely redesigned in the nearest future, so we here only give its most basic description.
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32
33.. image:: images/InteractionGraph-Small.png
34
35The widget is comprised of three parts. In the leftmost the user can select the attributes among which she or he wants to compute the interactions. The middle part contains all pairs of attributes - or all interesting pairs, if :obj:`Show only important interactions` is checked. For attributes which are in positive interaction, the blue parts at the left and the right end of the bar represent the individual information gains and the green part in the middle represents the interaction. For those in negative interaction, the red part is the interaction, which can be interpreted as the amount of information conveyed by both attributes, while the blue parts to the left and right are each attribute's individual contribution.
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37The right part of the widget shows a graph of interactions.
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