source: orange/docs/widgets/rst/unsupervized/interactiongraph.rst @ 11778:ecd4beec2099

Revision 11778:ecd4beec2099, 2.0 KB checked in by Ales Erjavec <ales.erjavec@…>, 5 months ago (diff)

Use new SVG icons in the widget documentation.

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1.. _Interaction Graph:
2
3Interaction Graph
4=================
5
6.. image:: ../../../../Orange/OrangeWidgets/Unsupervised/icons/InteractionGraph_48.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
27in his work on `attribute interactions <http://stat.columbia.edu/~jakulin/Int/>`_.
28The interaction is defined as the difference between the sum of individual
29attribute information gains and the information gain of their cartesian
30product. The interaction can be negative (e.g. when the attributes are
31correlated), or positive (e.g. when the class is related to the xor of the
32two attributes).
33
34The widget uses an external application for drawing graphs,
35`GraphViz <http://www.graphviz.org/>`_. It does not come with Orange, so you
36will need to install separately for the entire widget to work.
37
38The widget will be completely redesigned in the nearest future, so we here
39only give its most basic description.
40
41
42.. image:: images/InteractionGraph-Small.png
43
44The widget is comprised of three parts. In the leftmost the user can select
45the attributes among which she or he wants to compute the interactions. The
46middle part contains all pairs of attributes - or all interesting pairs,
47if :obj:`Show only important interactions` is checked. For attributes which
48are in positive interaction, the blue parts at the left and the right end of
49the bar represent the individual information gains and the green part in the
50middle represents the interaction. For those in negative interaction, the red
51part is the interaction, which can be interpreted as the amount of information
52conveyed by both attributes, while the blue parts to the left and right are
53each attribute's individual contribution.
54
55The right part of the widget shows a graph of interactions.
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