source: orange/docs/widgets/rst/associate/associationrulesfilter.rst @ 11050:e3c4699ca155

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1.. _Association Rules Filter:
2
3Association Rules Filter
4========================
5
6.. image:: ../icons/AssociationRulesFilter.png
7
8A widget for printing out the rules and for their manual exploration and selection.
9
10Signals
11-------
12
13Inputs:
14   - Association Rules
15      A list of rules
16
17
18Outputs:
19   - Association Rules
20      Selected rules
21
22
23
24Description
25-----------
26
27This widget can be used for three purposes:
28   - graphically showing the confidence and support of the induced rules
29   - selecting a subset of rules based on their confidence and support
30   - listing the induced rules and the corresponding measures of quality
31
32The columns of the grid on the left hand side of the widget represent different supports and the rows represents confidences. The scale is given above the grid: for the case in this snapshot, support goes from 28% to 75% and the confidence ranges from 29% to 100%. Each cell is colored according to the number of rules with that particular support and confidence - the darker the cell, the more rules are inside it.
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34You can select a part of the grid. In the snapshot we selected the rules with supports between 36% and 66% and confidences from 33% to 82%.
35
36When the widget receives certain data, it shows the area containing all the rules. You can :obj:`Zoom` in to enlarge the selected part, push :obj:`Show All` to see the region with the rules again, or :obj:`No Zoom` to see the region with support and confidence from 0 to 1. :obj:`Unselect` removes the selection.
37
38If nothing is selected, the widget outputs all rules.
39
40On the right hand side of the widget there is a list of the selected rules. The checkboxes above can be used to select the measures of rule quality that we are interested in. Let L, R and B be the number of examples that fit the left, the right and both sides of the rule, respectively, and N the total number of examples in the data set. The measures are then defined as follows
41
42   - support = B / N
43   - confidence = B / L
44   - coverage = L / N
45   - strength = R / L
46   - lift = N * B / (L * R)
47   - leverage = N * B - L * R
48
49
50
51With the buttons below you can :obj:`Save Rules` into a tab-delimited file or :obj:`Send Rules` to the widget connected to the output. The latter is only enabled if :obj:`Send rules automatically` is unchecked. When it is checked, the rules are put on the widget's output automatically at every selection change.
52
53Examples
54--------
55
56This widget is used with the `Association Rules <AssociationRules.htm>`_ and maybe with a tree-like `Association Rules Tree Viewer <AssociationRulesTreeViewer.htm>`_. The typical schema is shown below.
57
58.. image:: images/AssociationRules-Schema.png
59   :alt: Association Rules
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