source: orange/docs/widgets/rst/associate/associationrulesexplorer.rst @ 11404:1a7b773d7c7b

Revision 11404:1a7b773d7c7b, 2.7 KB checked in by Ales Erjavec <ales.erjavec@…>, 14 months ago (diff)

Replaced the use of :code: role with :obj:

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1.. _Association Rules Explorer:
2
3Association Rules Tree Viewer
4=============================
5
6.. image:: ../icons/AssociationRulesExplorer.png
7
8A tree-like association rules viewer
9
10Signals
11-------
12
13Inputs:
14   - Association Rules
15      A list of rules
16
17
18Outputs:
19   - None
20
21
22Description
23-----------
24
25This widget is a tree-like association rules viewer.
26
27The widget can be used to find all the rules that include a particular
28condition on the left-hand side. The below snapshot is made on the Titanic
29data set, using the filter as shown on the page on the
30:ref:`Association Rules Filter`.
31
32.. image:: images/AssociationRulesTreeViewer-closed.png
33   :alt: Association Rules Tree Viewer Widget
34
35Say that we are interested in rules regarding the survival of adults. By
36opening the branch "age=adult", we discover four rules that contain this
37condition as the sole condition on the left-hand side, while the right-hand
38sides contain different combinations of sex, status and survival.
39
40.. image:: images/AssociationRulesTreeViewer-semi-open.png
41   :alt: Association Rules Tree Viewer Widget
42
43Besides that, there are rules with (at least) two conditions on the
44left-hand side, "age=adult" and "sex=male"; to explore these rules,
45we would need to open the corresponding branch.
46
47Each leaf of the tree corresponds to one particular ordering of the
48left-hand side conditions in a particular rule. Turned around, this
49means that each rule appears in many places in the tree. As the completely
50open tree below shows, the rule "age=adult & sex=male -> status=crew"
51appears in two places (the seventh and the eleventh row).
52
53On the left-hand side of the widget, we can choose the measures we want
54to observe. Let L, R and B be the number of examples that fit the left,
55the right and both sides of the rule, respectively, and N the total number
56of examples in the data set. The measures are then defined as follows
57
58   - confidence = B / L
59   - confidence = B / L
60   - coverage = L / N
61   - strength = R / L
62   - lift = N * B / (L * R)
63   - leverage = N * B - L * R
64
65
66
67:obj:`Tree depth` sets the depth to which the tree is expanded. If, it is set
68to, for instance, three, then the leaves corresponding to rules with five
69conditions will, besides the right-hand side, also contain the two conditions
70which are not shown in the branches.
71
72With :obj:`Display whole rules` we can decide whether we want the entire rule
73(including the information that is already contained in the branches, that
74is, in the path from the root to the rule) reprinted again in the leaf.
75
76Examples
77--------
78
79This widget is typically used with the :ref:`Association Rules` and possibly
80:ref:`Association Rules Filter`. A typical schema is shown below.
81
82.. image:: images/AssociationRules-Schema.png
83   :alt: Association Rules
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