@@ -7,10 +7,14 @@ Multiclass and multilabel algorithms
7
7
8
8
.. currentmodule :: sklearn.multiclass
9
9
10
- The :mod: `sklearn.multiclass ` module implements *meta-estimators * to perform
11
- ``multiclass `` and ``multilabel `` classification. Those meta-estimators are
12
- meant to turn a binary classifier or a regressor into a multi-class/label
13
- classifier.
10
+ .. warning ::
11
+ All classifiers in scikit-learn do multiclass classification
12
+ out-of-the-box. You don't need to use the :mod: `sklearn.multiclass ` module
13
+ unless you want to experiment with different multiclass strategies.
14
+
15
+ The :mod: `sklearn.multiclass ` module implements *meta-estimators * to solve
16
+ ``multiclass `` and ``mult
10000
ilabel `` classification problems
17
+ by decomposing such problems into binary classification problems.
14
18
15
19
- **Multiclass classification ** means a classification task with more than
16
20
two classes; e.g., classify a set of images of fruits which may be oranges,
@@ -25,8 +29,8 @@ classifier.
25
29
education at the same time or none of these.
26
30
27
31
- **Multioutput-multiclass classification ** and **multi-task classification **
28
- means that an estimators have to handle
29
- jointly several classification tasks. This is a generalization
32
+ means that a single estimator has to handle
33
+ several joint classification tasks. This is a generalization
30
34
of the multi-label classification task, where the set of classification
31
35
problem is restricted to binary classification, and of the multi-class
32
36
classification task. *The output format is a 2d numpy array. *
@@ -44,16 +48,15 @@ classifier.
44
48
classification task with different model formulations. For
45
49
more information, see the relevant estimator documentation.
46
50
47
- Estimators in this module are meta-estimators. For example, it is possible to
48
- use these estimators to turn a binary classifier or a regressor into a
49
- multiclass classifier. It is also possible to use these estimators with
50
- multiclass estimators in the hope that their generalization error or runtime
51
- performance improves .
51
+ All scikit-learn classifiers are capable of multiclass classification,
52
+ but the meta- estimators offered by :mod: ` sklearn.multiclass `
53
+ permit changing the way they handle more than two classes
54
+ because this may have an effect on classifier performance
55
+ (either in terms of generalization error or required computational resources) .
52
56
53
- You don't need to use these estimators unless you want to experiment with
54
- different multiclass strategies: all classifiers in scikit-learn support
55
- multiclass classification out-of-the-box. Below is a summary of the
56
- classifiers supported by scikit-learn grouped by strategy:
57
+ Below is a summary of the classifiers supported by scikit-learn
58
+ grouped by strategy; you don't need the meta-estimators in this class
59
+ if you're using one of these unless you want custom multiclass behavior:
57
60
58
61
- Inherently multiclass: :ref: `Naive Bayes <naive_bayes >`,
59
62
:class: `sklearn.lda.LDA `,
@@ -66,16 +69,15 @@ Some estimators also support multioutput-multiclass classification
66
69
tasks :ref: `Decision Trees <tree >`, :ref: `Random Forests <forest >`,
67
70
:ref: `Nearest Neighbors <neighbors >`.
68
71
69
-
70
72
.. warning ::
71
73
72
- For the moment , no metric supports the multioutput-multiclass
73
- classification task.
74
+ At present , no metric in :mod: ` sklearn.metrics `
75
+ supports the multioutput-multiclass classification task.
74
76
75
77
Multilabel classification format
76
78
================================
77
79
78
- In multilabel learning, the joint set of binary classification task
80
+ In multilabel learning, the joint set of binary classification tasks
79
81
is expressed with either a sequence of sequences or a label binary indicator
80
82
array.
81
83
0 commit comments