============================= [DEPRECATED] brew

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[DEPRECATED] brew: A Multiple Classifier Systems API

This project has not being maintained for a while, so as of now we have abandoned it. If you want an alternative ensemble library in python, we recommend DESLib instead.

| This project was started in 2014 by Dayvid Victor and Thyago Porpino | for the Multiple Classifier Systems class at Federal University of Pernambuco.

| The aim of this project is to provide an easy API for Ensembling, Stacking, | Blending, Ensemble Generation, Ensemble Pruning, Dynamic Classifier Selection, | and Dynamic Ensemble Selection.

Features

General: Ensembling, Stacking and Blending.
Ensemble Classifier Generators: Bagging, Random Subspace, SMOTE-Bagging, ICS-Bagging, SMOTE-ICS-Bagging.
Dynamic Selection: Overall Local Accuracy (OLA), Local Class Accuracy (LCA), Multiple Classifier Behavior (MCB), K-Nearest Oracles Eliminate (KNORA-E), K-Nearest Oracles Union (KNORA-U), A Priori Dynamic Selection, A Posteriori Dynamic Selection, Dynamic Selection KNN (DSKNN).
Ensemble Combination Rules: majority vote, min, max, mean and median.
Ensemble Diversity Metrics: Entropy Measure E, Kohavi Wolpert Variance, Q Statistics, Correlation Coefficient p, Disagreement Measure, Agreement Measure, Double Fault Measure.
Ensemble Pruning: Ensemble Pruning via Individual Contribution (EPIC).

Example

.. code-block:: python

    import numpy as np
    import matplotlib.pyplot as plt
    import matplotlib.gridspec as gridspec
    import itertools

    import sklearn

    from sklearn.linear_model import LogisticRegression
    from sklearn.svm import SVC
    from sklearn.ensemble import RandomForestClassifier

    from brew.base import Ensemble, EnsembleClassifier
    from brew.stacking.stacker import EnsembleStack, EnsembleStackClassifier
    from brew.combination.combiner import Combiner

    from mlxtend.data import iris_data
    from mlxtend.evaluate import plot_decision_regions

    # Initializing Classifiers
    clf1 = LogisticRegression(random_state=0)
    clf2 = RandomForestClassifier(random_state=0)
    clf3 = SVC(random_state=0, probability=True)

    # Creating Ensemble
    ensemble = Ensemble([clf1, clf2, clf3])
    eclf = EnsembleClassifier(ensemble=ensemble, combiner=Combiner('mean'))

    # Creating Stacking
    layer_1 = Ensemble([clf1, clf2, clf3])
    layer_2 = Ensemble([sklearn.clone(clf1)])

    stack = EnsembleStack(cv=3)

    stack.add_layer(layer_1)
    stack.add_layer(layer_2)

    sclf = EnsembleStackClassifier(stack)

    clf_list = [clf1, clf2, clf3, eclf, sclf]
    lbl_list = ['Logistic Regression', 'Random Forest', 'RBF kernel SVM', 'Ensemble', 'Stacking']

    # Loading some example data
    X, y = iris_data()
    X = X[:,[0, 2]]

    # WARNING, WARNING, WARNING
    # brew requires classes from 0 to N, no skipping allowed
    d = {yi : i for i, yi in enumerate(set(y))}
    y = np.array([d[yi] for yi in y])

    # Plotting Decision Regions
    gs = gridspec.GridSpec(2, 3)
    fig = plt.figure(figsize=(10, 8))

    itt = itertools.product([0, 1, 2], repeat=2)

    for clf, lab, grd in zip(clf_list, lbl_list, itt):
        clf.fit(X, y)
        ax = plt.subplot(gs[grd[0], grd[1]])
        fig = plot_decision_regions(X=X, y=y, clf=clf, legend=2)
        plt.title(lab)
    plt.show()

.. image:: https://raw.githubusercontent.com/viisar/brew/master/docs/sources/img/iris_decision_regions_2d.png :alt: decision regions plots :align: center

Dependencies

Python 2.7+
scikit-learn >= 0.15.2
Numpy >= 1.6.1
SciPy >= 0.9
Matplotlib >= 0.99.1 (examples, only)
mlxtend (examples, only)

Installing

You can easily install brew using pip::

pip install brew

or, if you prefer an up-to-date version, get it from here::

pip install git+https://github.com/viisar/brew.git

Important References

Kuncheva, Ludmila I. Combining pattern classifiers: methods and algorithms. John Wiley & Sons, 2014.
Zhou, Zhi-Hua. Ensemble methods: foundations and algorithms. CRC Press, 2012.

viisar / brew

readme