.. _sphx_glr_auto_examples_balance_ex_smote.py:


====================
SMOTE class balancer
====================

This example creates an imbalanced classification dataset, and applies the
`Synthetic Minority Observation TEchnique (SMOTE) <https://bit.ly/2qH3dIX>`_
class balancing technique in order to balance it by supplementing synthetic
minority class observations.

.. raw:: html

   <br/>




.. image:: /auto_examples/balance/images/sphx_glr_ex_smote_001.png
    :align: center





.. code-block:: python

    print(__doc__)

    # Author: Taylor Smith <taylor.smith@alkaline-ml.com>

    from matplotlib import pyplot as plt
    from sklearn.datasets import make_blobs
    from sklearn.utils.validation import check_random_state
    from skoot.balance import smote_balance

    plt.figure(figsize=(6, 4))

    # #############################################################################
    # make blobs and grossly undersample one of them
    random_state = check_random_state(42)
    n_samples = 1000
    X, y = make_blobs(n_samples=n_samples, centers=2,
                      random_state=random_state,
                      n_features=5, cluster_std=4.5)

    minority_mask = y == 0
    sample_mask = ((~minority_mask) |
                   (minority_mask &
                    (random_state.rand(minority_mask.shape[0]) < 0.05)))

    X, y = X[sample_mask, :], y[sample_mask]

    plt.subplot(121)
    plt.scatter(X[:, 0], X[:, 1], c=y)
    plt.title("Initial imbalanced dataset")

    # #############################################################################
    # Balance the dataset
    X_balance, y_balance = smote_balance(X, y, balance_ratio=0.2, random_state=42)

    plt.subplot(122)
    plt.scatter(X_balance[:, 0], X_balance[:, 1],
                c=y_balance)
    plt.title("Balanced dataset")
    plt.show()

**Total running time of the script:** ( 0 minutes  0.022 seconds)



.. only :: html

 .. container:: sphx-glr-footer


  .. container:: sphx-glr-download

     :download:`Download Python source code: ex_smote.py <ex_smote.py>`



  .. container:: sphx-glr-download

     :download:`Download Jupyter notebook: ex_smote.ipynb <ex_smote.ipynb>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.readthedocs.io>`_