.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "sklearn_ensae_course/plot_sgd_separator.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        Click :ref:`here <sphx_glr_download_sklearn_ensae_course_plot_sgd_separator.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_sklearn_ensae_course_plot_sgd_separator.py:


SGDClassifier
=============

Show the boundary computed by a
`SGDClassifier <http://scikit-learn.org/stable/modules/generated/sklearn.linear_model.SGDClassifier.html>`_.

.. GENERATED FROM PYTHON SOURCE LINES 9-48



.. image-sg:: /sklearn_ensae_course/images/sphx_glr_plot_sgd_separator_001.png
   :alt: plot sgd separator
   :srcset: /sklearn_ensae_course/images/sphx_glr_plot_sgd_separator_001.png
   :class: sphx-glr-single-img





.. code-block:: default

    import numpy as np
    import matplotlib.pyplot as plt
    from sklearn.linear_model import SGDClassifier
    from sklearn.datasets import make_blobs


    def plot_sgd_separator():
        # we create 50 separable points
        X, Y = make_blobs(n_samples=50, centers=2,
                          random_state=0, cluster_std=0.60)

        # fit the model
        clf = SGDClassifier(loss="hinge", alpha=0.01,
                            max_iter=200, fit_intercept=True)
        clf.fit(X, Y)

        # plot the line, the points, and the nearest vectors to the plane
        xx = np.linspace(-1, 5, 10)
        yy = np.linspace(-1, 5, 10)

        X1, X2 = np.meshgrid(xx, yy)
        Z = np.empty(X1.shape)
        for (i, j), val in np.ndenumerate(X1):
            x1 = val
            x2 = X2[i, j]
            p = clf.decision_function([[x1, x2]])
            Z[i, j] = p[0]
        levels = [-1.0, 0.0, 1.0]
        linestyles = ['dashed', 'solid', 'dashed']
        colors = 'k'

        ax = plt.axes()
        ax.contour(X1, X2, Z, levels, colors=colors, linestyles=linestyles)
        ax.scatter(X[:, 0], X[:, 1], c=Y, cmap=plt.cm.Paired)

        ax.axis('tight')


    plot_sgd_separator()


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** ( 0 minutes  0.624 seconds)


.. _sphx_glr_download_sklearn_ensae_course_plot_sgd_separator.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example


    .. container:: sphx-glr-download sphx-glr-download-python

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

    .. container:: sphx-glr-download sphx-glr-download-jupyter

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


.. only:: html

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

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