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

.. only:: html

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

        :ref:`Go to the end <sphx_glr_download_auto_examples_svm_plot_custom_kernel.py>`
        to download the full example code. or to run this example in your browser via Binder

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

.. _sphx_glr_auto_examples_svm_plot_custom_kernel.py:


======================
带有自定义核函数的SVM
======================

使用支持向量机对样本进行分类的简单示例。它将绘制决策面和支持向量。

.. GENERATED FROM PYTHON SOURCE LINES 9-56



.. image-sg:: /auto_examples/svm/images/sphx_glr_plot_custom_kernel_001.png
   :alt: 3-Class classification using Support Vector Machine with custom kernel
   :srcset: /auto_examples/svm/images/sphx_glr_plot_custom_kernel_001.png
   :class: sphx-glr-single-img





.. code-block:: Python


    import matplotlib.pyplot as plt
    import numpy as np

    from sklearn import datasets, svm
    from sklearn.inspection import DecisionBoundaryDisplay

    # 导入一些数据来玩玩
    iris = datasets.load_iris()
    X = iris.data[:, :2]  # we only take the first two features. We could
    # 通过使用二维数据集来避免这种丑陋的切片
    Y = iris.target


    def my_kernel(X, Y):
        """我们创建一个自定义核函数：

                 (2  0)
    k(X, Y) = X  (    ) Y.T
                 (0  1)
    """
        M = np.array([[2, 0], [0, 1.0]])
        return np.dot(np.dot(X, M), Y.T)


    h = 0.02  # step size in the mesh

    # 我们创建一个SVM实例并拟合我们的数据。
    clf = svm.SVC(kernel=my_kernel)
    clf.fit(X, Y)

    ax = plt.gca()
    DecisionBoundaryDisplay.from_estimator(
        clf,
        X,
        cmap=plt.cm.Paired,
        ax=ax,
        response_method="predict",
        plot_method="pcolormesh",
        shading="auto",
    )

    # 还要绘制训练点
    plt.scatter(X[:, 0], X[:, 1], c=Y, cmap=plt.cm.Paired, edgecolors="k")
    plt.title("3-Class classification using Support Vector Machine with custom kernel")
    plt.axis("tight")
    plt.show()


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

   **Total running time of the script:** (0 minutes 0.043 seconds)


.. _sphx_glr_download_auto_examples_svm_plot_custom_kernel.py:

.. only:: html

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

    .. container:: binder-badge

      .. image:: images/binder_badge_logo.svg
        :target: https://mybinder.org/v2/gh/scikit-learn/scikit-learn/main?urlpath=lab/tree/notebooks/auto_examples/svm/plot_custom_kernel.ipynb
        :alt: Launch binder
        :width: 150 px

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

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

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

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

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: plot_custom_kernel.zip <plot_custom_kernel.zip>`


.. include:: plot_custom_kernel.recommendations


.. only:: html

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

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