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

.. only:: html

    .. meta::
        :keywords: codex

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

        :ref:`Go to the end <sphx_glr_download_gallery_specialty_plots_hinton_demo.py>`
        to download the full example code.

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

.. _sphx_glr_gallery_specialty_plots_hinton_demo.py:


===============
Hinton diagrams
===============

Hinton diagrams are useful for visualizing the values of a 2D array (e.g.
a weight matrix): Positive and negative values are represented by white and
black squares, respectively, and the size of each square represents the
magnitude of each value.

Initial idea from David Warde-Farley on the SciPy Cookbook

.. GENERATED FROM PYTHON SOURCE LINES 13-46



.. image-sg:: /gallery/specialty_plots/images/sphx_glr_hinton_demo_001.png
   :alt: hinton demo
   :srcset: /gallery/specialty_plots/images/sphx_glr_hinton_demo_001.png, /gallery/specialty_plots/images/sphx_glr_hinton_demo_001_2_00x.png 2.00x
   :class: sphx-glr-single-img





.. code-block:: Python

    import matplotlib.pyplot as plt
    import numpy as np


    def hinton(matrix, max_weight=None, ax=None):
        """Draw Hinton diagram for visualizing a weight matrix."""
        ax = ax if ax is not None else plt.gca()

        if not max_weight:
            max_weight = 2 ** np.ceil(np.log2(np.abs(matrix).max()))

        ax.patch.set_facecolor('gray')
        ax.set_aspect('equal', 'box')
        ax.xaxis.set_major_locator(plt.NullLocator())
        ax.yaxis.set_major_locator(plt.NullLocator())

        for (x, y), w in np.ndenumerate(matrix):
            color = 'white' if w > 0 else 'black'
            size = np.sqrt(abs(w) / max_weight)
            rect = plt.Rectangle([x - size / 2, y - size / 2], size, size,
                                 facecolor=color, edgecolor=color)
            ax.add_patch(rect)

        ax.autoscale_view()
        ax.invert_yaxis()


    if __name__ == '__main__':
        # Fixing random state for reproducibility
        np.random.seed(19680801)

        hinton(np.random.rand(20, 20) - 0.5)
        plt.show()


.. _sphx_glr_download_gallery_specialty_plots_hinton_demo.py:

.. only:: html

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

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

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

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

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

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

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


.. only:: html

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

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