.. _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




.. image:: /gallery/specialty_plots/images/sphx_glr_hinton_demo_001.png
    :align: center





.. code-block:: python

    import numpy as np
    import matplotlib.pyplot as plt


    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.log(np.abs(matrix).max()) / np.log(2))

        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(np.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()

**Total running time of the script:** ( 0 minutes  0.214 seconds)



.. only :: html

 .. container:: sphx-glr-footer


  .. container:: sphx-glr-download

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



  .. container:: sphx-glr-download

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


.. only:: html

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

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