.. _specialty_plots-hinton_demo: specialty_plots example code: hinton_demo.py ============================================ .. plot:: /home/tcaswell/source/p/matplotlib/doc/mpl_examples/specialty_plots/hinton_demo.py :: """ Demo of a function to create 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 """ 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__': hinton(np.random.rand(20, 20) - 0.5) plt.show() Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)