"""
Plot the sparsity pattern of arrays
"""

from matplotlib.pyplot import figure, show
import numpy

fig = figure()
ax1 = fig.add_subplot(221)
ax2 = fig.add_subplot(222)
ax3 = fig.add_subplot(223)
ax4 = fig.add_subplot(224)

x = numpy.random.randn(20, 20)
x[5] = 0.
x[:, 12] = 0.

ax1.spy(x, markersize=5)
ax2.spy(x, precision=0.1, markersize=5)

ax3.spy(x)
ax4.spy(x, precision=0.1)

show()