import numpy as np

import matplotlib.pyplot as plt

def show_slice(Z, name):

rows,cols = Z.shape

fig = plt.figure(figsize=(cols/4.,rows/4.), dpi=72)

ax = plt.subplot(111)

A = np.arange(rows*cols).reshape(rows,cols)

plt.imshow(Z, cmap='Purples', extent=[0,cols,0,rows],

vmin=0, vmax=1, interpolation='nearest', origin='upper')

plt.xticks([]), plt.yticks([])

for pos in ['top', 'bottom', 'right', 'left']:

ax.spines[pos].set_edgecolor('k')

ax.spines[pos].set_alpha(.25)

plt.savefig('../figures/%s' % name, dpi=72)

#plt.show()

rows,cols = 5, 9

Z = np.zeros((rows,cols))+.1

show_slice(Z, 'slice-Z.png')

Z = np.zeros((rows,cols))+.1

Z[...] = 1

show_slice(Z, 'slice-Z[...].png')

Z = np.zeros((rows,cols))+.1

Z[:,::2] = 1

show_slice(Z, 'slice-Z[:,::2].png')

Z = np.zeros((rows,cols))+.1

Z[::2,:] = 1

show_slice(Z, 'slice-Z[::2,:].png')

Z = np.zeros((rows,cols))+.1

Z[1,1] = 1

show_slice(Z, 'slice-Z[1,1].png')

Z = np.zeros((rows,cols))+.1

Z[:,0] = 1

show_slice(Z, 'slice-Z[:,0].png')

Z = np.zeros((rows,cols))+.1

Z[0,:] = 1

show_slice(Z, 'slice-Z[0,:].png')

Z = np.zeros((rows,cols))+.1

Z[2:,2:] = 1

show_slice(Z, 'slice-Z[2:,2:].png')

Z = np.zeros((rows,cols))+.1

Z[:-2,:-2] = 1

show_slice(Z, 'slice-Z[:-2,:-2].png')

Z = np.zeros((rows,cols))+.1

Z[2:4,2:4] = 1

show_slice(Z, 'slice-Z[2:4,2:4].png')

Z = np.zeros((rows,cols))+.1

Z[::2,::2] = 1

show_slice(Z, 'slice-Z[::2,::2].png')

Z = np.zeros((rows,cols))+.1

Z[3::2,3::2] = 1

show_slice(Z, 'slice-Z[3::2,3::2].png')