Logarithmic y axis makes tick labels disappear [duplicate]

Question

Upon adding the line plt.yscale('log') to my simple plotting script

import numpy as np
residuals = np.loadtxt('res_jacobi.txt', skiprows=1)

import matplotlib.pyplot as plt
fig = plt.figure()

steps = np.arange(0, len(residuals), 1)

plt.plot(steps, residuals, label='$S$')

plt.xlabel("Step",fontsize=20)
plt.ylabel("$S$",fontsize=20)
plt.ylim(0.95 * min(residuals), 1.05 * max(residuals))
plt.yscale('log')

plt.savefig('jacobi-res.pdf', bbox_inches='tight', transparent=True)

the y labels disappear.

I'm sure there is simple fix for this but searching did not turn one up. Any help would be much appreciated.

Answer 1

The normal behavior for matplotlib is to only label major tick marks in log-scaling --- which are even orders of magnitude, e.g. {0.1, 1.0}. Your values are all between those. You can:

• rescale your axes to larger bounds,
  plt.gca().set_ylim(0.1, 1.0)
• label the tick-marks manually,
  plt.gca().yaxis.set_minor_formatter(FormatStrFormatter("%.2f"))