Inconsistent Matplotlib behaviour, running script multiple times leads to different outcomes. Posted as question on StackOverflow under URL: https://stackoverflow.com/questions/59101292/matplotlib-randomly-ignored-passed-parameters-at-each-execution

plot_file_a.png

plot_file_b.png

plot_file_c.png

plottest.py

import numpy as np

import sys

import matplotlib.pyplot as plt
import matplotlib.gridspec as gridspec
from mpl_toolkits.mplot3d import Axes3D


gs = gridspec.GridSpec(1, 2)
fig = plt.figure()
fig.suptitle('plotting test')

axes_real = fig.add_subplot(gs[0, 0], projection='3d')
axes_imag = fig.add_subplot(gs[0, 1], projection='3d')

rho = np.array([[0.3+0.2j, 0.2+0.1j], [0.2-0.1j, 0.3]])
rho_ref = np.array([[0.35+0.15j, 0.25+0.15j], [0.15-0.15j, 0.35]])

s = 0.1
sm = 0.5*s
alpha_mes = 0.40
alpha_ref = 0.1

for axes, M, M_ref in zip([axes_real, axes_imag], [rho.real, rho.imag], [rho_ref.real, rho_ref.imag]):
    axes.set_zlim(-1., 1.)
    axes.set_xticks([0.5, 1.5])
    axes.set_xticklabels(['$a$', '$b$'])
    axes.set_yticks([0.5, 1.5])
    axes.set_yticklabels(['$a$', '$b$'])
    axes.set_aspect(1.0)
    axes.bar3d(
        sm, sm, 0., 1.-s, 1.-s, M[0, 0],
        color='blue',
        alpha=alpha_mes,
        zsort='average')
    axes.bar3d(
        0., 0., 0., 1., 1., M_ref[0, 0],
        color='white',
        alpha=alpha_ref,
        zsort='average',
        edgecolor='black')
    axes.bar3d(
        1.+sm, sm, 0., 1.-s, 1.-s, 1.0,
        color='blue',
        alpha=alpha_mes,
        zsort='average')
    axes.bar3d(
        1., 0., 0., 1., 1., M_ref[0, 0],
        color='white',
        alpha=alpha_ref,
        zsort='average',
        edgecolor='black')
    axes.bar3d(
        sm, 1.+sm, 0, 1.-s, 1.-s, 1.0,
        color='blue',
        alpha=alpha_mes,
        zsort='average')
    axes.bar3d(
        0., 1., 0., 1., 1., M_ref[0, 0],
        color='white',
        alpha=alpha_ref,
        zsort='average',
        edgecolor='black')
    axes.bar3d(
        1.+sm, 1.+sm, 0., 1.-s, 1.-s, M[0, 0],
        color='blue',
        alpha=alpha_mes,
        zsort='average')
    axes.bar3d(
        1., 1., 0., 1., 1., M_ref[0, 0],
        color='white',
        alpha=alpha_ref,
        zsort='average',
        edgecolor='black')

axes_real.view_init(elev=25., azim=45)
axes_imag.view_init(elev=25., azim=45)
# plt.show()

fig.savefig('plot_file_'+sys.argv[1]+'.png')

Resolved in https://stackoverflow.com/a/59131715/2398574