  vn0 = 2.^[5 : 10] - 1;
  venorminf = [  3.2189644400852924e-03 ...
                 8.0357767939931435e-04 ...
                 2.0082180979019704e-04 ...
                 5.0200916270171092e-05 ...
                 1.2549946873496864e-05 ...
                 3.1374743667544891e-06];

  % ... produce standard log-log plot using Matlab's loglog command:
  xdata = vn0 + 1;
  ydata = venorminf;
  figure('DefaultAxesFontSize', 20);
  H = loglog(xdata, ydata, '-o');
  set(H, 'LineWidth',3, 'MarkerSize',10);
  grid on;
  legend(H, 'infinity norm of true error');
  xlabel('log_{10} (1 / h)');
  ylabel('log_{10} (||u - u_h||)');
  print -dpng figconvorderloglog.png

