code: def plot(f, lcar=1.0e-1):
      
      import matplotlib
      import matplotlib.pyplot as plt
      import pygmsh
  
      geom = pygmsh.built_in.Geometry()
      geom.add_circle([0.0, 0.0, 0.0], 1.0, lcar, num_sections=4, compound=True)
      points, cells, _, _, _ = pygmsh.generate_mesh(geom, verbose=True)
  
      x = points[:, 0]
      y = points[:, 1]
      triang = matplotlib.tri.Triangulation(x, y, cells["triangle"])
  
      plt.tripcolor(triang, f(points.T), shading="flat")
      plt.colorbar()
  
      # Choose a diverging colormap such that the zeros are clearly
      # distinguishable.
      plt.set_cmap("coolwarm")
      # Make sure the color map limits are symmetric around 0.
      clim = plt.gci().get_clim()
      mx = max(abs(clim[0]), abs(clim[1]))
      plt.clim(-mx, mx)
  
      # circle outline
      circle = plt.Circle((0, 0), 1.0, edgecolor="k", fill=False)
      plt.gca().add_artist(circle)
  
      plt.gca().set_aspect("equal")
      plt.axis("off")
      return
docs: Plot function over a disk.