def plot(f, lcar=0.05):
    """Plot function over a disk.
    """
    import matplotlib
    import matplotlib.pyplot as plt
    import dmsh
    geo = dmsh.Circle([0.0, 0.0], 1.0)
    points, cells = dmsh.generate(geo, lcar)
    x = points[:, (0)]
    y = points[:, (1)]
    triang = matplotlib.tri.Triangulation(x, y, cells)
    plt.tripcolor(triang, f(points.T), shading='flat')
    plt.colorbar()
    plt.set_cmap('coolwarm')
    clim = plt.gci().get_clim()
    mx = max(abs(clim[0]), abs(clim[1]))
    plt.clim(-mx, mx)
    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
