def plot_2d_contour(surf_file, surf_name='train_loss', vmin=0.1, vmax=10, vlevel=0.5, show=False):
    """Plot 2D contour map and 3D surface."""

    f = h5py.File(surf_file, 'r')
    x = np.array(f['xcoordinates'][:])
    y = np.array(f['ycoordinates'][:])
    X, Y = np.meshgrid(x, y)

    if surf_name in f.keys():
        Z = np.array(f[surf_name][:])
    elif surf_name == 'train_err' or surf_name == 'test_err' :
        Z = 100 - np.array(f[surf_name][:])
    else:
        print ('%s is not found in %s' % (surf_name, surf_file))

    print('------------------------------------------------------------------')
    print('plot_2d_contour')
    print('------------------------------------------------------------------')
    print("loading surface file: " + surf_file)
    print('len(xcoordinates): %d   len(ycoordinates): %d' % (len(x), len(y)))
    print('max(%s) = %f \t min(%s) = %f' % (surf_name, np.max(Z), surf_name, np.min(Z)))
    print(Z)

    if (len(x) <= 1 or len(y) <= 1):
        print('The length of coordinates is not enough for plotting contours')
        return

    # --------------------------------------------------------------------
    # Plot 2D contours
    # --------------------------------------------------------------------
    fig = plt.figure()
    CS = plt.contour(X, Y, Z, cmap='summer', levels=np.arange(vmin, vmax, vlevel))
    plt.clabel(CS, inline=1, fontsize=8)
    fig.savefig(surf_file + '_' + surf_name + '_2dcontour' + '.pdf', dpi=300,
                bbox_inches='tight', format='pdf')

    fig = plt.figure()
    print(surf_file + '_' + surf_name + '_2dcontourf' + '.pdf')
    CS = plt.contourf(X, Y, Z, cmap='summer', levels=np.arange(vmin, vmax, vlevel))
    fig.savefig(surf_file + '_' + surf_name + '_2dcontourf' + '.pdf', dpi=300,
                bbox_inches='tight', format='pdf')

    # --------------------------------------------------------------------
    # Plot 2D heatmaps
    # --------------------------------------------------------------------
    fig = plt.figure()
    sns_plot = sns.heatmap(Z, cmap='viridis', cbar=True, vmin=vmin, vmax=vmax,
                           xticklabels=False, yticklabels=False)
    sns_plot.invert_yaxis()
    sns_plot.get_figure().savefig(surf_file + '_' + surf_name + '_2dheat.pdf',
                                  dpi=300, bbox_inches='tight', format='pdf')

    # --------------------------------------------------------------------
    # Plot 3D surface
    # --------------------------------------------------------------------
    fig = plt.figure()
    ax = Axes3D(fig)
    surf = ax.plot_surface(X, Y, Z, cmap=cm.coolwarm, linewidth=0, antialiased=False)
    fig.colorbar(surf, shrink=0.5, aspect=5)
    fig.savefig(surf_file + '_' + surf_name + '_3dsurface.pdf', dpi=300,
                bbox_inches='tight', format='pdf')

    f.close()
    if show: plt.show()