qt Aborted (core dumped)

and also:


    '''
    ====================
    3D plots as subplots
    ====================

    Demonstrate including 3D plots as subplots.
    '''

    import matplotlib.pyplot as plt
    from mpl_toolkits.mplot3d.axes3d import Axes3D, get_test_data
    from matplotlib import cm
    import numpy as np


    # set up a figure twice as wide as it is tall
    fig = plt.figure(figsize=plt.figaspect(0.5))

    #===============
    #  First subplot
    #===============
    # set up the axes for the first plot
    ax = fig.add_subplot(1, 2, 1, projection='3d')

    # plot a 3D surface like in the example mplot3d/surface3d_demo
    X = np.arange(-5, 5, 0.25)
    Y = np.arange(-5, 5, 0.25)
    X, Y = np.meshgrid(X, Y)
    R = np.sqrt(X**2 + Y**2)
    Z = np.sin(R)
    surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=cm.coolwarm,
                           linewidth=0, antialiased=False)
    ax.set_zlim(-1.01, 1.01)
    fig.colorbar(surf, shrink=0.5, aspect=10)

    #===============
    # Second subplot
    #===============
    # set up the axes for the second plot
    ax = fig.add_subplot(1, 2, 2, projection='3d')

    # plot a 3D wireframe like in the example mplot3d/wire3d_demo
    X, Y, Z = get_test_data(0.05)
    ax.plot_wireframe(X, Y, Z, rstride=10, cstride=10)

    plt.show()


and when I run it I get:

    $ python test_qt.py
    qt.qpa.xcb: could not connect to display desktop:0
    qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
    This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

    Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, webgl, xcb.

    Aborted (core dumped)
    18790/31772MB(vision)