def force_aspect(ax, aspect=1):
    im = ax.get_images()
    extent = im[0].get_extent()
    ax.set_aspect(abs((extent[1]-extent[0])/(extent[3]-extent[2]))/aspect)

def mpl_matshow(ax, data, shape):
    ax.matshow(data.reshape(shape, shape), cmap='hot', aspect='auto')
    ax.set_xticks([])
    ax.set_yticks([])
    force_aspect(ax)