def METHOD_NAME(mtx, eps=None, color='b', **kwargs):
    """
    Show sparsity structure of a `scipy.sparse` matrix.
    """
    aux = mtx.tocoo()
    ij, val = nm.concatenate((aux.row[:,nm.newaxis],
                              aux.col[:,nm.newaxis]), 1), aux.data
    n_item = aux.getnnz()
    n_row, n_col = aux.shape
    if eps is not None:
        output('using eps =', eps)
        ij = nm.compress(nm.absolute(val) > eps, ij, 0)
        n_item = ij.shape[0]
    else:
        output('showing all')
    output('n_item:', n_item)
    if n_item:
        args = {'marker' : '.'}
        args.update(kwargs)
        plt.plot(ij[:,1], ij[:,0], color, linestyle='None', **args)
    plt.axis('image')
    plt.axis([-0.5, n_row+0.5, -0.5, n_col+0.5])
    plt.xlabel(r'%d x %d: %d nnz, %.2f%% fill'
               % (n_row, n_col, n_item, 100. * n_item /
                  (float(n_row) * float(n_col))))
    ax = plt.gca()
    ax.set_ylim(ax.get_ylim()[::-1])