def test_modify_view_component(matrix_type, mapping_name):
    adata = ad.AnnData(
        np.zeros((10, 10)),
        **{mapping_name: dict(m=matrix_type(asarray(sparse.random(10, 10))))},
    )
    init_hash = joblib.hash(adata)

    subset = adata[:5, :][:, :5]
    assert subset.is_view
    m = getattr(subset, mapping_name)["m"]
    m[0, 0] = 100
    assert not subset.is_view
    assert getattr(subset, mapping_name)["m"][0, 0] == 100

    assert init_hash == joblib.hash(adata)
def airgap_fft(airgap, bmin=1e-2, ax=0):
    """plot airgap harmonics"""
    unit = 'T'
    if ax == 0:
        ax = plt.gca()
    ax.set_title('Airgap Flux Density Harmonics / {}'.format(unit))
    ax.grid(True)
    order, fluxdens = np.array([(n, b) for n, b in zip(airgap['nue'],
                                                       airgap['B_nue']) if b > bmin]).T
    try:
        markerline1, stemlines1, _ = ax.stem(order, fluxdens, '-.', basefmt=" ",
                                             use_line_collection=True)
        ax.set_xticks(order)
    except ValueError:  # empty sequence
        pass