def test_set_subset_obsm(adata, subset_func):
    init_hash = joblib.hash(adata)
    orig_obsm_val = adata.obsm["o"].copy()

    while True:
        subset_idx = slice_subset(adata.obs_names)
        if len(adata[subset_idx, :]) > 2:
            break
    subset = adata[subset_idx, :]

    internal_idx = _normalize_index(
        subset_func(np.arange(subset.obsm["o"].shape[0])), subset.obs_names
    )

    assert subset.is_view
    subset.obsm["o"][internal_idx] = 1
    assert not subset.is_view
    assert np.all(adata.obsm["o"] == orig_obsm_val)

    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