Function _create_eeg_el

mne/forward/_make_forward.py:210–244

Create an electrode definition, transform coords if necessary.

(ch, t=None)

def _create_eeg_el(ch, t=None):
    """Create an electrode definition, transform coords if necessary."""
    if ch["kind"] != FIFF.FIFFV_EEG_CH:
        raise RuntimeError(
            f"{ch['ch_name']} is not an EEG channel. Cannot create an electrode "
            "definition."
        )
    if t is None:
        t = Transform("head", "head")  # identity, no change
    if t.from_str != "head":
        raise RuntimeError("Inappropriate coordinate transformation")

    r0ex = _loc_to_eeg_loc(ch["loc"])
    if r0ex.shape[1] == 1:  # no reference
        w = np.array([1.0])
    else:  # has reference
        w = np.array([1.0, -1.0])

    # Optional coordinate transformation
    r0ex = apply_trans(t["trans"], r0ex.T)

    # The electrode location
    cosmag = r0ex.copy()
    _normalize_vectors(cosmag)
    res = dict(
        chname=ch["ch_name"],
        coil_class=FWD.COILC_EEG,
        w=w,
        accuracy=_accuracy_dict["normal"],
        type=ch["coil_type"],
        coord_frame=t["to"],
        rmag=r0ex,
        cosmag=cosmag,
    )
    return res


def _create_meg_coils(chs, acc, t=None, coilset=None, do_es=False):