Function _read_one

mne/forward/forward.py:326–372

Read all interesting stuff for one forward solution.

(fid, node)

def _read_one(fid, node):
    """Read all interesting stuff for one forward solution."""
    # This function assumes the fid is open as a context manager
    if node is None:
        return None

    one = Forward()
    one["source_ori"] = _get_tag_int(
        fid, node, "Source orientation", FIFF.FIFF_MNE_SOURCE_ORIENTATION
    )
    one["coord_frame"] = _get_tag_int(
        fid, node, "Coordinate frame", FIFF.FIFF_MNE_COORD_FRAME
    )
    one["nsource"] = _get_tag_int(
        fid, node, "Number of sources", FIFF.FIFF_MNE_SOURCE_SPACE_NPOINTS
    )
    one["nchan"] = _get_tag_int(fid, node, "Number of channels", FIFF.FIFF_NCHAN)
    try:
        one["sol"] = _read_named_matrix(
            fid, node, FIFF.FIFF_MNE_FORWARD_SOLUTION, transpose=True
        )
        one["_orig_sol"] = one["sol"]["data"].copy()
    except Exception:
        logger.error("Forward solution data not found")
        raise

    try:
        fwd_type = FIFF.FIFF_MNE_FORWARD_SOLUTION_GRAD
        one["sol_grad"] = _read_named_matrix(fid, node, fwd_type, transpose=True)
        one["_orig_sol_grad"] = one["sol_grad"]["data"].copy()
    except Exception:
        one["sol_grad"] = None

    if one["sol"]["data"].shape[0] != one["nchan"] or (
        one["sol"]["data"].shape[1] != one["nsource"]
        and one["sol"]["data"].shape[1] != 3 * one["nsource"]
    ):
        raise ValueError("Forward solution matrix has wrong dimensions")

    if one["sol_grad"] is not None:
        if one["sol_grad"]["data"].shape[0] != one["nchan"] or (
            one["sol_grad"]["data"].shape[1] != 3 * one["nsource"]
            and one["sol_grad"]["data"].shape[1] != 3 * 3 * one["nsource"]
        ):
            raise ValueError("Forward solution gradient matrix has wrong dimensions")

    return one


@fill_doc