Function convert_forward_solution

mne/forward/forward.py:718–854

Convert forward solution between different source orientations. Parameters ---------- fwd : Forward The forward solution to modify. surf_ori : bool, optional (default False) Use surface-based source coordinate system? Note that force_fixed=True implies surf_o

(
    fwd, surf_ori=False, force_fixed=False, copy=True, use_cps=True, *, verbose=None
)

@verbose
def convert_forward_solution(
    fwd, surf_ori=False, force_fixed=False, copy=True, use_cps=True, *, verbose=None
):
    """Convert forward solution between different source orientations.

    Parameters
    ----------
    fwd : Forward
        The forward solution to modify.
    surf_ori : bool, optional (default False)
        Use surface-based source coordinate system? Note that force_fixed=True
        implies surf_ori=True.
    force_fixed : bool, optional (default False)
        If True, force fixed source orientation mode.
    copy : bool
        Whether to return a new instance or modify in place.
    %(use_cps)s
    %(verbose)s

    Returns
    -------
    fwd : Forward
        The modified forward solution.
    """
    fwd = fwd.copy() if copy else fwd

    if force_fixed is True:
        surf_ori = True

    if any([src["type"] == "vol" for src in fwd["src"]]) and force_fixed:
        raise ValueError(
            "Forward operator was generated with sources from a "
            "volume source space. Conversion to fixed orientation is not "
            "possible. Consider using a discrete source space if you have "
            "meaningful normal orientations."
        )

    if surf_ori and use_cps:
        if any(s.get("patch_inds") is not None for s in fwd["src"]):
            logger.info(
                "    Average patch normals will be employed in "
                "the rotation to the local surface coordinates.."
                ".."
            )
        else:
            use_cps = False
            logger.info(
                "    No patch info available. The standard source "
                "space normals will be employed in the rotation "
                "to the local surface coordinates...."
            )

    # We need to change these entries (only):
    # 1. source_nn
    # 2. sol['data']
    # 3. sol['ncol']
    # 4. sol_grad['data']
    # 5. sol_grad['ncol']