Function _regularize

mne/preprocessing/maxwell.py:1390–1421

Regularize a decomposition matrix.

(
    regularize, exp, S_decomp, mag_or_fine, extended_remove, t, verbose=None
)

@verbose
def _regularize(
    regularize, exp, S_decomp, mag_or_fine, extended_remove, t, verbose=None
):
    """Regularize a decomposition matrix."""
    # ALWAYS regularize the out components according to norm, since
    # gradiometer-only setups (e.g., KIT) can have zero first-order
    # (homogeneous field) components
    int_order, ext_order = exp["int_order"], exp["ext_order"]
    n_in = _get_n_moments(int_order)
    n_out = S_decomp.shape[1] - n_in
    t_str = f"{t:8.3f}"
    if regularize is not None:  # regularize='in'
        in_removes, out_removes = _regularize_in(
            int_order, ext_order, S_decomp, mag_or_fine, extended_remove
        )
    else:
        in_removes = []
        out_removes = _regularize_out(
            int_order, ext_order, mag_or_fine, extended_remove
        )
    reg_in_moments = np.setdiff1d(np.arange(n_in), in_removes)
    reg_out_moments = np.setdiff1d(np.arange(n_in, S_decomp.shape[1]), out_removes)
    n_use_in = len(reg_in_moments)
    n_use_out = len(reg_out_moments)
    reg_moments = np.concatenate((reg_in_moments, reg_out_moments))
    S_decomp = S_decomp.take(reg_moments, axis=1)
    if regularize is not None or n_use_out != n_out:
        logger.info(
            f"        Using {n_use_in + n_use_out}/{n_in + n_out} harmonic components "
            f"for {t_str}  ({n_use_in}/{n_in} in, {n_use_out}/{n_out} out)"
        )
    return S_decomp, reg_moments, n_use_in


@verbose