def _read_complex_double(fid, tag, shape, rlims):
    # data gets stored twice as large
    if shape is not None:
        shape = (shape[0], shape[1] * 2)
    d = _fromstring_rows(fid, tag.size, dtype=">f8", shape=shape, rlims=rlims)
    d = d[::2] + 1j * d[1::2]
    return d
@todo: docstring
dataset/ETHPy150Open mne-tools/mne-python/mne/io/tag.py/_read_complex_double--crossover with--dataset/ETHPy150Open sahana/eden/modules/s3db/survey.py/survey_MatrixElement.joined