Write configurations to a Syscal ascii file that can be read by the
    Electre Pro program.

    Parameters
    ----------
    filename: string
        output filename
    configs: numpy.ndarray
        Nx4 array with measurement configurations A-B-M-N

def syscal_save_to_config_txt(filename, configs, spacing=1):
    """Write configurations to a Syscal ascii file that can be read by the
    Electre Pro program.

    Parameters
    ----------
    filename: string
        output filename
    configs: numpy.ndarray
        Nx4 array with measurement configurations A-B-M-N

    """
    print('Number of measurements: ', configs.shape[0])
    number_of_electrodes = configs.max().astype(int)

    with open(filename, 'w') as fid:
        _syscal_write_electrode_coords(fid, spacing, number_of_electrodes)
        _syscal_write_quadpoles(fid, configs.astype(int))