_own_group(true),_interpolation_matrix(0), _locator(0),
_source_field(0),_own_source_field(false),
_target_field(0),_own_target_field(false),
_own_group(true),_interpolation_matrix(0), _locator(0),
_source_field(0),_own_source_field(false),
_target_field(0),_own_target_field(false),