Find all matches and generate a position group for each match.

def _match(self):
        """Find all matches and generate a position group for each match."""
        #disable optimized matching
        optimized_rows = None
        optimized_columns = None
        for match in self.__match_rows(optimized_rows):
            #match in rows
            yield match
        for match in self.__match_rows(optimized_columns,
                                       transpose=True):
            #match in columns and transpose coordinates
            yield match