template<class Ma, class Mc> struct create_preconditioner {
	static Mc create_preconditioner<Ma, Mc>::create(const Ma&A, const iterate_method& method, const Mc& conditioner) {
		if (method == ITERATE_OWN) return conditioner ;
		Mc ret(A.size1(),A.size2()) ;
		typename Ma::const_iterator it(A.begin1()) ;
		switch(method) {
			case ITERATE_RUMP:
				for(;it!=A.end1();++it) {
					ret(it.index1(),it.index2()) = *it.center();
				}
				break ;
			case ITERATE_JACOBI:
				for(;it!=A.end1();++it) {
					if (it.index1() == it.index2()) ret(it.index1(),it.index2()) = *it.center();
				}
				break ;
			case ITERATE_GAUSS_LOWER:
				for(;it!=A.end1();++it) {
					if (it.index1() >= it.index2()) ret(it.index1(),it.index2()) = *it.center();
				}
				break ;
			case ITERATE_GAUSS_UPPER:
				for(;it!=A.end1();++it) {
					if (it.index1() <= it.index2()) ret(it.index1(),it.index2()) = *it.center();
				}
				break ;
			default:
				throw runtime_error("unknown iterate method") ;
		}
		return ret ;
	}
} ;

template<class M> struct create_preconditioner<M, M> {
	static M create(const M&A, const iterate_method& method, const M& conditioner) {
		if (method == ITERATE_OWN) return conditioner ;
		M ret(A.size1(),A.size2()) ;
		typename M::const_iterator it(A.begin1()) ;
		switch(method) {
			case ITERATE_RUMP:
				for(;it!=A.end1();++it) {
					ret(it.index1(),it.index2()) = *it;
				}
				break ;
			case ITERATE_JACOBI:
				for(;it!=A.end1();++it) {
					if (it.index1() == it.index2()) ret(it.index1(),it.index2()) = *it;
				}
				break ;
			case ITERATE_GAUSS_LOWER:
				for(;it!=A.end1();++it) {
					if (it.index1() >= it.index2()) ret(it.index1(),it.index2()) = *it;
				}
				break ;
			case ITERATE_GAUSS_UPPER:
				for(;it!=A.end1();++it) {
					if (it.index1() <= it.index2()) ret(it.index1(),it.index2()) = *it;
				}
				break ;
			default:
				throw runtime_error("unknown iterate method") ;
		}
		return ret ;
	}
} ;