CrsMatrix: A cross B added

	if (nrow_B != 0) B.checkValidity();

}

//-------

/** If order==false then

		creates C such that C_{i1+j1*nout,i2+j2*nout)=A(j1,j2)B_{i1,i2}

		if order==true then

		creates C such that C_{i1+j1*na,i2+j2*na)=A(i1,i2)B_{j1,j2}

		where na=rank(A) and nout = rank(B)

	  */

template<typename T,typename VectorLikeType>

typename EnableIf<IsVectorLike<VectorLikeType>::True &&

Loki::TypeTraits<typename VectorLikeType::value_type>::isFloat,

void>::Type

externalProduct(CrsMatrix<T>& C,

                const CrsMatrix<T>& A,

                const CrsMatrix<T>& B,

                const VectorLikeType& signs,

                bool order,

                const PsimagLite::Vector<SizeType>::Type& permutationFull)

{

    const SizeType nfull = permutationFull.size();

    Vector<SizeType>::Type perm(nfull);

    for (SizeType i = 0; i < nfull; ++i) perm[permutationFull[i]] = i;

    const SizeType nout = B.rows();

    const SizeType na = A.rows();

    const SizeType noutOrNa = (!order) ? nout : na;

    const CrsMatrix<T>& AorB = (!order) ? A : B;

    const CrsMatrix<T>& BorA = (!order) ? B : A;

    assert(A.rows() == A.cols());

    assert(B.rows() == B.cols());

    assert(nout*na == nfull);

    assert(signs.size() == noutOrNa);

    C.resize(nfull, nfull);

    SizeType counter = 0;

    for (SizeType i = 0; i < nfull; ++i) {

        C.setRow(i, counter);

        const SizeType ind = perm[i];

        div_t q = div(ind, noutOrNa);

        for (int k1 = BorA.getRowPtr(q.rem); k1 < BorA.getRowPtr(q.rem + 1); ++k1) {

            const SizeType col1 = BorA.getCol(k1);

            for (int k2 = AorB.getRowPtr(q.quot); k2 < AorB.getRowPtr(q.quot + 1); ++k2) {

                const SizeType col2 = AorB.getCol(k2);

                SizeType j = permutationFull[col1 + col2*noutOrNa];

                C.pushCol(j);

                C.pushValue(BorA.getValue(k1) * AorB.getValue(k2) * signs[q.rem]);

                ++counter;

            }

        }

    }

    C.setRow(nfull, counter);

    C.checkValidity();

}

template<typename T>

void printFullMatrix(const CrsMatrix<T>& s,