Function isApproxCPTP

tests/utils/linalg.cpp:577–588

bool isApproxCPTP(vector<qmatrix> matrices) {
    DEMAND( matrices.size() >= 1 );

    size_t dim = matrices[0].size();
    qmatrix id = getIdentityMatrix(dim);
    qmatrix sum = getZeroMatrix(dim);

    for (auto& m : matrices)
        sum += getConjugateTranspose(m) * m;

    return doMatricesAgree(sum, id);
}