Method SolveLinearSystemBanded

src/LNLib/Mathematics/Utils/MathUtils.cpp:290–343

    return result;
}
bool LNLib::MathUtils::SolveLinearSystemBanded(int matrixDimension, const std::vector<std::vector<double>>& matrix, int bandwidth, const std::vector<std::vector<double>>& right, std::vector<std::vector<double>>& result)
{
    int sbw = bandwidth / 2;
    int n = matrixDimension;

    Eigen::SparseMatrix<double> A(n, n);
    std::vector<Eigen::Triplet<double>> triplets;
    triplets.reserve(n * bandwidth);

    for (int i = 0; i < n; i++) 
    {
        for (int k = 0; k < bandwidth; k++) 
        {
            int j = i - sbw + k;
            if (j >= 0 && j < n) 
            {
                double value = matrix[i][k];
                if (value != 0.0)
                {
                    triplets.push_back(Eigen::Triplet<double>(i, j, value));
                }
            }
        }
    }
    A.setFromTriplets(triplets.begin(), triplets.end());

    Eigen::SparseLU<Eigen::SparseMatrix<double>> solver;
    solver.analyzePattern(A);
    solver.factorize(A);

    if (solver.info() != Eigen::Success) {
        return false;
    }

    for (int k = 0; k < right[0].size(); k++)
    {
        Eigen::VectorXd rhs(n), solution(n);
        for (int i = 0; i < n; i++)
        {
            rhs(i) = right[i][k];
        }
        solution = solver.solve(rhs);
        if (solver.info() != Eigen::Success)
        {
            return false;
            break;
        }
        for (int i = 0; i < n; i++)
        {
            result[i][k] = solution(i);
        }
    }
    return true;
}