Method coeff

Eigen/src/Core/TriangularMatrix.h:75–76

    }

    EIGEN_DEVICE_FUNC
    inline Scalar coeff(Index row, Index col) const  { return derived().coeff(row,col); }
    EIGEN_DEVICE_FUNC
    inline Scalar& coeffRef(Index row, Index col) { return derived().coeffRef(row,col); }