在c ++中使用Fenics进行简单的网格生成，奇怪的错误？

Question

我是Fenics的新手，我只想创建一个带孔的多边形网格。我写了：

// Vector of points
    std::vector<Point> pts;
    pts.push_back(Point(  0.0,   0.0));
    pts.push_back(Point(  4.0,   0.0));
    pts.push_back(Point(  4.0,   8.0));
    pts.push_back(Point(  0.0,   8.0));
    pts.push_back(Point(  0.0,   8.0 / 2 + 0.5));
    pts.push_back(Point(  1.0,   8.0 / 2 + 0.5));
    pts.push_back(Point(  2.0,   8.0 / 4      ));
    pts.push_back(Point(  1.0,   8.0 / 2 - 0.5));
    pts.push_back(Point(  0.0,   8.0 / 2 - 0.5));

    // Polygone
    mshr::Polygon polyline(pts);

    // Hole
    mshr::Circle circle(Point(2.0, 7.0), 0.3);

    // Difference: IT IS A SHARED POINTER
    auto difference = polyline - circle;

    // Create a simple mesh
    Mesh mesh;

    mshr::CSGCGALMeshGenerator2D generator;

    // Mesh it!
    generator.generate(*difference, mesh);

但我一直收到此错误消息，无法生成可执行文件：

  

扫描目标demo_poisson [50％]构建CXX的依赖关系   object CMakeFiles / demo_poisson.dir / main.cpp.o [100％]链接CXX   可执行的demo_poisson CMakeFiles / demo_poisson.dir / main.cpp.o:In   函数mshr::CSGDifference::~CSGDifference()': /home/fenics/local/include/mshr/CSGOperators.h:67: undefined reference to vtable for mshr :: CSGDifference'   CMakeFiles / demo_poisson.dir / main.cpp.o：在函数中   `MSHR :: CSGOperator ::〜CSGOperator（）'：...............................

任何人都知道这里发生了什么？任何帮助表示赞赏，提前谢谢。