orbslam编译错误error: static assertion failed

Ubuntu16.04后编译报错，提示：

/usr/local/include/eigen3/Eigen/src/Core/util/StaticAssert.h:32:40: error: static assertion failed: YOU_MIXED_DIFFERENT_NUMERIC_TYPES__YOU_NEED_TO_USE_THE_CAST_METHOD_OF_MATRIXBASE_TO_CAST_NUMERIC_TYPES_EXPLICITLY
     #define EIGEN_STATIC_ASSERT(X,MSG) static_assert(X,#MSG);

问题原因：Eigen3的bug

解决方法：打开Thirdparty/g2o/g2o/solvers/linear_solver_eigen.h，将以下代码

typedef Eigen::PermutationMatrix<Eigen::Dynamic, Eigen::Dynamic, SparseMatrix::Index> PermutationMatrix;

替换为

typedef Eigen::PermutationMatrix<Eigen::Dynamic, Eigen::Dynamic, int> PermutationMatrix;