在编译ORBSLAM时出现的问题如下：
Scanning dependencies of target ORB_SLAM2-map
[ 8%] Building CXX object CMakeFiles/ORB_SLAM2-map.dir/src/Tracking.cc.o
[ 12%] Building CXX object CMakeFiles/ORB_SLAM2-map.dir/src/LocalMapping.cc.o
[ 16%] Building CXX object CMakeFiles/ORB_SLAM2-map.dir/src/LoopClosing.cc.o
[ 20%] Building CXX object CMakeFiles/ORB_SLAM2-map.dir/src/ORBextractor.cc.o
[ 25%] Building CXX object CMakeFiles/ORB_SLAM2-map.dir/src/ORBmatcher.cc.o
[ 29%] Building CXX object CMakeFiles/ORB_SLAM2-map.dir/src/FrameDrawer.cc.o
[ 33%] Building CXX object CMakeFiles/ORB_SLAM2-map.dir/src/Converter.cc.o
[ 37%] Building CXX object CMakeFiles/ORB_SLAM2-map.dir/src/MapPoint.cc.o
/home/pjz/zhushi/ORB_SLAM2-map/src/MapPoint.cc: In instantiation of ‘void ORB_SLAM2::MapPoint::load(Archive&, unsigned int) [with Archive = boost::archive::binary_oarchive]’:
/home/pjz/zhushi/ORB_SLAM2-map/src/MapPoint.cc:223:23: required from here
/home/pjz/zhushi/ORB_SLAM2-map/src/MapPoint.cc:176:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < nItems; ++i) {
^
/home/pjz/zhushi/ORB_SLAM2-map/src/MapPoint.cc: In instantiation of ‘void ORB_SLAM2::MapPoint::load(Archive&, unsigned int) [with Archive = boost::archive::binary_iarchive]’:
/home/pjz/zhushi/ORB_SLAM2-map/src/MapPoint.cc:226:23: required from here
/home/pjz/zhushi/ORB_SLAM2-map/src/MapPoint.cc:176:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
[ 41%] Building CXX object CMakeFiles/ORB_SLAM2-map.dir/src/KeyFrame.cc.o
[ 45%] Building CXX object CMakeFiles/ORB_SLAM2-map.dir/src/Map.cc.o
[ 50%] Building CXX object CMakeFiles/ORB_SLAM2-map.dir/src/MapDrawer.cc.o
[ 54%] Building CXX object CMakeFiles/ORB_SLAM2-map.dir/src/Optimizer.cc.o
In file included from /usr/include/eigen3/Eigen/Core:297:0,
from /home/pjz/zhushi/ORB_SLAM2-map/Thirdparty/g2o/g2o/types/../core/jacobian_workspace.h:30,
from /home/pjz/zhushi/ORB_SLAM2-map/Thirdparty/g2o/g2o/types/../core/optimizable_graph.h:41,
from /home/pjz/zhushi/ORB_SLAM2-map/Thirdparty/g2o/g2o/types/../core/base_vertex.h:30,
from /home/pjz/zhushi/ORB_SLAM2-map/Thirdparty/g2o/g2o/types/types_seven_dof_expmap.h:34,
from /home/pjz/zhushi/ORB_SLAM2-map/include/LoopClosing.h:34,
from /home/pjz/zhushi/ORB_SLAM2-map/include/Optimizer.h:27,
from /home/pjz/zhushi/ORB_SLAM2-map/src/Optimizer.cc:21:
/usr/include/eigen3/Eigen/src/Core/AssignEvaluator.h: In instantiation of ‘void Eigen::internal::call_assignment_no_alias(Dst&, const Src&, const Func&) [with Dst = Eigen::Matrix<int, -1, 1>; Src = Eigen::Matrix<long int, -1, 1, 0, -1, 1>; Func = Eigen::internal::assign_op<int>]’:
/usr/include/eigen3/Eigen/src/Core/AssignEvaluator.h:712:27: required from ‘void Eigen::internal::call_assignment(Dst&, const Src&, const Func&, typename Eigen::internal::enable_if<(! Eigen::internal::evaluator_assume_aliasing<Src>::value), void*>::type) [with Dst = Eigen::Matrix<int, -1, 1>; Src = Eigen::Matrix<long int, -1, 1, 0, -1, 1>; Func = Eigen::internal::assign_op<int>; typename Eigen::internal::enable_if<(! Eigen::internal::evaluator_assume_aliasing<Src>::value), void*>::type = void*]’
/usr/include/eigen3/Eigen/src/Core/AssignEvaluator.h:693:18: required from ‘void Eigen::internal::call_assignment(Dst&, const Src&) [with Dst = Eigen::Matrix<int, -1, 1>; Src = Eigen::Matrix<long int, -1, 1, 0, -1, 1>]’
/usr/include/eigen3/Eigen/src/Core/PlainObjectBase.h:682:32: required from ‘Derived& Eigen::PlainObjectBase<Derived>::_set(const Eigen::DenseBase<OtherDerived>&) [with OtherDerived = Eigen::Matrix<long int, -1, 1, 0, -1, 1>; Derived = Eigen::Matrix<int, -1, 1>]’
/usr/include/eigen3/Eigen/src/Core/Matrix.h:225:24: required from ‘Eigen::Matrix<_Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols>& Eigen::Matrix<_Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols>::operator=(const Eigen::DenseBase<OtherDerived>&) [with OtherDerived = Eigen::Matrix<long int, -1, 1, 0, -1, 1>; _Scalar = int; int _Rows = -1; int _Cols = 1; int _Options = 0; int _MaxRows = -1; int _MaxCols = 1]’
/usr/include/eigen3/Eigen/src/Core/PermutationMatrix.h:367:17: required from ‘Eigen::PermutationMatrix<SizeAtCompileTime, MaxSizeAtCompileTime, IndexType>& Eigen::PermutationMatrix<SizeAtCompileTime, MaxSizeAtCompileTime, IndexType>::operator=(const Eigen::PermutationBase<OtherDerived>&) [with Other = Eigen::PermutationMatrix<-1, -1, long int>; int SizeAtCompileTime = -1; int MaxSizeAtCompileTime = -1; _StorageIndex = int]’
/home/pjz/zhushi/ORB_SLAM2-map/Thirdparty/g2o/g2o/solvers/linear_solver_eigen.h:68:18: required from ‘void g2o::LinearSolverEigen<MatrixType>::CholeskyDecomposition::analyzePatternWithPermutation(g2o::LinearSolverEigen<MatrixType>::SparseMatrix&, const PermutationMatrix&) [with MatrixType = Eigen::Matrix<double, 7, 7, 0, 7, 7>; g2o::LinearSolverEigen<MatrixType>::SparseMatrix = Eigen::SparseMatrix<double, 0>; g2o::LinearSolverEigen<MatrixType>::PermutationMatrix = Eigen::PermutationMatrix<-1, -1, long int>]’
/home/pjz/zhushi/ORB_SLAM2-map/Thirdparty/g2o/g2o/solvers/linear_solver_eigen.h:195:9: required from ‘void g2o::LinearSolverEigen<MatrixType>::computeSymbolicDecomposition(const g2o::SparseBlockMatrix<MatrixType>&) [with MatrixType = Eigen::Matrix<double, 7, 7, 0, 7, 7>]’
/home/pjz/zhushi/ORB_SLAM2-map/Thirdparty/g2o/g2o/solvers/linear_solver_eigen.h:100:37: required from ‘bool g2o::LinearSolverEigen<MatrixType>::solve(const g2o::SparseBlockMatrix<MatrixType>&, double*, double*) [with MatrixType = Eigen::Matrix<double, 7, 7, 0, 7, 7>]’
/home/pjz/zhushi/ORB_SLAM2-map/src/Optimizer.cc:1262:1: required from here
/usr/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);
^
/usr/include/eigen3/Eigen/src/Core/util/XprHelper.h:707:3: note: in expansion of macro ‘EIGEN_STATIC_ASSERT’
EIGEN_STATIC_ASSERT((internal::functor_is_product_like<BINOP>::ret \
^
/usr/include/eigen3/Eigen/src/Core/AssignEvaluator.h:745:3: note: in expansion of macro ‘EIGEN_CHECK_BINARY_COMPATIBILIY’
EIGEN_CHECK_BINARY_COMPATIBILIY(Func,typename ActualDstTypeCleaned::Scalar,ty
^
CMakeFiles/ORB_SLAM2-map.dir/build.make:350: recipe for target 'CMakeFiles/ORB_SLAM2-map.dir/src/Optimizer.cc.o' failed
make[2]: *** [CMakeFiles/ORB_SLAM2-map.dir/src/Optimizer.cc.o] Error 1
CMakeFiles/Makefile2:67: recipe for target 'CMakeFiles/ORB_SLAM2-map.dir/all' failed
make[1]: *** [CMakeFiles/ORB_SLAM2-map.dir/all] Error 2
Makefile:83: recipe for target 'all' failed
make: *** [all] Error 2
解决办法如下：
打开Thirdparty/g2o/g2o/solvers/linear_solver_eigen.h
找到如下代码：
typedef Eigen::PermutationMatrix<Eigen::Dynamic, Eigen::Dynamic, SparseMatrix::Index> PermutationMatrix;把上边的代码改为如下：
typedef Eigen::PermutationMatrix<Eigen::Dynamic, Eigen::Dynamic, int> PermutationMatrix;
即把红色的部分改为int;
改完保存，重新编译g2o的共享库，然后在编译orbslam2，就ok啦。