g2o优化调试报错：‘Sophus::SE3::SE3()’未定义的引用

报错现象：
CMakeFiles/visualOdometry.dir/visualOdometry.cpp.o：在函数‘main’中：
visualOdometry.cpp:(.text.startup+0x7a)：对‘Sophus::SE3::SE3()’未定义的引用
visualOdometry.cpp:(.text.startup+0x1528)：对‘Sophus::SO3::SO3(double, double, double)’未定义的引用
visualOdometry.cpp:(.text.startup+0x1542)：对‘Sophus::SE3::SE3(Sophus::SO3 const&, Eigen::Matrix const&)’未定义的引用
visualOdometry.cpp:(.text.startup+0x1555)：对‘Sophus::SE3::operator=(Sophus::SE3 const&)’未定义的引用
…/…/lib/libslambase.a(slamBase.cpp.o)：在函数‘estimateMotion(FRAME&, FRAME&, CAMERA_INTRINSIC_PARAMETERS&)’中：
slamBase.cpp:(.text+0xc89)：对‘Sophus::SE3::SE3()’未定义的引用
collect2: error: ld returned 1 exit status
src/CMakeFiles/visualOdometry.dir/build.make:271: recipe for target ‘…/bin/visualOdometry’ failed
make[2]: *** […/bin/visualOdometry] Error 1
CMakeFiles/Makefile2:87: recipe for target ‘src/CMakeFiles/visualOdometry.dir/all’ failed
make[1]: *** [src/CMakeFiles/visualOdometry.dir/all] Error 2
Makefile:83: recipe for target ‘all’ failed
make: *** [all] Error 2

解决办法：
原因：没有连接到sohpus库，检查cmakelists

添加如下：
find_package( Sophus REQUIRED )
include_directories( ${Sophus_INCLUDE_DIRS} )

add_executable( useSophus useSophus.cpp )
target_link_libraries( useSophus ${Sophus_LIBRARIES} )