eigen库位置，常发现cmake找不到,修改cmake，如下链接
https://github.com/tu-darmstadt-ros-pkg/hector_slam/commit/d9e44fb85087cdf40d4fe702082701b2882eefea
| find_package(Eigen3) | |||
| if(NOT EIGEN3_FOUND) | |||
| # Fallback to cmake_modules | |||
| find_package(cmake_modules REQUIRED) | |||
| find_package(Eigen REQUIRED) | |||
| set(EIGEN3_INCLUDE_DIRS ${EIGEN_INCLUDE_DIRS}) | |||
| set(EIGEN3_LIBRARIES ${EIGEN_LIBRARIES}) # Not strictly necessary as Eigen is head only | |||
| # Possibly map additional variables to the EIGEN3_ prefix. | |||
| else() | |||
| set(EIGEN3_INCLUDE_DIRS ${EIGEN3_INCLUDE_DIR}) | |||
| endif() | |||
原文：https://www.cnblogs.com/Baron-Lu/p/11431274.html