cmake_mrpt_g2o_ceres - yuhannah/skills_map GitHub Wiki
MRPT 应用 CMake
编译及配置mrpt库的过程中，下载源码，新建build文件夹，cmake以及make的过程都执行顺利。
如何在工程中调用mrpt库呢？
(1)一种方法，将mrpt安装到系统中，make install命令，mrpt的库就安装到比如/usr 或/usr/local 中。直接调用。(未测试)
(2)另一种方法，用户提供MRPTConfig.cmake 文件路径，该文件在编译mrpt后生成，在/mrpt-1.5.6/build/下。意思是，在创建的工程中，在CMakeLists.txt文件中，添加include(/home/yu/mrpt-1.5.6/build/MRPTConfig.cmake REQUIRED)这句话，该文件指明了mrpt库在哪里。
摘自mrpt指导：
- 在 Linux/Windows 系统,需要用户提供 MRPTConfig.cmake 文件路径(在创建 MRPT库的过程中已经生成),有时候 CMake 会自动找到 MRPT 目录不需要用户提供路径。
- 在 Linux 中,如果 MRPT 已经安装在系统中(比如/usr 或/usr/local 或),cmake 会自动找到 MRPT 配置文件,不要额外操作。
g2o 和 ceres 应用 cmake
目标：
- 在源码库基础上，调用安装好的依赖库（
usr/include中），外部构建和编译，调用测试源码仿真 - 在源码库基础上，调用安装好的依赖库（
usr/include中），外部构建和编译（及安装），另外建立工程调用 g2o / ceres 编写测试程序 - 在源码库基础上，调用内部构建的依赖库，外部构建和编译，调用测试源码仿真
- 在源码库基础上，调用内部构建的依赖库，外部构建和编译（及安装），另外建立工程调用 g2o / ceres 编写测试程序
- 在源码库基础上，调用内部构建的依赖库，交叉编译
g2o 应用 cmake
测试 1
下载 g2o 源码库，安装依赖。在工程目录 g2o 下新建目录build，进入目录build，执行cmake ..命令：
-- The C compiler identification is GNU 5.4.0
-- The CXX compiler identification is GNU 5.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Compiling on Unix
-- Found CHOLMOD: /usr/include/suitesparse # 内部MESSAGE
-- Looking for sgemm_
-- Looking for sgemm_ - found
-- A library with BLAS API found. # MESSAGE
-- Looking for cheev_
-- Looking for cheev_ - found
-- A library with LAPACK API found. # MESSAGE
-- Found CHOLMOD and its dependencies # MESSAGE
-- Found CSPARSE: /usr/include/suitesparse # 内部MESSAGE
-- Found OpenGL: /usr/lib/x86_64-linux-gnu/libGL.so # 内部MESSAGE
-- Compiling with OpenGL support # MESSAGE
-- Found QGLVIEWER: /usr/include/QGLViewer # 内部MESSAGE
-- Compiling g2o apps # MESSAGE
-- Compiling g2o examples # MESSAGE
-- Compiling with GCC # MESSAGE
-- Found Eigen3: /usr/include/eigen3 (Required is at least version "2.91.0") # 内部MESSAGE
-- Generating position indpendent code for slam2d because Qt5 was built with -reduce-relocations
-- Configuring done
-- Generating done
-- Build files have been written to: /home/yu/sources/g2o/build # 编译结果目录
继续执行make命令，编译成功。生成的库在工程目录 g2o 下的目录 lib 中，生成的可执行文件在工程目录 g2o 下的目录 bin 中。
进入目录 g2o/bin，可以看到所有的可执行文件，执行./slam2d_g2o。
在窗口菜单栏点击File，添加原始 2d g2o数据集（数据集来自 openSlam-vertigo ），加载 manhattanOlson3500.g2o数据集，并选择 Optimize：
Graph loaded with 3500 vertices and 5598 measurments
graph is fixed by node 3499
iteration= 0 chi2= 8851.536592 time= 0.0369276 cumTime= 0.0369276 edges= 5598 schur= 0
iteration= 1 chi2= 189.465178 time= 0.00820572 cumTime= 0.0451333 edges= 5598 schur= 0
iteration= 2 chi2= 146.566132 time= 0.0068049 cumTime= 0.0519382 edges= 5598 schur= 0
iteration= 3 chi2= 146.076641 time= 0.00668695 cumTime= 0.0586251 edges= 5598 schur= 0
iteration= 4 chi2= 146.076613 time= 0.00656356 cumTime= 0.0651887 edges= 5598 schur= 0
iteration= 5 chi2= 146.076613 time= 0.00667749 cumTime= 0.0718662 edges= 5598 schur= 0
iteration= 6 chi2= 146.076613 time= 0.00651187 cumTime= 0.0783781 edges= 5598 schur= 0
iteration= 7 chi2= 146.076613 time= 0.00650471 cumTime= 0.0848828 edges= 5598 schur= 0
iteration= 8 chi2= 146.076613 time= 0.00652948 cumTime= 0.0914123 edges= 5598 schur= 0
iteration= 9 chi2= 146.076613 time= 0.00675476 cumTime= 0.098167 edges= 5598 schur= 0
测试 2
清除工程目录 g2o 下目录build的内容，进入目录build，执行cmake -DCMAKE_INSTALL_PREFIX=/home/yu/sources/g2o/install ..命令，将 g2o 安装到指定目录/home/yu/sources/g2o/install下。
-- The C compiler identification is GNU 5.4.0
-- The CXX compiler identification is GNU 5.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- CMAKE_RUNTIME_OUTPUT_DIRECTORY is /home/yu/sources/g2o/bin
-- CMAKE_LIBRARY_OUTPUT_DIRECTORY is /home/yu/sources/g2o/lib
-- CMAKE_INSTALL_PREFIX is /home/yu/sources/g2o/install # 自定义安装目录
-- Compiling on Unix
-- Found CHOLMOD: /usr/include/suitesparse
-- Looking for sgemm_
-- Looking for sgemm_ - found
-- A library with BLAS API found.
-- Looking for cheev_
-- Looking for cheev_ - found
-- A library with LAPACK API found.
-- Found CHOLMOD and its dependencies
-- Found CSPARSE: /usr/include/suitesparse
-- Found OpenGL: /usr/lib/x86_64-linux-gnu/libGL.so
-- Compiling with OpenGL support
-- Found QGLVIEWER: /usr/include/QGLViewer
-- Compiling g2o apps
-- Compiling g2o examples
-- Compiling with GCC
-- Found Eigen3: /usr/include/eigen3 (Required is at least version "2.91.0")
-- INCLUDES_DESTINATION is /home/yu/sources/g2o/install/include
-- G2O_CONFIG_INSTALL_DIR is lib/cmake/g2o
-- Generating position indpendent code for slam2d because Qt5 was built with -reduce-relocations
-- Configuring done
-- Generating done
-- Build files have been written to: /home/yu/sources/g2o/build
执行make和make install安装成功。
为了找到自定义安装路径中的 g2o 库，需要修改 g2o 库中原有的FindG2O.cmake文件：
# g2o的cmake_modules的FindG2O.cmake
find_path(G2O_INCLUDE_DIR g2o/core/base_vertex.h
...
/home/yu/sources/g2o/install/include # 添加自定义安装路径
)
find_library("${MYLIBRARY}_DEBUG"
NAMES "g2o_${MYLIBRARYNAME}_d"
PATHS
...
/home/yu/sources/g2o/install/lib # 添加自定义安装路径
)
...
在新的工程中的 CMakeLists.txt文件中添加 g2o 库的cmake modules 路径：
# testG2O的CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
project(testG2O)
set(CMAKE_CXX_STANDARD 11)
SET(CMAKE_MODULE_PATH /home/yu/sources/g2o/cmake_modules) # 添加 g2o 库的cmake_modeles路径
MESSAGE(STATUS "MODULE_PATH: " ${CMAKE_MODULE_PATH})
find_package(G2O REQUIRED)
MESSAGE(STATUS "G2O_INCLUDE_DIR is ${G2O_INCLUDE_DIR}") # 输出信息
MESSAGE(STATUS "G2O_STUFF_LIBRARY is ${G2O_STUFF_LIBRARY}")
MESSAGE(STATUS "G2O_CORE_LIBRARY is ${G2O_CORE_LIBRARY}")
MESSAGE(STATUS "G2O_CLI_LIBRARY is ${G2O_CLI_LIBRARY}")
MESSAGE(STATUS "G2O_SOLVER_CHOLMOD is ${G2O_SOLVER_CHOLMOD}")
IF(G2O_FOUND)
include_directories(${G2O_INCLUDE_DIR})
message(STATUS "G2O lib is found:" ${G2O_INCLUDE_DIR}) # 输出信息
ENDIF(G2O_FOUND)
find_package(Eigen3 REQUIRED)
find_package(CSparse REQUIRED)
#find_package(Cholmod REQUIRED)
include_directories(${CSPARSE_INCLUDE_DIR})
include_directories(${EIGEN3_INCLUDE_DIR})
add_executable(testG2O main.cpp)
SET(G2O_LIBS g2o_cli g2o_ext_freeglut_minimal g2o_simulator g2o_solver_slam2d_linear g2o_types_icp g2o_types_slam2d g2o_core g2o_interface g2o_solver_csparse g2o_solver_structure_only g2o_types_sba g2o_types_slam3d g2o_csparse_extension g2o_opengl_helper g2o_solver_dense g2o_stuff g2o_types_sclam2d g2o_parser g2o_solver_pcg g2o_types_data g2o_types_sim3 cxsparse )
target_link_libraries(testG2O ${G2O_LIBS})
构建，添加了部分输出信息：
-- The C compiler identification is GNU 5.4.0
-- The CXX compiler identification is GNU 5.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- MODULE_PATH: /home/yu/sources/g2o/cmake_modules
-- G2O_INCLUDE_DIR is /home/yu/sources/g2o/install/include
-- G2O_STUFF_LIBRARY is /home/yu/sources/g2o/install/lib/libg2o_stuff.so
-- G2O_CORE_LIBRARY is /home/yu/sources/g2o/install/lib/libg2o_core.so
-- G2O_CLI_LIBRARY is /home/yu/sources/g2o/install/lib/libg2o_cli.so
-- G2O_SOLVER_CHOLMOD is /home/yu/sources/g2o/install/lib/libg2o_solver_cholmod.so
-- G2O lib is found:/home/yu/sources/g2o/install/include # 找到g2o噢
-- Found Eigen3: /usr/include/eigen3 (Required is at least version "2.91.0")
-- Found CSPARSE: /usr/include/suitesparse
-- Configuring done
-- Generating done
-- Build files have been written to: /home/yu/CLionProjects/testG2O/build
但是在编译时还是出现找不到库的问题：
Scanning dependencies of target testG2O
[ 50%] Building CXX object CMakeFiles/testG2O.dir/main.cpp.o
[100%] Linking CXX executable testG2O
/usr/bin/ld: cannot find -lg2o_cli
/usr/bin/ld: cannot find -lg2o_ext_freeglut_minimal
/usr/bin/ld: cannot find -lg2o_simulator
/usr/bin/ld: cannot find -lg2o_solver_slam2d_linear
/usr/bin/ld: cannot find -lg2o_types_icp
/usr/bin/ld: cannot find -lg2o_types_slam2d
/usr/bin/ld: cannot find -lg2o_core
/usr/bin/ld: cannot find -lg2o_interface
/usr/bin/ld: cannot find -lg2o_solver_csparse
/usr/bin/ld: cannot find -lg2o_solver_structure_only
/usr/bin/ld: cannot find -lg2o_types_sba
/usr/bin/ld: cannot find -lg2o_types_slam3d
/usr/bin/ld: cannot find -lg2o_csparse_extension
/usr/bin/ld: cannot find -lg2o_opengl_helper
/usr/bin/ld: cannot find -lg2o_solver_dense
/usr/bin/ld: cannot find -lg2o_stuff
/usr/bin/ld: cannot find -lg2o_types_sclam2d
/usr/bin/ld: cannot find -lg2o_parser
/usr/bin/ld: cannot find -lg2o_solver_pcg
/usr/bin/ld: cannot find -lg2o_types_data
/usr/bin/ld: cannot find -lg2o_types_sim3
collect2: error: ld returned 1 exit status
CMakeFiles/testG2O.dir/build.make:94: recipe for target 'testG2O' failed
make[2]: *** [testG2O] Error 1
CMakeFiles/Makefile2:67: recipe for target 'CMakeFiles/testG2O.dir/all' failed
make[1]: *** [CMakeFiles/testG2O.dir/all] Error 2
Makefile:83: recipe for target 'all' failed
make: *** [all] Error 2
暴力解决方案，强行添加库搜索路径set(CMAKE_CXX_FLAGS "-L/home/yu/sources/g2o/install/lib")，修改CMakeLists.txt文件：
# testG2O的CMakeLists.txt
add_executable(testG2O main.cpp)
set(CMAKE_CXX_FLAGS "-L/home/yu/sources/g2o/install/lib") # add by cjj: force find path
SET(G2O_LIBS g2o_cli g2o_ext_freeglut_minimal g2o_simulator g2o_solver_slam2d_linear g2o_types_icp g2o_types_slam2d g2o_core g2o_interface g2o_solver_csparse g2o_solver_structure_only g2o_types_sba g2o_types_slam3d g2o_csparse_extension g2o_opengl_helper g2o_solver_dense g2o_stuff g2o_types_sclam2d g2o_parser g2o_solver_pcg g2o_types_data g2o_types_sim3 cxsparse )
target_link_libraries(testG2O ${G2O_LIBS})
编译成功：
Scanning dependencies of target testG2O
[ 50%] Building CXX object CMakeFiles/testG2O.dir/main.cpp.o
[100%] Linking CXX executable testG2O
[100%] Built target testG2O
执行./testG2O，还是找不到库：
./testG2O: error while loading shared libraries: libg2o_core.so: cannot open shared object file: No such file or directory
百度后的解决方案，添加临时库路径export LD_LIBRARY_PATH=/home/yu/tmp/g2oinstall/lib:$LD_LIBRARY_PATH，之后顺利执行。
测试 3
从CMakeLists.txt中看出只有 Eigen 库是必须的，没有 Eigen 库会导致构建失败。所以先来解决 Eigen 库的问题。
Eigen 库是纯头文件的库，只用将 Eigen 库源码下载下来，放到 g2o 项目的某个目录中，并在 CMakeLists.txt中添加 Eigen 库的目录即可。不需要FindEigen3.cmake模块去寻找本地 Eigen 库。
在下载好的 Eigen 项目中，新建 build 目录和 install 目录，在 build 目录中执行构建，添加自定义安装目录：cmake -DCMAKE_INSTALL_PREFIX=/home/yu/sources/eigen/install ..，构建编译及安装后，在 install 目录下生成两个文件夹include和share，将这两个文件夹拷贝到 g2o 目录的 EXTERNAL 目录下。
修改 CMakeLists.txt文件：
# yuh - for local eigen
#find_package(Eigen3 REQUIRED)
#if (TARGET Eigen3::Eigen)
# set(G2O_EIGEN3_EIGEN_TARGET Eigen3::Eigen)
# MESSAGE(STATUS "G2O_EIGEN3_EIGEN_TARGET is: ${G2O_EIGEN3_EIGEN_TARGET}")
#else()
# include_directories(${EIGEN3_INCLUDE_DIR})
# MESSAGE(STATUS "EIGEN3_INCLUDE_DIR is: ${EIGEN3_INCLUDE_DIR}")
#endif ()
# yuh - for inside eigen
include_directories(EXTERNAL/eigen3)
构建的结果中没有出现如[测试 1](#测试 1)和[测试 2](#测试 2)中的Found Eigen3输出信息，说明没有在/usr/include目录下搜索 Eigen 库，用的是 g2o 项目内的 Eigen 库。编译通过。
执行 bin 目录下的可执行文件./slam2d_g2o，能够运行。
PS：找到usr/include下的 eigen3 目录，里面只有 Eigen 目录， unsupported 目录和一个文件，按照这个最简单的库的内容重新简化 g2o 项目中添加的 Eigen 库的内容。
其他库的植入尚未完成。
测试 4
略
测试 5
在工程目录 g2o 下新建目录 build_px3se ，进入目录 build_px3se ，执行交叉编译cmake .. -DCMAKE_TOOLCHAIN_FILE=~/sources/eva/cmakemodules/px3se.cmake命令。
交叉编译工具px3se.cmake如下：
SET(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR arm)
SET(ROBOT_FULL_FEATURE ON)
SET(CMAKE_C_COMPILER /opt/tools/cross-toolchain/usr/bin/arm-rockchip-linux-gnueabihf-gcc)
SET(CMAKE_CXX_COMPILER /opt/tools/cross-toolchain/usr/bin/arm-rockchip-linux-gnueabihf-g++)
SET(CMAKE_SYSROOT /opt/tools/cross-toolchain/usr/arm-rockchip-linux-gnueabihf/sysroot)
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
初次交叉编译结果：
-- The C compiler identification is GNU 4.9.4
-- The CXX compiler identification is GNU 4.9.4
-- Check for working C compiler: /opt/tools/cross-toolchain/usr/bin/arm-rockchip-linux-gnueabihf-gcc
-- Check for working C compiler: /opt/tools/cross-toolchain/usr/bin/arm-rockchip-linux-gnueabihf-gcc -- works # c 工具链地址
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /opt/tools/cross-toolchain/usr/bin/arm-rockchip-linux-gnueabihf-g++
-- Check for working CXX compiler: /opt/tools/cross-toolchain/usr/bin/arm-rockchip-linux-gnueabihf-g++ -- works # c++ 工具链地址
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- CMAKE_RUNTIME_OUTPUT_DIRECTORY is /home/yu/sources/g2o/bin
-- CMAKE_LIBRARY_OUTPUT_DIRECTORY is /home/yu/sources/g2o/lib
-- CMAKE_INSTALL_PREFIX is /usr/local
-- Compiling on Unix
-- Could NOT find CHOLMOD (missing: CHOLMOD_INCLUDE_DIR CHOLMOD_LIBRARIES)
-- A library with BLAS API not found. Please specify library location.
-- A library with BLAS API not found. Please specify library location.
-- LAPACK requires BLAS.
-- Could NOT find CSPARSE (missing: CSPARSE_INCLUDE_DIR CSPARSE_LIBRARY)
-- Could NOT find OpenGL (missing: OPENGL_gl_LIBRARY OPENGL_INCLUDE_DIR)
-- Could NOT find QGLVIEWER (missing: QGLVIEWER_INCLUDE_DIR QGLVIEWER_LIBRARY)
-- Compiling g2o apps
-- Compiling g2o examples
-- Compiling with GCC
CMake Error at /usr/share/cmake-3.5/Modules/FindPackageHandleStandardArgs.cmake:148 (message):
Could NOT find Eigen3 (missing: EIGEN3_INCLUDE_DIR EIGEN3_VERSION_OK)
(Required is at least version "2.91.0") # Eigen库是必须的
Call Stack (most recent call first):
/usr/share/cmake-3.5/Modules/FindPackageHandleStandardArgs.cmake:388 (_FPHSA_FAILURE_MESSAGE)
cmake_modules/FindEigen3.cmake:82 (find_package_handle_standard_args)
CMakeLists.txt:362 (find_package)
-- Configuring incomplete, errors occurred!
See also "/home/yu/sources/g2o/build_px3se/CMakeFiles/CMakeOutput.log".
对比[测试 2](#测试 2)的输出，可以看出交叉编译的 c c++ 工具链发生了变化，指定了路径。而且依赖库都没有找到。但是其中只有 Eigen 库是必须的，没有 Eigen 库会导致构建失败。所以先来解决 Eigen 库的问题。参考[测试 3](#测试 3)。
构建成功，但是编译不通过：
Scanning dependencies of target csparse
[ 1%] Building C object EXTERNAL/csparse/CMakeFiles/csparse.dir/cs_add.c.o
arm-rockchip-linux-gnueabihf-gcc.br_real: error: unrecognized command line option ‘-msse2’
arm-rockchip-linux-gnueabihf-gcc.br_real: error: unrecognized command line option ‘-msse3’
arm-rockchip-linux-gnueabihf-gcc.br_real: error: unrecognized command line option ‘-mssse3’
arm-rockchip-linux-gnueabihf-gcc.br_real: error: unrecognized command line option ‘-msse4.1’
arm-rockchip-linux-gnueabihf-gcc.br_real: error: unrecognized command line option ‘-msse4.2’
EXTERNAL/csparse/CMakeFiles/csparse.dir/build.make:62: recipe for target 'EXTERNAL/csparse/CMakeFiles/csparse.dir/cs_add.c.o' failed
make[2]: *** [EXTERNAL/csparse/CMakeFiles/csparse.dir/cs_add.c.o] Error 1
CMakeFiles/Makefile2:103: recipe for target 'EXTERNAL/csparse/CMakeFiles/csparse.dir/all' failed
make[1]: *** [EXTERNAL/csparse/CMakeFiles/csparse.dir/all] Error 2
Makefile:149: recipe for target 'all' failed
make: *** [all] Error 2
估计是交叉编译器无法识别上述 sse 加速算法，直接屏蔽对应的CMakeLists.txt的内容，再次编译通过。
将 build_px3se 目录下生成的 lib 和 bin 目录打包压缩，放到开发板上，解压并添加当前 bin 的路径：
LD_LIBRARY_PATH=`pwd`/lib
即可执行 bin 目录下的可执行文件了。
其他依赖库如何添加，未完。
ceres 应用 cmake
测试 1
下载 ceres 源码库，安装依赖。在工程目录 ceres 下新建目录build，进入目录build，执行cmake ..命令：
-- The C compiler identification is GNU 5.4.0
-- The CXX compiler identification is GNU 5.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- CMAKE_RUNTIME_OUTPUT_DIRECTORY is: /home/yu/sources/ceres-solver/build/bin
-- CMAKE_LIBRARY_OUTPUT_DIRECTORY is: /home/yu/sources/ceres-solver/build/lib
-- Detected Ceres version: 2.0.0 from /home/yu/sources/ceres-solver/include/ceres/version.h
-- Detected available Ceres threading models: [CXX11_THREADS, OPENMP, NO_THREADS]
-- Building with C++11
-- No preference for use of exported Eigen CMake configuration set, and no hints for include directory provided. Defaulting to preferring an installed/exported Eigen CMake configuration if available.
-- Found installed version of Eigen: /usr/lib/cmake/eigen3
-- Found Eigen: /usr/include/eigen3 (found version "3.2.92")
-- Found Eigen version 3.2.92: /usr/include/eigen3
-- Enabling use of Eigen as a sparse linear algebra library.
-- Looking for sgemm_
-- Looking for sgemm_ - found
-- Looking for pthread.h
-- Looking for pthread.h - found
-- Looking for pthread_create
-- Looking for pthread_create - not found
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found
-- Found Threads: TRUE
-- A library with BLAS API found.
-- Found LAPACK library: /usr/lib/liblapack.so;/usr/lib/libblas.so
-- A library with BLAS API found.
-- Found AMD headers in: /usr/include/suitesparse
-- Found AMD library: /usr/lib/x86_64-linux-gnu/libamd.so
-- Found CAMD headers in: /usr/include/suitesparse
-- Found CAMD library: /usr/lib/x86_64-linux-gnu/libcamd.so
-- Found COLAMD headers in: /usr/include/suitesparse
-- Found COLAMD library: /usr/lib/x86_64-linux-gnu/libcolamd.so
-- Found CCOLAMD headers in: /usr/include/suitesparse
-- Found CCOLAMD library: /usr/lib/x86_64-linux-gnu/libccolamd.so
-- Found CHOLMOD headers in: /usr/include/suitesparse
-- Found CHOLMOD library: /usr/lib/x86_64-linux-gnu/libcholmod.so
-- Found SUITESPARSEQR headers in: /usr/include/suitesparse
-- Found SUITESPARSEQR library: /usr/lib/x86_64-linux-gnu/libspqr.so
-- Did not find Intel TBB library, assuming SuiteSparseQR was not compiled with TBB.
-- Found SUITESPARSE_CONFIG headers in: /usr/include/suitesparse
-- Found SUITESPARSE_CONFIG library: /usr/lib/x86_64-linux-gnu/libsuitesparseconfig.so
-- Found LIBRT library: /usr/lib/x86_64-linux-gnu/librt.so
-- Adding librt: /usr/lib/x86_64-linux-gnu/librt.so to SuiteSparse_config libraries (required on Linux & Unix [not OSX] if SuiteSparse is compiled with timing).
-- Did not find METIS library (optional SuiteSparse dependency)
-- Found SuiteSparse: TRUE (found version "4.4.6")
-- Found SuiteSparse 4.4.6, building with SuiteSparse.
-- Found CXSparse: /usr/include/suitesparse (found version "3.1.4")
-- Found CXSparse version: 3.1.4, building with CXSparse.
-- Building without Apple's Accelerate sparse support.
-- No preference for use of exported gflags CMake configuration set, and no hints for include/library directories provided. Defaulting to preferring an installed/exported gflags CMake configuration if available.
-- Failed to find installed gflags CMake configuration, searching for gflags build directories exported with CMake.
-- Found exported gflags build directory: /home/yu/tmp/lib/cmake/gflags
-- Detected gflags version: 2.2.2
-- Found Gflags: /home/yu/tmp/include
-- Found Google Flags header in: /home/yu/tmp/include, in namespace: google
-- No preference for use of exported glog CMake configuration set, and no hints for include/library directories provided. Defaulting to preferring an installed/exported glog CMake configuration if available.
-- Failed to find installed glog CMake configuration, searching for glog build directories exported with CMake.
-- Found exported glog build directory: /home/yu/sources/eva/cmake-build-debug/apps/third-party-libs/glog-0.3.5
-- Detected glog version: 0.3.5
-- Found Glog: glog::glog
-- Found Google Log (glog). Assuming glog was built with gflags support as gflags was found. This will make gflags a public dependency of Ceres.
-- Using Ceres threading model: CXX11_THREADS
-- Failed to find Google benchmark library, disabling build of benchmarks.
-- Building Ceres as a static library.
-- No build type specified; defaulting to CMAKE_BUILD_TYPE=Release.
-- Performing Test CHECK_CXX_FLAG_Wmissing_declarations
-- Performing Test CHECK_CXX_FLAG_Wmissing_declarations - Success
-- Performing Test CHECK_CXX_FLAG_Wno_unknown_pragmas
-- Performing Test CHECK_CXX_FLAG_Wno_unknown_pragmas - Success
-- Performing Test CHECK_CXX_FLAG_Wno_sign_compare
-- Performing Test CHECK_CXX_FLAG_Wno_sign_compare - Success
-- Performing Test CHECK_CXX_FLAG_Wno_unused_parameter
-- Performing Test CHECK_CXX_FLAG_Wno_unused_parameter - Success
-- Performing Test CHECK_CXX_FLAG_Wno_missing_field_initializers
-- Performing Test CHECK_CXX_FLAG_Wno_missing_field_initializers - Success
-- Creating configured Ceres config.h output directory: /home/yu/sources/ceres-solver/build/config/ceres/internal
-- Enabling CERES_USE_EIGEN_SPARSE in Ceres config.h
-- Enabling CERES_NO_ACCELERATE_SPARSE in Ceres config.h
-- Enabling CERES_USE_CXX11_THREADS in Ceres config.h
-- Performing Test CHECK_CXX_FLAG_Wno_missing_declarations
-- Performing Test CHECK_CXX_FLAG_Wno_missing_declarations - Success
-- Build the examples.
-- Configuring done
CMake Error in internal/ceres/CMakeLists.txt:
Imported target "glog::glog" includes non-existent path
"/home/yu/sources/eva/apps/third-party-libs/glog-0.3.5/src"
in its INTERFACE_INCLUDE_DIRECTORIES. Possible reasons include:
* The path was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and references files it does not
provide.
CMake Error in internal/ceres/CMakeLists.txt:
Imported target "glog::glog" includes non-existent path
"/home/yu/sources/eva/apps/third-party-libs/glog-0.3.5/src"
in its INTERFACE_INCLUDE_DIRECTORIES. Possible reasons include:
* The path was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and references files it does not
provide.
CMake Error in internal/ceres/CMakeLists.txt:
Imported target "glog::glog" includes non-existent path
"/home/yu/sources/eva/apps/third-party-libs/glog-0.3.5/src"
in its INTERFACE_INCLUDE_DIRECTORIES. Possible reasons include:
* The path was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and references files it does not
provide.
CMake Error in internal/ceres/CMakeLists.txt:
Imported target "glog::glog" includes non-existent path
"/home/yu/sources/eva/apps/third-party-libs/glog-0.3.5/src"
in its INTERFACE_INCLUDE_DIRECTORIES. Possible reasons include:
* The path was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and references files it does not
provide.
-- Generating done
-- Build files have been written to: /home/yu/sources/ceres-solver/build
首先，发现在/usr/lib/x86_64-linux-gnu/目录下是安装了 gflags 和 glog 库的，在/usr/include/目录下也能找到 gflags 和 glog 的头文件。但是上述 cmake 过程不是在该目录下找到 glog 库的。查看 ceres 的 cmake 目录下的FindGflags.cmake文件和FindGlog.cmake文件，其中说明了如果未指定GFLAGS_PREFER_EXPORTED_GFLAGS_CMAKE_CONFIGURATION和GLOG_PREFER_EXPORTED_GLOG_CMAKE_CONFIGURATION，cmake 将优先查找已经 install / exported 的库，其次再进行遍历，在/usr/include目录下查找对应的头文件。当前未指定搜索路径。
从上述 cmake 结果的 gflags 库部分看，找到了 exported 的某个 gflags 库：
-- No preference for use of exported gflags CMake configuration set, and no hints for include/library directories provided. Defaulting to preferring an installed/exported gflags CMake configuration if available. # 没有指定搜索方式
-- Failed to find installed gflags CMake configuration, searching for gflags build directories exported with CMake. # 没有找到 installed 的 gflags，尝试找 exported 的 gflags
-- Found exported gflags build directory: /home/yu/tmp/lib/cmake/gflags # 找到了 exported 的 gflags，在某个目录下
-- Detected gflags version: 2.2.2 # 输出 gflags 的安装版本
-- Found Gflags: /home/yu/tmp/include # gflags 的头文件路径
-- Found Google Flags header in: /home/yu/tmp/include, in namespace: google
从上述 cmake 结果的 glog 库部分看，找到了 exported 的某个 glog 库：
-- No preference for use of exported glog CMake configuration set, and no hints for include/library directories provided. Defaulting to preferring an installed/exported glog CMake configuration if available. # 没有指定搜索方式
-- Failed to find installed glog CMake configuration, searching for glog build directories exported with CMake. # 没有找到 installed 的 glog，尝试找 exported 的 glog
-- Found exported glog build directory: /home/yu/sources/eva/cmake-build-debug/apps/third-party-libs/glog-0.3.5 # 找到了 exported 的 glog，在某个目录下
-- Detected glog version: 0.3.5 # 输出 glog 的安装版本
-- Found Glog: glog::glog
-- Found Google Log (glog). Assuming glog was built with gflags support as gflags was found. This will make gflags a public dependency of Ceres.
之后的 error 也是因为找到的是在别的项目中安装的 glog 库，文件并不完整，导致找不到库，进而在编译过程中产生其他未知错误：
CMake Error in internal/ceres/CMakeLists.txt:
Imported target "glog::glog" includes non-existent path
"/home/yu/sources/eva/apps/third-party-libs/glog-0.3.5/src"
in its INTERFACE_INCLUDE_DIRECTORIES. Possible reasons include:
* The path was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and references files it does not
provide.
CMake Error in internal/ceres/CMakeLists.txt:
Imported target "glog::glog" includes non-existent path
"/home/yu/sources/eva/apps/third-party-libs/glog-0.3.5/src"
in its INTERFACE_INCLUDE_DIRECTORIES. Possible reasons include:
* The path was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and references files it does not
provide.
CMake Error in internal/ceres/CMakeLists.txt:
Imported target "glog::glog" includes non-existent path
"/home/yu/sources/eva/apps/third-party-libs/glog-0.3.5/src"
in its INTERFACE_INCLUDE_DIRECTORIES. Possible reasons include:
* The path was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and references files it does not
provide.
CMake Error in internal/ceres/CMakeLists.txt:
Imported target "glog::glog" includes non-existent path
"/home/yu/sources/eva/apps/third-party-libs/glog-0.3.5/src"
in its INTERFACE_INCLUDE_DIRECTORIES. Possible reasons include:
* The path was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and references files it does not
provide.
由于电脑中存在多个项目，安装了不同的 gflags 库和 glog 库，为了统一搜索路径，避免上述问题，需要指定搜索方式，重新构建：
cmake \
-DGFLAGS_PREFER_EXPORTED_GFLAGS_CMAKE_CONFIGURATION=FALSE \ # 指定优先搜索/usr/include路径
-DGLOG_PREFER_EXPORTED_GLOG_CMAKE_CONFIGURATION=FALSE ..# 指定优先搜索/usr/include路径
构建结果：
-- The C compiler identification is GNU 5.4.0
-- The CXX compiler identification is GNU 5.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- CMAKE_RUNTIME_OUTPUT_DIRECTORY is: /home/yu/sources/ceres-solver/build/bin
-- CMAKE_LIBRARY_OUTPUT_DIRECTORY is: /home/yu/sources/ceres-solver/build/lib
-- Detected Ceres version: 2.0.0 from /home/yu/sources/ceres-solver/include/ceres/version.h
-- Detected available Ceres threading models: [CXX11_THREADS, OPENMP, NO_THREADS]
-- Building with C++11
-- No preference for use of exported Eigen CMake configuration set, and no hints for include directory provided. Defaulting to preferring an installed/exported Eigen CMake configuration if available.
-- Found installed version of Eigen: /usr/lib/cmake/eigen3
-- Found Eigen: /usr/include/eigen3 (found version "3.2.92")
-- Found Eigen version 3.2.92: /usr/include/eigen3
-- Enabling use of Eigen as a sparse linear algebra library.
-- Looking for dgemm_
-- Looking for dgemm_ - found
-- Looking for pthread.h
-- Looking for pthread.h - found
-- Looking for pthread_create
-- Looking for pthread_create - not found
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found
-- Found Threads: TRUE
-- A library with BLAS API found.
-- Found LAPACK library: /usr/lib/liblapack.so;/usr/lib/libf77blas.so;/usr/lib/libatlas.so
-- A library with BLAS API found.
-- Found AMD headers in: /usr/include/suitesparse
-- Found AMD library: /usr/lib/x86_64-linux-gnu/libamd.so
-- Found CAMD headers in: /usr/include/suitesparse
-- Found CAMD library: /usr/lib/x86_64-linux-gnu/libcamd.so
-- Found COLAMD headers in: /usr/include/suitesparse
-- Found COLAMD library: /usr/lib/x86_64-linux-gnu/libcolamd.so
-- Found CCOLAMD headers in: /usr/include/suitesparse
-- Found CCOLAMD library: /usr/lib/x86_64-linux-gnu/libccolamd.so
-- Found CHOLMOD headers in: /usr/include/suitesparse
-- Found CHOLMOD library: /usr/lib/x86_64-linux-gnu/libcholmod.so
-- Found SUITESPARSEQR headers in: /usr/include/suitesparse
-- Found SUITESPARSEQR library: /usr/lib/x86_64-linux-gnu/libspqr.so
-- Did not find Intel TBB library, assuming SuiteSparseQR was not compiled with TBB.
-- Found SUITESPARSE_CONFIG headers in: /usr/include/suitesparse
-- Found SUITESPARSE_CONFIG library: /usr/lib/x86_64-linux-gnu/libsuitesparseconfig.so
-- Found LIBRT library: /usr/lib/x86_64-linux-gnu/librt.so
-- Adding librt: /usr/lib/x86_64-linux-gnu/librt.so to SuiteSparse_config libraries (required on Linux & Unix [not OSX] if SuiteSparse is compiled with timing).
-- Did not find METIS library (optional SuiteSparse dependency)
-- Found SuiteSparse: TRUE (found version "4.4.6")
-- Found SuiteSparse 4.4.6, building with SuiteSparse.
-- Found CXSparse: /usr/include/suitesparse (found version "3.1.4")
-- Found CXSparse version: 3.1.4, building with CXSparse.
-- Building without Apple's Accelerate sparse support.
-- GFLAGS_INCLUDE_DIR is: /usr/include # 指定优先搜索路径后
-- GFLAGS_LIBRARY is: /usr/lib/x86_64-linux-gnu/libgflags.so # 指定优先搜索路径后
-- Performing Test GFLAGS_IN_GOOGLE_NAMESPACE
-- Performing Test GFLAGS_IN_GOOGLE_NAMESPACE - Success
-- Found Gflags: /usr/include # 指定优先搜索路径后
-- Found Google Flags header in: /usr/include, in namespace: google # 指定优先搜索路径后
-- GLOG_INCLUDE_DIR is: /usr/include # 指定优先搜索路径后
-- GLOG_LIBRARY is: /usr/lib/x86_64-linux-gnu/libglog.so # 指定优先搜索路径后
-- Found Glog: /usr/include # 指定优先搜索路径后
-- Found Google Log (glog). Assuming glog was built with gflags support as gflags was found. This will make gflags a public dependency of Ceres.
-- Using Ceres threading model: CXX11_THREADS
-- Failed to find Google benchmark library, disabling build of benchmarks.
-- Building Ceres as a static library. # 后续值得关注
-- No build type specified; defaulting to CMAKE_BUILD_TYPE=Release.
-- Performing Test CHECK_CXX_FLAG_Wmissing_declarations
-- Performing Test CHECK_CXX_FLAG_Wmissing_declarations - Success
-- Performing Test CHECK_CXX_FLAG_Wno_unknown_pragmas
-- Performing Test CHECK_CXX_FLAG_Wno_unknown_pragmas - Success
-- Performing Test CHECK_CXX_FLAG_Wno_sign_compare
-- Performing Test CHECK_CXX_FLAG_Wno_sign_compare - Success
-- Performing Test CHECK_CXX_FLAG_Wno_unused_parameter
-- Performing Test CHECK_CXX_FLAG_Wno_unused_parameter - Success
-- Performing Test CHECK_CXX_FLAG_Wno_missing_field_initializers
-- Performing Test CHECK_CXX_FLAG_Wno_missing_field_initializers - Success
-- Creating configured Ceres config.h output directory: /home/yu/sources/ceres-solver/build/config/ceres/internal
-- Enabling CERES_USE_EIGEN_SPARSE in Ceres config.h
-- Enabling CERES_NO_ACCELERATE_SPARSE in Ceres config.h
-- Enabling CERES_USE_CXX11_THREADS in Ceres config.h
-- Performing Test CHECK_CXX_FLAG_Wno_missing_declarations
-- Performing Test CHECK_CXX_FLAG_Wno_missing_declarations - Success
-- Build the examples.
-- Configuring done
-- Generating done
-- Build files have been written to: /home/yu/sources/ceres-solver/build
干净的构建结果。继续编译，成功。
在 build 目录下执行./bin/pose_graph_2d文件。第一次尝试下面的输入：
# build目录下
./bin/pose_graph_2d ~/sources/openslam_vertigo/datasets/city10000/originalDataset/city10000.g2o
结果出错：
input:
F1031 09:28:06.848613 14240 pose_graph_2d.cc:163] Check failed: FLAGS_input != "" Need to specify the filename to read. # 文件名是空的
*** Check failure stack trace: ***
@ 0x7f51972275cd google::LogMessage::Fail()
@ 0x7f5197229433 google::LogMessage::SendToLog()
@ 0x7f519722715b google::LogMessage::Flush()
@ 0x7f5197229e1e google::LogMessageFatal::~LogMessageFatal()
@ 0x406e64 main
@ 0x7f51956cf830 __libc_start_main
@ 0x4072f9 _start
@ (nil) (unknown)
Aborted
输入的参数并没有传入进代码。直接在代码中修改文件路径：
// pose_graph_2d.cc
DEFINE_string(input, "~/sources/openslam_vertigo/datasets/city10000/originalDataset/city10000.g2o", "The pose graph definition filename in g2o format."); # 将路径添加到代码中
文件路径能输出，但是读取文件又失败了。根据ReadG2oFile()函数的说明，文件的内容是正确的。但是没有读出来。
input: ~/sources/openslam_vertigo/datasets/city10000/originalDataset/city10000.g2o
F1031 09:32:49.220307 15534 pose_graph_2d.cc:176] Check failed: ceres::examples::ReadG2oFile(FLAGS_input, &poses, &constraints) Error reading the file: ~/sources/openslam_vertigo/datasets/city10000/originalDataset/city10000.g2o # 读取文件内容失败
*** Check failure stack trace: ***
@ 0x7f3f362b95cd google::LogMessage::Fail()
@ 0x7f3f362bb433 google::LogMessage::SendToLog()
@ 0x7f3f362b915b google::LogMessage::Flush()
@ 0x7f3f362bbe1e google::LogMessageFatal::~LogMessageFatal()
@ 0x406eca main
@ 0x7f3f34761830 __libc_start_main
@ 0x4072f9 _start
@ (nil) (unknown)
Aborted
可能是文件有问题，更换其他普通文件尝试读取，比如某个 .txt文件，结果读取成功。对比差异发现问题：文件路径输入为~/前缀时，无法正常读取文件内容，当文件路径输入为/home/yu/前缀时，可以正确读取文件内容。
继续修改输入文件的路径，用/home/yu/前缀添加到代码中：
// pose_graph_2d.cc
DEFINE_string(input, "/home/yu/sources/openslam_vertigo/datasets/city10000/originalDataset/city10000.g2o", "The pose graph definition filename in g2o format.");
得到正常的算法输出：
input: /home/yu/sources/openslam_vertigo/datasets/city10000/originalDataset/city10000.g2o
Number of poses: 10000
Number of constraints: 20687
Solver Summary (v 2.0.0-eigen-(3.2.92)-lapack-suitesparse-(4.4.6)-cxsparse-(3.1.4)-eigensparse-no_openmp)
Original Reduced
Parameter blocks 30000 29997
Parameters 30000 29997
Residual blocks 20687 20687
Residuals 62061 62061
Minimizer TRUST_REGION
Sparse linear algebra library SUITE_SPARSE
Trust region strategy LEVENBERG_MARQUARDT
Given Used
Linear solver SPARSE_NORMAL_CHOLESKY SPARSE_NORMAL_CHOLESKY
Threads 1 1
Linear solver ordering AUTOMATIC 29997
Cost:
Initial 3.270813e+08
Final 2.559927e+02
Change 3.270811e+08
Minimizer iterations 10
Successful steps 10
Unsuccessful steps 0
Time (in seconds):
Preprocessor 0.026131
Residual only evaluation 0.030149 (10)
Jacobian & residual evaluation 0.086377 (10)
Linear solver 0.373010 (10)
Minimizer 0.539330
Postprocessor 0.001327
Total 0.566788
Termination: CONVERGENCE (Function tolerance reached. |cost_change|/cost: 5.698316e-07 <= 1.000000e-06)
再次试验教程上的说明，在可执行文件后添加数据集的路径：
/path/to/bin/pose_graph_2d /path/to/dataset/dataset.g2o
重置原始代码（即不在源代码中添加数据集的路径），执行以下命令：
./bin/pose_graph_2d /home/yu/sources/openslam_vertigo/datasets/city10000/originalDataset/city10000.g2o
得到错误的输出提示，说明文件路径没有输入到算法中：
input:
F1031 09:43:32.214087 19312 pose_graph_2d.cc:163] Check failed: FLAGS_input != "" Need to specify the filename to read.
*** Check failure stack trace: ***
@ 0x7fc525c1a5cd google::LogMessage::Fail()
@ 0x7fc525c1c433 google::LogMessage::SendToLog()
@ 0x7fc525c1a15b google::LogMessage::Flush()
@ 0x7fc525c1ce1e google::LogMessageFatal::~LogMessageFatal()
@ 0x406e64 main
@ 0x7fc5240c2830 __libc_start_main
@ 0x4072f9 _start
@ (nil) (unknown)
Aborted
需要研究一下 gflags 和输入参数之间的关系。百度中例程说在输入参数时需要添加对应的 flag 名，如下在数据集路径前添加-input=前缀：
./bin/pose_graph_2d -input=/home/yu/sources/openslam_vertigo/datasets/city10000/originalDataset/city10000.g2o
能正常读取数据集文件并且输出算法结果。
参考 gflags 官方文档Setting Flags on the Command Line小结：
测试 2
清除工程目录 ceres 下目录build的内容，进入目录build，执行cmake -DGFLAGS_PREFER_EXPORTED_GFLAGS_CMAKE_CONFIGURATION=FALSE -DGLOG_PREFER_EXPORTED_GLOG_CMAKE_CONFIGURATION=FALSE -DCMAKE_INSTALL_PREFIX=/home/yu/sources/ceres-solver/install ..命令，将 ceres 安装到指定目录/home/yu/sources/ceres-solver/install下。
执行make和make install安装成功。
另外建立新的工程 testCERES ，新建 CMakeLists.txt，按照 g2o 的调用方式修改文件如下：
# testCERES的CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
project(testCERES)
set(CMAKE_CXX_STANDARD 11)
SET(CMAKE_MODULE_PATH /home/yu/sources/ceres-solver/install/lib/cmake/Ceres)
MESSAGE(STATUS "MODULE_PATH: " ${CMAKE_MODULE_PATH})
find_package(Ceres REQUIRED)
MESSAGE(STATUS "CERES_LIBRARIES is ${CERES_LIBRARIES}")
IF(Ceres_FOUND)
message(STATUS "Ceres lib is found:" ${CERES_INCLUDE_DIRS})
ENDIF(Ceres_FOUND)
构建出错：
-- The C compiler identification is GNU 5.4.0
-- The CXX compiler identification is GNU 5.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- MODULE_PATH: /home/yu/sources/ceres-solver/install/lib/cmake/Ceres
CMake Error at CMakeLists.txt:11 (find_package):
By not providing "FindCeres.cmake" in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by "Ceres", but
CMake did not find one. # 找不到FindCeres.cmake
Could not find a package configuration file provided by "Ceres" with any of
the following names:
CeresConfig.cmake # 找不到CeresConfig.cmake
ceres-config.cmake
Add the installation prefix of "Ceres" to CMAKE_PREFIX_PATH or set
"Ceres_DIR" to a directory containing one of the above files. If "Ceres"
provides a separate development package or SDK, be sure it has been
installed.
-- Configuring incomplete, errors occurred!
See also "/home/yu/CLionProjects/testCERES/build/CMakeFiles/CMakeOutput.log".
指明找不到FindCeres.cmake或者CeresConfig.cmake文件。但是路径/home/yu/sources/ceres-solver/install/lib/cmake/Ceres确实包含了CeresConfig.cmake文件。
参考ceres-solver.org官网使用 ceres 的教程，指明了如果安装或者导出了 ceres ，需要将安装后的 CeresConfig.cmake文件所在的路径指定给Ceres_DIR变量。
Irrespective of whether Ceres was installed or exported, if multiple versions are detected, set:
Ceres_DIRto control which is used. If Ceres was installedCeres_DIRshould be the path to the directory containing the installedCersConfig.cmakefile (e.g./usr/local/share/Ceres). If Ceres was exported, thenCeres_DIRshould be the path to the exported Ceres build directory.
修改上述CMakeLists.txt文件，将CeresConfig.cmake文件的路径指定给Ceres_DIR变量，而不是CMAKE_MODULE_PATH变量：
# testCERES的CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
project(testCERES)
set(CMAKE_CXX_STANDARD 11)
SET(Ceres_DIR /home/yu/sources/ceres-solver/install/lib/cmake/Ceres)
MESSAGE(STATUS "Ceres_DIR: " ${Ceres_DIR})
find_package(Ceres REQUIRED)
MESSAGE(STATUS "CERES_LIBRARIES is ${CERES_LIBRARIES}")
IF(Ceres_FOUND)
message(STATUS "Ceres lib is found:" ${CERES_INCLUDE_DIRS})
ENDIF(Ceres_FOUND)
构建成功。
-- The C compiler identification is GNU 5.4.0
-- The CXX compiler identification is GNU 5.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Ceres_DIR: /home/yu/sources/ceres-solver/install/lib/cmake/Ceres
-- Looking for pthread.h
-- Looking for pthread.h - found
-- Looking for pthread_create
-- Looking for pthread_create - not found
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found
-- Found Threads: TRUE
-- Found installed version of Eigen: /usr/lib/cmake/eigen3
-- Found required Ceres dependency: Eigen version 3.2.92 in /usr/include/eigen3
-- GLOG_INCLUDE_DIR is: /usr/include
-- GLOG_LIBRARY is: /usr/lib/x86_64-linux-gnu/libglog.so
-- Found required Ceres dependency: glog
-- GFLAGS_INCLUDE_DIR is: /usr/include
-- GFLAGS_LIBRARY is: /usr/lib/x86_64-linux-gnu/libgflags.so
-- Performing Test GFLAGS_IN_GOOGLE_NAMESPACE
-- Performing Test GFLAGS_IN_GOOGLE_NAMESPACE - Success
-- Found required Ceres dependency: gflags
-- Found Ceres version: 2.0.0 installed in: /home/yu/sources/ceres-solver/install with components: [EigenSparse, SparseLinearAlgebraLibrary, LAPACK, SuiteSparse, CXSparse, SchurSpecializations]
-- CERES_LIBRARIES is ceres
-- Ceres lib is found:
-- Configuring done
-- Generating done
-- Build files have been written to: /home/yu/CLionProjects/testCERES/build
参考 ceres-solver.org官网安装及使用教程的Local installations部分，指明了一种自定义 ceres 库的寻找方法：
# cmake 过程
-DCMAKE_INSTALL_PREFIX="/some/where/local" # 自定义 ceres 安装路径
# 工程 CMakeLists.txt 文件
find_package(Ceres REQUIRED PATHS "/some/where/local/") # 添加安装路径
# testCERES的CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
project(testCERES)
set(CMAKE_CXX_STANDARD 11)
find_package(Ceres REQUIRED PATHS /home/yu/sources/ceres-solver/install)
IF(Ceres_FOUND)
include_directories(${CERES_INCLUDE_DIRS})
MESSAGE(STATUS "CERES_INCLUDE_DIRS is ${CERES_INCLUDE_DIRS}")
MESSAGE(STATUS "CERES_LIBRARIES is ${CERES_LIBRARIES}")
ENDIF(Ceres_FOUND)
能够得到上述一样的构建结果。
但是，两者目前都有一个问题，能找到安装位置的 ceres 库，但是没有CERES_INCLUDE_DIRS路径的输出。ceres 的 CeresConfig.cmake文件中说：
NOTE: There is no equivalent of CERES_INCLUDE_DIRS as the exported CMake target already includes the definition of its public include directories.
暂时忽略这个问题。
继续添加只依赖 ceres 的测试程序。修改CMakeLists.txt文件：
# testCERES的CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
project(testCERES)
set(CMAKE_CXX_STANDARD 11)
# method 1
#SET(Ceres_DIR /home/yu/sources/ceres-solver/install/lib/cmake/Ceres)
#MESSAGE(STATUS "Ceres_DIR: " ${Ceres_DIR})
# method 2
find_package(Ceres REQUIRED PATHS /home/yu/sources/ceres-solver/install)
IF(Ceres_FOUND)
include_directories(${CERES_INCLUDE_DIRS})
MESSAGE(STATUS "CERES_INCLUDE_DIRS is ${CERES_INCLUDE_DIRS}")
MESSAGE(STATUS "CERES_LIBRARIES is ${CERES_LIBRARIES}")
ENDIF(Ceres_FOUND)
add_executable(testCERES main.cpp)
target_link_libraries(testCERES ${CERES_LIBRARIES})
编译运行成功。
PS： ceres 的 CeresConfig.cmake文件中已经包含了对 gflags 和 glog 和 Eigen3 库的搜索和添加，所以在测试代码的 CMakeLists.txt文件中不再需要单独搜索上述库。
继续修改需要同时调用 ceres ，gflags ，和 glog 的库的测试程序，上述CMakeLists.txt编译通过，但是运行时出现问题：
Scanning dependencies of target testCERES
[ 50%] Building CXX object CMakeFiles/testCERES.dir/main.cpp.o
/home/yu/CLionProjects/testCERES/main.cpp: In function ‘int main(int, char**)’:
/home/yu/CLionProjects/testCERES/main.cpp:160:5: error: ‘CERES_GFLAGS_NAMESPACE’ has not been declared
CERES_GFLAGS_NAMESPACE::ParseCommandLineFlags(&argc, &argv, true);
^
CMakeFiles/testCERES.dir/build.make:62: recipe for target 'CMakeFiles/testCERES.dir/main.cpp.o' failed
make[2]: *** [CMakeFiles/testCERES.dir/main.cpp.o] Error 1
CMakeFiles/Makefile2:67: recipe for target 'CMakeFiles/testCERES.dir/all' failed
make[1]: *** [CMakeFiles/testCERES.dir/all] Error 2
Makefile:83: recipe for target 'all' failed
make: *** [all] Error 2
说明CERES_GFLAGS_NAMESPACE未定义。该测试代码来自原 ceres 的例程 pose_graph_2d.cc，在原 ceres 中全局搜索变量CERES_GFLAGS_NAMESPACE，发现以下定义：
# ceres的CMakeLists.txt
# GFlags.
if (GFLAGS)
# Don't search with REQUIRED as we can continue without gflags.
find_package(Gflags)
if (GFLAGS_FOUND)
message("-- Found Google Flags header in: ${GFLAGS_INCLUDE_DIRS}, "
"in namespace: ${GFLAGS_NAMESPACE}")
add_definitions(-DCERES_GFLAGS_NAMESPACE=${GFLAGS_NAMESPACE})
else (GFLAGS_FOUND)
message("-- Did not find Google Flags (gflags), Building without gflags "
"- no tests or tools will be built!")
update_cache_variable(GFLAGS OFF)
endif (GFLAGS_FOUND)
else (GFLAGS)
message("-- Google Flags disabled; no tests or tools will be built!")
# Mark as advanced (remove from default GUI view) the gflags search
# variables in case user enabled GFLAGS, FindGflags did not find it, so
# made search variables visible in GUI for user to set, but then user disables
# GFLAGS instead of setting them.
mark_as_advanced(FORCE GFLAGS_INCLUDE_DIR
GFLAGS_LIBRARY
GFLAGS_NAMESPACE)
endif (GFLAGS)
其中对DCERES_GFLAGS_NAMESPACE有独立的定义。不包含在 ceres 的 CeresConfig.cmake文件中。因此需要在测试代码的CMakeLists.txt文件中添加对该变量的定义，修改如下：
# testCERES的CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
project(testCERES)
set(CMAKE_CXX_STANDARD 11)
# method 1
#SET(Ceres_DIR /home/yu/sources/ceres-solver/install/lib/cmake/Ceres)
#MESSAGE(STATUS "Ceres_DIR: " ${Ceres_DIR})
# method 2
find_package(Ceres REQUIRED PATHS /home/yu/sources/ceres-solver/install)
IF(Ceres_FOUND)
include_directories(${CERES_INCLUDE_DIRS})
MESSAGE(STATUS "CERES_INCLUDE_DIRS is ${CERES_INCLUDE_DIRS}")
MESSAGE(STATUS "CERES_LIBRARIES is ${CERES_LIBRARIES}")
ENDIF(Ceres_FOUND)
MESSAGE(STATUS "GFLAGS_NAMESPACE is: ${GFLAGS_NAMESPACE}")
if (GFLAGS_FOUND)
MESSAGE(STATUS "Found Google Flags header in: ${GFLAGS_INCLUDE_DIRS}, "
"in namespace: ${GFLAGS_NAMESPACE}")
add_definitions(-DCERES_GFLAGS_NAMESPACE=${GFLAGS_NAMESPACE})
ENDIF(GFLAGS_FOUND)
MESSAGE(STATUS "CERES_GFLAGS_NAMESPACE is: ${CERES_GFLAGS_NAMESPACE}")
add_executable(testCERES main.cpp)
target_link_libraries(testCERES ${CERES_LIBRARIES})
编译运行通过。
测试 3
测试 4
测试 5
图优化数据集
位于上述工程的datasets目录下，包含 2d 和 3d 图优化 g2o 数据集。