未安装Ceres

编译VINs的时候，遇到了这个问题，是没安装Ceres导致的
`CMake Error at VINS-Mono/camera_model/CMakeLists.txt:19 (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.

Could not find a package configuration file provided by “Ceres” with any of
the following names:

CeresConfig.cmake
ceres-config.cmake

`
解决方案如下：

sudo gedit /etc/apt/sources.list

将下面这句话复制在打开文件的第一行

deb http://cz.archive.ubuntu.com/ubuntu trusty main universe

sudo apt-get update

sudo apt-get install liblapack-dev libsuitesparse-dev libcxsparse3.1.2 libgflags-dev

sudo apt-get install libgoogle-glog-dev libgtest-dev

git clone https://github.com.cnpmjs.org/ceres-solver/ceres-solver 

cd ceres-solver

 sudo mkdir build 

cd  build

sudo cmake ..

sudo make -j8

sudo make install

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