系统状态
- OS: Ubuntu 16.04 X86-64(arch)
- 安装了ros kinetic，所以opencv3.0已经存在在ros安装目录的include和lib目录中
- 安装了Python2.7和Python3.5，注意区分pip3和pip，python3和python，opensfm中使用python2
- 安装了eigen，使用apt-get
编译安装opengv
- Modify the CMakeLists.txt in the root dir: turn on BUILD_PYTHON
- cmake and make, then install.
编译安装ceres solver
- Add the build option: -fPIC to cmake_cxx_flags and cmake_c_flags to all the signal
Compile opensfm
relocation R_AARCH64_ADR_PREL_PG_HI21 against external symbol `__stack_chk_guard@@GLIBC_2.17' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: /usr/local/lib/libceres.a(loss_function.cc.o)(.text+0x11c): unresolvable R_AARCH64_ADR_PREL_PG_HI21 relocation against symbol `__stack_chk_guard@@GLIBC_2.17'
/usr/bin/ld: final link failed: Bad value
collect2: error: ld returned 1 exit status
Eigen::map<>()
int array[9];
for(int i = 0; i < 9; ++i) array[i] = i;
cout << Map<Matrix3i>(array) << endl;
Output:
0 3 6
1 4 7
2 5 8
注意以上map得到的结果是先填充行再填充列的
Eigen block <> ()
/#include <Eigen/Dense>
/#include <iostream>
using namespace std;
int main()
{
Eigen::MatrixXf m(4,4);
m << 1, 2, 3, 4,
5, 6, 7, 8,
9,10,11,12,
13,14,15,16;
cout << "Block in the middle" << endl;
cout << m.block<2,2>(1,1) << endl << endl;
for (int i = 1; i <= 3; ++i)
{
cout << "Block of size " << i << "x" << i << endl;
cout << m.block(0,0,i,i) << endl << endl;
}
}
output:
Block in the middle
6 7
10 11
Block of size 1x1
1
Block of size 2x2
1 2
5 6
Block of size 3x3
1 2 3
5 6 7
9 10 11