Results 2 issues of huangkai

My Development Environment is: OS: Arch Linux x86_64 cmake: 3.9.3 gcc: 7.2.0 eigen: 3.3.4 suitesparse 4.5.4 opencv: 3.3.0 After I compiled g2o, I tried it with a simple curve fitting...

For lyra::group, I'd like to use the "|" operator chain way, but no example in the docs, and it seems that the callback passed into lyra::group isn't called. ```c++ #include...