undefined reference to `nanoflann::KdTreeFLANN<pcl::PointXYZI>::KdTreeFLANN(nanoflann::KdTreeFLANN<pcl::PointXYZI> const&)

[ubicray]

Hey!
First of all, great work!
I've been looking for a replacement for FAST_LIO_SAM, wanted to give this one a try
I keep getting this error when trying to build tho:

ros1_ws/install/nano_gicp/lib/libnanoflann.so: undefined reference to `nanoflann::KdTreeFLANNpcl::PointXYZI::KdTreeFLANN(nanoflann::KdTreeFLANNpcl::PointXYZI const&)'
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [CMakeFiles/fast_lio_sam_sc_qn_node.dir/build.make:324: devel/lib/fast_lio_sam_sc_qn/fast_lio_sam_sc_qn_node] Error 1
make[1]: *** [CMakeFiles/Makefile2:2759: CMakeFiles/fast_lio_sam_sc_qn_node.dir/all] Error 2
make: *** [Makefile:146: all] Error 2

I believe it's because there are 2 distinct libs named nanoflann included
I would like to not have to build packages in separate steps
How would I go about achieving that? Or would you recommend going for the SC-less version?

[engcang]

@ubicray
Hi. You are right.
I did not recognize there are two files with same names.
I think it should be solved with the new commit.
Please pull the latest code and tell me if it works

[ubicray]

@engcang thanks for the fast response! Now the compiler complains about a lot of redefinitions between the nanoflann headers.
The nanoflann_impl.hpp and nanoflann header of scancontext are very similar with only a few lines of difference between them. Maybe 1 of them can be taken out and the other one used? What do you think?

[engcang]

@ubicray
Yeah you are right. So I just rolled back it to the former version.
Please try with catkin build instead of catkin_make
I am using Ubuntu 20.04 and ROS noetic.
I cannot reproduce the error you reported at first. Can you specify your environments?

[ubicray]

@engcang
I need to use colcon as I have ROS2 in the pipeline too and would like to be able to use the same tooling.
I can manage the changes due to using install space and make a PR here if you'd like me to, it'd be necessary for your work to behave well in production-like systems.
Would still need your help regarding all the redefinitions. Do these files need to be so different? I do remember using Scancontext and nanogicp together on some other project that didn't have such clashes

[engcang]

@ubicray
As you can check, I put the Scancontext and Nanogicp as submodules without changing the original author's files.
If possible, I want to keep them unchanged, as they are not my works and hence imported as submodules.
Can you show me the other project that uses Scancontext and Nanogicp together?

[ubicray]

@engcang my apologies, thought faster_lio_sam had it.
Okay, understand why you'd want them untouched.
To your knowledge, if I were to take nanoflann header out of scancontext and use the one that comes with nanogicp, should it work? I'll try that to get this setup working

[engcang]

@ubicray
Thank you for your understanding! This repository is mainly for promoting the Quatro, but not for product sales! Thus I want to keep submodules as untouched.
For your new question, I guess, yes, it should work with or without little modification of code.
Please let me know after you try it with the forked version of this repository!

[ubicray]

Interestingly enough, I keep seeing the error I mentioned regarding `nanoflann::KdTreeFLANNpcl::PointXYZI::KdTreeFLANN(nanoflann::KdTreeFLANNpcl::PointXYZI const&)'
Any clue why that would be an issue? I'm starting to think it's not related to SC