[WIP] Pybind version (Working, tested on Mac and Linux)

[ProfFan]

This is a working version of the demo project for Pybind11 based wrapping.

Compiling

• First compile GTSAM with pybind wrapper. This can be done by cloning the feature/new_wrapper branch of GTSAM, and compile the branch with -DGTSAM_BUILD_PYTHON=ON -DGTSAM_TYPEDEF_POINTS_TO_VECTORS=ON.
• Make sure that your system is clean (THIS IS VERY IMPORTANT!!!!)
  • I wasted hours on this mysterious issue that gtsam_example does not accept GTSAM objects
  • Turns out that I have another install of GTSAM cython wrapper that is loaded instead of the pybind version
  • I always uninstall by pip3 uninstall gtsam, so what is the problem?
  • pip will only uninstall the first copy, so if you somehow have two gtsams installed...
  • to fool proof, run pip3 uninstall gtsam again to make absolutely sure.
• Clone this repo and checkout feature/pybind branch.
• mkdir build, cd build
• cmake .. -DCMAKE_PREFIX_PATH="/home/fan/Projects/CV/SLAM/gtsam_install/lib/cmake" -DGTSAM_EXAMPLE_BUILD_PYTHON=ON -DCMAKE_INSTALL_PREFIX=../example_install (change as needed)
• make install
• cd ../example_install/python
• python3 setup.py install --user

Now you should be able to run the tests.

[dellaert]

I think we should axe the examples and tests and make this a MVE (minimal viable example).

@ProfFan I agree. Why do we have all those examples and tests here? I vote for one class in c++, one c++ test, it being wrapped, one test in python, and one main python file with argparse.

[varunagrawal]

@ProfFan so I will let you merge this in, then I can get to work rebasing and adding my changes to this repo. I have some neat tricks to make this more tutorial-esque. :slightly_smiling_face: