cmake error when building with MATLAB flag ON

[izzys]

CMake Error at cmake/GtsamMatlabWrap.cmake:106 (message):
You must call find_package(GTSAM) before using wrap
Call Stack (most recent call first):
cmake/GtsamMatlabWrap.cmake:59 (wrap_library_internal)
gtsam/CMakeLists.txt:214 (wrap_and_install_library)

[varunagrawal]

This seems like GTSAM was either not built first or is installed somewhere which is not on your PATH.

Which OS are you on?

[izzys]

Linux 16.04

I had a gtsam installation without MATLAB that went fine. Then I tried to build again with the MATLAB flag ON, and the build failed.

So I cleaned the previous installation, removed all files from usr/local and started all over again.

I still get the error above.

Now I am building again without the MATLAB flag, and it is going fine.

[varunagrawal]

Okay I can reproduce this. I'll see what the issue is.

[jlblancoc]

@varunagrawal Let me know if you suspect it's related to any of the recent changes to cmake.

I don't have any Linux partition with MATLAB installed (for some reason, always preferred Windows for matlab), but if needed to debug this, could give it a try.

[varunagrawal]

@jlblancoc seems like this commit broke something. I am able to build the MATLAB wrapper on commits before this.

I'm looking into it some more to try and isolate the issue.

[varunagrawal]

I found the problem.

In gtsam/CMakeLists.txt you are setting the project name again with project(gtsam LANGUAGES CXX). The project name should be GTSAM aka uppercase, which is why the check at L102 of GtsamMatlabWrap.cmake is failing (it is checking for GTSAM but the project name has been set to gtsam aka lowercase), and hence it goes to the else condition and fails because GTSAM_INCLUDE_DIR is never set explicitly in the cmake files.

The fix should be super simple: Update gtsam/CMakeLists.txt to set the project to GTSAM so that we are consistent, and then update GtsamMatlabWrap.cmake to check for lowercase or uppercase always.

@izzys thanks again for submitting the issue. We should have this resolved by tomorrow.

[varunagrawal]

@dellaert you should take a look at this issue. This is why we really need to figure out CI for Matlab. Maybe contact Mathworks about this?

[jlblancoc]

Thanks for investigating it!

But please, don't change it to GTSAM, it's like that for a reason (undoing it will break Windows builds).

Why not updating GtsamMatlabWrap to check for lowercase only? Can you try it? Thanks

[cntaylor]

I had this same problem. I fixed this (see github cntaylor/gtsam, about to submit a pull request...) by modifying line 102 in GtsamMatlabWrap to check for "gtsam" rather than "GTSAM"