Build for Eigen5

[nmarticorena]

Hi all,

Again, in an effort to keep libfranka available in conda-forge, I needed to update the CMake configuration to be compatible with Eigen5.

Overall, the only breaking change of Eigen5 is introduced here cmake: remove deprecated package config variables. This breaks the line:

libfranka/cmake/FindEigen3.cmake

Line 7 in 9f9304e

REQUIRED_VARS EIGEN3_INCLUDE_DIRS

given that package config variables have now been deleted.

This issue comes with a accompanying PR to solve this issue, I would appreaciated any comment and if there is any interested to merge those changes.

Notes:
Eigen 5.0.0 release notes

[AndreasKuhner]

Hi @nmarticorena ,
thanks for reaching out. I will have a look on the change or do you already know if this works with ubuntu 20, 22 and 24? (our current supported platforms).

Looking at the 'native' eigen versions, we would have the 3.3.x for 20 and 3.4 for 22 and 24 -> Why do you want to go for 3.5 aka 5.0?

Cheers,
Andreas

[nmarticorena]

Hi @AndreasKuhner, thanks for taking the time to check the issue/PR.

I will have a look on the change or do you already know if this works with ubuntu 20, 22 and 24? (our current supported platforms).

I have only tested it on Ubuntu 20.04 so far, where it works as intended. This should not break compatibility with Eigen 3.3 or Eigen 3.4, since Eigen3::Eigen is available there as well.

Looking at the 'native' eigen versions, we would have the 3.3.x for 20 and 3.4 for 22 and 24 -> Why do you want to go for 3.5 aka 5.0?

In retrospect, the PR title and issue may not be ideal: the goal is not to require or move libfranka to Eigen 5.0.0. It is more about allowing compilation with newer Eigen versions while keeping the current Eigen 3.x use cases working as before.

The change follows Eigen’s intended CMake usage through the imported target, as documented already in the Eigen 3.3 CMake docs, and avoids relying on deprecated CMake variables that were removed in Eigen 5.

The motivation is mostly conda-forge related, where some robotics packages are starting to support newer Eigen versions (e.g, Pinocchio).

Happy to discuss further and thanks for your time!