Retire PoseRTV and IMUFactor in unstable

[Frank Dellaert]

PoseRTV and IMUFactor in unstable was an early attempt at dealing with IMUs, but I think it is superseded by the new stuff in navigation. In addition, the treatment of PoseRTV as a Lie group is a bit farfetched and dates from before our switch to Manifolds etc. It continues to cause a lot of work to keep this up to date.

Is there any reason to keep this in GTSAM, @alexgcunningham or @jdong37 or @lucacarlone ?

If we are in agreement, and it is not needed in DDFSAM, I propose we simply remove it. If it is needed in DDFSAM, I propose @jdong37 moves it there. In any case, we should only do this after the large traits refactor has been merged in, but I wanted to create the issue and start the discussion.

[Jing Dong]

That's needed in DDFSAM, move it in DDFSAM won't be hard.

[Frank Dellaert]

Hi @jdong37 you could move this now, then close this issue...

[Alex Cunningham]

I'm in the process of moving some of the things that I had ported from DDFSAM. There's also Pose3Upright, BearingS2 and a couple of simulation-specific geometry elements that are likely unused. Pose3Upright might actually be useful for some things, though BearingS2 is likely superseded by something else at this point.

My plan at the moment is to retire all of the dynamics that had been involved with DDFSAM, since it largely didn't work.

[Frank Dellaert]

is BearingS2 like Unit3 ? And, I have a change outstanding to PoseRTV etc, so hold on until that is merged (in a few moments)

[Alex Cunningham]

On closer inspection, BearingS2 is exactly like Unit3, though probably not correctly implemented. I'll also move it out to ddfsam.

Is there anyone that wants Pose3Upright? It'd be a good model to use for simplified 3D environments, or for reference frame transforms in applications with shared gravity vectors. It'll need some updates to match the newer interfaces, but otherwise could be useful. I can also move out SimWall2D and SimPolygon2D, which were used to do the random generation of scenarios that I used for 2D cases.

[Alex Cunningham]

Does anyone use the PartialPriorFactor that is in gtsam_unstable? I'd like to update all of the code for ddfsam to not rely on gtsam_unstable, and this is the only remaining code that DDFSAM relies on. I'm prepping a branch that removes PoseRTV, BearingS2, Pose3Upright, SimWall2D, SimPolygon2D and any required factors.

[Chris Beall]

VO still references it, but we no longer need it. I use PoseTranslationPrior instead. Fine to remove as far as I'm concerned.

[Alex Cunningham]

It could just get moved to stable as an option as well.

[Frank Dellaert]

Hold on on removing PoseRTV - it's linked with something I'm doing. If it is unit tested to your taste it can be moved to gtsam/slam as far as I'm concerned. I might move it later to sam as an expression factor.

[Alex Cunningham]

You mean PartialPriorFactor? My old unit tests poked most of the test cases I knew about, though I suspect it could be turned into an expression factor. It does turn out that the unit tests were actually based around the PoseRTV dynamics constraints, so I'll need to create some more generic unit tests.