std::out_of_range of FixedLagSmoother methods

[HeXu1]

Hi,
I have test BatchFixedLagSmoother and IncrementalFixedLagSmoother method to fuse imu and lidar data with gtsam::CombinedImuFactor and addExpressionFactor factors.

I have built the latest gtsam from source they all have bug when they start fixedlagsmooth,
the BatchFixedLagSmoother method output is:
terminate called after throwing an instance of 'std::out_of_range'
what(): map::at

and the IncrementalFixedLagSmoother method output is:
terminate called after throwing an instance of 'std::out_of_range'
what(): invalid key

hope for your reply, thanks.

[HeXu1]

and I don't know how to output debug information like #1092
[DEBUG] (2022-02-03 16:13:45.949) OptimizerGTSAM.cpp:101::optimize() Optimizing graph...
[DEBUG] (2022-02-03 16:13:45.949) OptimizerGTSAM.cpp:146::optimize() hasGPSPrior=false
[DEBUG] (2022-02-03 16:13:45.949) OptimizerGTSAM.cpp:164::optimize() fill poses to gtsam...

[RomanStadlhuber]

I just want to chip in and say that I am experiencing the same issue.

Here is a minimal example to reprocude this problem.
While there are existing issues like #1092 where this problem seemingly occurs at random, I have consitently observed this problem to occur whenever I am adding timestamps that exceed the smoother lag.

While my example above was created by piecing together parts of the preintegration and FixedLagSmoother examples respectively, it might be worth mentioning that the FixedLagSmoother example constructs a minimal problem where factors are only added up to the lag time, leaving open the question if there is any further logic that needs to be called after the smoothers window is "full"?

Maybe the author of that example, @svwilliams knows more about that.

Kind regards.