I noticed that @jihoonl opened the PR #726 which performs a similar thing. As discussed in googlecartographer/cartographer_ros#613 (@cschuet has already taken a look), I pulled this out of #481 (a really old PR whose merging has been postponed), which is an example where re-running optimization is triggered from elsewhere as well (besides from `ComputeConstraintsForNode`). This refactoring makes libcartographer friendlier for use cases such as that one.
An important detail is that I have changed the condition in `WaitForAllComputations` to also check if the work queue is empty. If there are other things on the worker queue besides `ComputeConstraintsForNode`, currently we will wrongfully conclude that all computations are done. (This detail was merged in #754, so it's no longer in the diff of this PR).
Also missing is the same thing for 3D. I can add that when we settle on this.
Also, I suggest that `run_loop_closure` gets renamed to `run_optimization`.
Christoph Schütte
Juraj Oršulić
Jihoon Lee
Wolfgang Hess