confusing about test error about distributed-mapper

[itzsid]

Hi @lantianran,

1. It is the linearized error given all the constraints in the pose graph. graph.error(estimate) returns that. You can think of it as the sum of all the constraint errors between relative pose constraints and the estimate. Checkout https://gtsam.org/tutorials/intro.html for more details on what graph.error(...) represents. Ideally for distributed optimizer, the error should be the same as centralized two stage. Centralized two stage + GN represents running a few gauss-newton iteration starting from centralized 2 stage estimate.
2. I do not have GT saved for this dataset. One solution is to assume the centralized estimator's output as the GT and compare against that. Another solution is to create your own synthetic dataset with noisy constraints and use that.
3. Yes, a vertex only belongs to one robot, so you concatenate each robot's estimate to get the final centralized estimate.

Let me know if it's not clear.
Thanks!

[NatureLan-sudo]

Thank you so much for your kind help. I have been sick recently and I'm sorry to get back to you so late. After your explanation, I have fully understood.