Differences between KDTREE and DIRECT7

[LandauR]

Hi,

Sorry to bother you. Thanks to your great package, I have ran a version of robot localization successfully with NDT in ndt_omp. During my tests, I found something different in performance between KDTREE and DIRECT7, but I found it difficult to explain.

I ran a diff-driven robot with a 2d laser in a static environment on the same path with same 2d map. I ran my robot with DIRECT7, the laser scan did not match the map well while I ran with KDTREE, the laser scan match better.

Here are two pictures of matching with KDTREE and DIRECT7.

KDTREE match below.

DIRECT7 match below.

I really can not think about a reason to explain this phenomenon. I would be so grateful if you could offer some help on it.

Best regards.

[koide3]

Did you see the same issue with DIRECT1 as well?

[LandauR]

Yes, DIRECT1 performed similar with DIRECT7.

[koide3]

Hmm, can you try a small transformation_epsilon_ to see if it's a problem of convergence parameters? In addition to that, please check if the package is the latest version. Older versions have some problems in line search.

[LandauR]

We have just found whrere the problem is. It turns out it has noting to do with search method.

[hiyyg]

We have just found whrere the problem is. It turns out it has noting to do with search method.

May I ask what the actual problem is?