Questions about loop closure's local point cloud

[Cc19245]

Hi, kim!

Thanks for your great work!

Now I have a question about the code of loop closure's local point cloud in laserPosegraphOptimization.cpp at here.

loopFindNearKeyframesCloud(cureKeyframeCloud, _curr_kf_idx, 0, _loop_kf_idx); // use same root of loop kf idx 
loopFindNearKeyframesCloud(targetKeyframeCloud, _loop_kf_idx, historyKeyframeSearchNum, _loop_kf_idx);

I don't understand why you use the last parameter _loop_kf_idx for all of the targetKeyframeCloud, which of them have the point cloud in their local LiDAR frame. Or maybe I have a misunderstand?

Looking forward to your reply!