Confused about the changed code especially LocalMapping

[ns15417]

HI, First, thank you so much for your code, and i run it very well now but still confused about several parts. I found that you changed the code for many places like the one in Optimizer.cc : you change the function GlobalBundleAdjustmentNavStatePRV() to GlobalBundleAdjustmentNavState() , and in this function you delete the optimization of velocity and add more updates;
Also in the LocalMapping,cc inside the function TryInitVIO() when the computation for IMU
is finished, you delete so many code which is more than the repeative update of keyframes and mappoints. I am confused about this part, cuz you also delete the globalBA: Optimizer::GlobalBundleAdjustmentNavStatePRV(mpMap,mGravityVec,10,NULL,nGBAKF,false); and the afterwards updates.
Do you have any note for these part or do you have any related blog website ?
Again so much thanks for you project