I am searching for the code chunks with the definitions of
used by xgboost in its Python implementation available at https://github.com/dmlc/xgboost/tree/master/python-package/xgboost (*)
I can derive the above formulae analytically using the original paper by Chen and Guestrin (available at https://arxiv.org/abs/1603.02754 ), but I need a deep dive into code.
Can somebody point out the location of those definition in (*)? After a quick search I found nothing.