Parallelization executes independent computations concurrently across processing resources. In XGBoost, column blocks divide features so each boosting model can use multiple CPU cores, reducing training time. section 5.4.2
Use the distinction between parallel work and sequential model construction:
- Parallelize split-finding across feature columns and processor cores within each model. section 5.4.2
- Keep boosting iterations sequential because each model uses the previous model’s results. section 5.4.2
- Do not confuse this with training multiple independent models simultaneously, as in random forests. section 5.4.2





































