improvement not obvious?

[yezhengli-Mr9]

improvement not obvious? Since BM25

Total hits: 11151 out of 15675, which is 0.7113875598086125
Precision: 0.11151
Average precision: 0.1115100000000054
Average recall: 0.8321873943359426

BM42

Total hits: 11488 out of 15675, which is 0.7328867623604466
Precision: 0.11488
Average precision: 0.11488000000000238
Average recall: 0.8515208038970792

while with

python index_bm25.py

python evaluate-bm25.py

even can sometimes get

Total hits: 12064 out of 15675, which is 0.7696331738437001
Precision: 0.12064
Average precision: 0.12063999999999798
Average recall: 0.8949703861174952