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Also worth a read: Report on the SIGIR 2015 Workshop on Reproducibility, Inexplicability, and Generalizability of Results (RIGOR)
In short, it looks like there's been recent work to develop an evaluation framework around Lucene. We have some support for this in ir-utils, but it wasn't widely used (we've always used the Indri implementation for consistency). So we have a choice – work with the lucene4ir workshop code, which is open source but primarily developed for a single workshop. Or continue working in ir-utils, since that what we've got. In this case, we'd need to extend ir-utils to have improved support for Lucene similarities.
Other notes
Re-reading Zhai's SLMIR, noticed different ranges for Okapi BM25 parameters.
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