[Xapian-devel] [GSOC 2014] Some questions about Letor module

Jiarong Wei vcamx3 at gmail.com
Sun Mar 9 00:36:54 GMT 2014


I've read the code of letor module. And I have some questions about it:

1. In https://github.com/rishabhmehrotra/xapian/blob/master/xapian-letor/letor_internal.cc#L299, there is a write_to_file method, which save RankList into “train.txt”. But the format for “train.txt” is different from the one mentioned in http://trac.xapian.org/wiki/GSoC2011/LTR/Notes#QueryLevelNorm. And in https://github.com/rishabhmehrotra/xapian/blob/master/xapian-letor/letor_internal_refactored.cc#L716, Qid and DocID become optional. What format should we use for “train.txt”? Is there any sample “train.txt” available?

2. In http://trac.xapian.org/wiki/GSoC2011/LTR/Notes#QueryLevelNorm, it mentioned "the first column is the relevance judgement”. I think the value of the relevance judgement is just 0 or 1. But the code saves it as a “double”. Is it just for convenience? Or I misunderstand the whole thing?

3. I’ve got qrels file of INEX 2010, but I can find query file. How can I get it? I can’t find it on INEX website. 

Thank you!

Jiarong Wei
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