Hello, -> I used differential calculus well and was able to greatly improve the upper bound on DPH. I have explained the method in the documentation. The PR for this code accidentally has many other commits too. The commit to merge is :- https://github.com/xapian/xapian/pull/42 -> I tested it using automated tests on my machine and there is a noticeable difference in it's value. -> The factor related changes to InL2,IneB2,IfB2 and the PR for DLH can also be merged. Regards Aarsh -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.xapian.org/pipermail/xapian-devel/attachments/20140614/539fe07d/attachment.html>