You can not just use the model output from Ranklib.
I opened this issue few months ago but I never had the right
time/motivation to implement it [1] .
You need to convert it in the Apache Solr LTR expected format.
I remember a script should be available[2]

[1]  https://sourceforge.net/p/lemur/feature-requests/144/

[2] https://github.com/ryac/lambdamart-xml-to-json

--------------------------
Alessandro Benedetti
Search Consultant, R&D Software Engineer, Director
www.sease.io

On Thu, Feb 15, 2018 at 3:55 PM, Brian Yee <[EMAIL PROTECTED]> wrote: