This is an old revision of the document!
When trying to access the extra-info field for a track, it may happen that it is not filled. This can get annoying f. ex. when dumping an nTuple, where only the standard value is filled, like:
tuple->column( head+"_TrNExpectedTT", track->info(LHCb::Track::nExpectedTT, -100.) );
The extra-info field is filled in the algorithm “TrackAddLikelihood” in “TrackAddExtraInfoSeq”.
TrackAddLikelihood("TrackAddLikelihood").inputLocation = "Rec/Track/Forward"
Note the LOWERCASE “i” of “inputLocation”!
This should solve the problem.