17th December 2009

Identifying Data in the Event

Data within the Event are uniquely identified by four quantities:

C++ class type of the data

E.g., edm::PSimHitContainer or reco::TrackCollection.

module label

the label that was assigned to the module that created the data. E.g., "SimG4Objects" or "TrackProducer".

product instance label

the label assigned to object from within the module (defaults to an empty string). This is convenient if many of the same type of C++ objects are being put into the edm::Event from within a single module.

process name

the process name as set in the job that created the data

14th December 2009

Trying to do things `properly' : rather than use an EDAnalyzer to dump floats to a straight-forward ROOT tree, I am trying to use an EDProducer to store more complex objects that can then be analysed in FWLite. The producing part of this seems to be no trouble, however when I try to access the branch in FWLite, I see messages like :

Error: Symbol G__exception is not defined in current scope  (tmpfile):1:
Error: type G__exception not defined FILE:(tmpfile) LINE:1
Extra Superclusters = (void)0

There does not appear to be much guidance on the web about this, beyond saying that the exception isn't being handled correctly.

Perhaps I am not doing everything in FWLite in the correct order - it seems a bit delicate in that things need to be loaded in a specific way so it can create dictionaries for each class.

Hmm, turns out that the Handle isn't valid - I follow the examples given in WorkBookFWLiteExamples though....

-- DavidWardrope - 14-Dec-2009