MantisBT - JANA
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0000273JANAFeature Requestpublic2012-07-31 09:042012-08-14 23:13
davidl 
davidl 
normalminorN/A
resolvedfixed 
0000273: Add status word to JEvent
Tracking code for GlueX ran into some memory limitations for very busy events. The solution was to put a cap on the number of track candidates it would try and process. If more than the limit appear, then all are thrown away since the event is considered unreconstructable as far as tracking is concerned.

There needs to be a simple way for a tracking factory to indicate that it failed so other code downstream can distinguish this condition from when no track candidates are found.

To do this, JANA should implement a generic status word (32bit or 64bit) that is kept in JEvent and that the user can use to communicate this type of info efficiently. It will be left to the user to assign meaning to each of the bits. Methods to set and get bits should be available in both JEvent and JEventLoop to make it easy for factories to access the facility.

We may also want to add a facility to add a description to each of the bits to make it easy to display and even record in the header of the output file in the event that the bit assignments change. This would, however, make mixing files problematic since the descriptions in two files may not match. That could be left to the JEventSource/JEventSink implementors though.
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Issue History
2012-07-31 09:04davidlNew Issue
2012-08-14 23:13davidlNote Added: 0000426
2012-08-14 23:13davidlStatusnew => resolved
2012-08-14 23:13davidlResolutionopen => fixed
2012-08-14 23:13davidlAssigned To => davidl

Notes
(0000426)
davidl   
2012-08-14 23:13   
This fix was committed with revision 1009. It has not been tested.

One issue with this mechanism though is that the status word changes as factories are called. This means one needs to guarantee that a certain factory was called in order for a status bit to be valid.