THashTable of SuperBranch?

From: Tioukov Valeri (valeri@d500na1.na.infn.it)
Date: Wed Mar 10 1999 - 20:17:13 MET


Hi rooters, 

How to solve in the best way the following problem (I think very common):

I have big bank of events ~30000 and I need the fast access to them by 
the event identifier. 

Now my events are stored in the Tree and it is very convinient for 
analysis. But then I need to get event by it's identifier it is not 
straightforward. One branch (leaf) of the tree is the eventID. So if I 
need to get the event NNNN the obvious way is to loop this branch by all entries 
upto  eventID==NNNN. Due to split algorithme it is not slow, but 
for the big number of events the time penalty is significant especially 
if I need to do this operation 3000 times.

To speedup the process I created for this tree the hashtable keeping the 
special objects with 2 numbers : eventID and Entry. Using this hashtable 
I can fastly find event Entry  by the eventID and then get the 
event from Tree by the Entry.
It works. But this solution seems to me not very elegant. May be in Root
already exists something more automatic? 

Regards
Valeri



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