Hi Birger, On Thu, 31 Oct 2002, Birger Koblitz wrote: > Hi Rene, > > yes, this is what we would like to have. Sorry for my poor description. > Just two additional clarifications: > - The operator [] should also work in selections: > mytree.Draw("somethingElse","myEventBits[10]"); > Yes, this was implicit in my previous mail. In the selection, mask operations should also be supported, eg mytree.Draw("somethingElse","myEventBits & 0x3ff"); > - Not only calling mytree.Draw("myEventBits"); should produce this > histogram, but also clicking on the variable in the TBrowser. Yes, it is the same logic. TBrowser calls TTree::Draw. OK, we will implement this logic. Could you send me a small TTree file (not HAT file) that we could use to test the new feature? Rene Brun > > Cheers, > Birger > > > On Thu, 31 Oct 2002, Rene Brun wrote: > > > Hi Birger, > > > > Let see if I understand correctly your request. > > > > - you are requesting an operator [] to get the ith bit in a TBits > > instead of calling the function TestBitNumber(). > > That is quite easy to implement. I propose in this case > > a read only operator []. > > > > - you want to do mytree.Draw("myEventBits"); > > This will automatically loop on all your events and filling > > an hitogram with as many channels as there are bits in TBits > > and where the bin count is incremented by 1 or the specified weight > > for each event where the corresponding bit is set. > > This requires a bit more work, but I agree would be a nice addition. > > > > Rene > > > > On Thu, 31 Oct 2002, Birger Koblitz wrote: > > > > > Hi Rene, > > > > > > I think Ursula Berthon already talked to you about this at the > > > Root-Meeting: > > > > > > Within H1 we would like to be able to put bit-arrays into our HAT tree > > > which should be accessible using only a browser and which is used for > > > event selection. Currently TBits allows to use the member function > > > TestBitNumber() which is quite inconvenient if it comes to a selection of > > > a large number of status bits e.g. to check if the quality of an event is > > > good. This could easily go over the maximum selection length of a tree. > > > Therefore it would be nice if one could simply use bits[i] to check the > > > ith bit in TBits bits. In addition it would be nice if one could view a > > > bit-array in a TBrowser. It should show a histogram over the bits and the > > > number of entries per bit. Currently fAllBits shows the entries (in 2^i > > > form) for the lowest byte. I think this is not really useful. > > > > > > In the moment we are using byte-arrays which at least allow to use the [] > > > operator and allow us to inspect one bit with the TBrowser. H1 would be > > > very intersted to move to TBits because currently the bit-arrays make up > > > most of our HAT ntuple, we would be even willing to move to a newer > > > root-version ;-) > > > > > > Cheers, > > > Birger > > > > > > ------------------------------------------------------------ > > > Birger Koblitz koblitz@mail.desy.de > > > MPI für Physik > > > c/o DESY-FH1 Tel: +49 40 8998-2431 > > > Notkestr. 85 Fax: +49 40 8998-3094 > > > D-22603 HAMBURG > > > > > > > > > ------------------------------------------------------------ > Birger Koblitz koblitz@mail.desy.de > MPI für Physik > c/o DESY-FH1 Tel: +49 40 8998-2431 > Notkestr. 85 Fax: +49 40 8998-3094 > D-22603 HAMBURG >
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