Re: trying to get tpm1 vertex

From: Stephen J. Sanders (ssanders@ukans.edu)
Date: Sat Mar 31 2001 - 13:04:54 EST

  • Next message: Stephen J. Sanders: "mult updates"

    Hi,
    
    With Bjorn's statement that it could be done, and Peter's earlier
    identification of the const problem, I tried a little harder to get
    things working with ROOT 3.00.06.
    
    And succeeded!
    
    However, I think I found a possible programming bug in
    BrTPCClusterFinder.cxx that I'd like to ask the experts to look at:  As far
    as I can tell, fClusterIdTable is not initialized unless it has been
    previously used, and then only the previously used elements are
    reset.  I was able to trace my
    segfault situation to an attempt at accessing one of the uninitialized
    elements of this array.  I know from past experience that gcc on the
    linuxPPC platform does not automatically initialize memory...this may be
    different on Intel boxes.   In any case, by  explicitly setting the elements
    of this array to -1 in the Init() member, everything seems to work fine.
    
    ...steve
    
    > 
    > Hi Steve. I don't have much to add on the cluster side, other than to say
    > that I have succesfully used BRAT 1-15-1 with ROOT 3.00.06 for full
    > reconstruction including clustering and vertexing with TPM1. It should not
    > be a compatibility problem...
    > 
    > About the veretx, I can say that the code you sent looks very good. The
    > important thing is not to forget the cuts that Hiro sent you - otherwise
    > the vertex just isn't good. I personally use
    > a.  z_error <0.8
    > b.  z_sigma <2
    > when I have good statistics, but this does not make a major difference.
    > 
    > Good luck :-)
    



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