Hi,
We found the problem: not checking the number of entries
in the array; root doesn't initialize the array element to some
nonsense number every time reads an event. So if the previous event had 2
electrons and the current event has only one, then the second entry in the
electron array has the second electron values from the previous
event...The weakness of using MakeClass.
Mircea
On Fri, 28 Feb 2003, Jedong Lee wrote:
> I noticed et2 of j=164 and j=165 were the same. It was a length-of-array
> problem, not a bug of CopyTree().
> I realize CopyTree() was smarter than I am.
>
> - Jedong
>
> On Fri, 28 Feb 2003, Jedong Lee wrote:
>
> > Hello,
> >
> > I am stripping off an ntuple with command like this: (ROOT 3.05/00)
> >
> > TTree *small = mmm.fChain->CopyTree("Et[0]>20&&Et[1]>20")
> >
> > By the way, the resulting file contains less events than I expected.
> > I compared the entries and found that not all the events
> > that pass the criteria are written to the target file.
> >
> > This seems to be happening whenever the event(entry = i) passes
> > the cut and event(entry = i+x) also passes, and x is small number..
> >
> > This is the list of variables in two files:
> > ( j=164 and j=165 passes the cut, only j=164 survived.
> > Out of j=175,177,178,179, j=175 and j=178 survived.
> > Out of j=301,302, j=301 survived.)
> >
> > Original file: (showing the events that passes the cut)
> >
> > j 8 et1 101.701 et2 37.4808
> > j 10 et1 39.8504 et2 27.9597
> > j 28 et1 43.283 et2 37.779
> > j 84 et1 45.18 et2 27.6098
> > j 86 et1 40.8786 et2 20.0176
> > j 141 et1 37.3549 et2 22.055
> > j 158 et1 32.8841 et2 20.5765
> > j 164 et1 46.0031 et2 29.4996
> > j 165 et1 38.1034 et2 29.4996
> > j 175 et1 70.7513 et2 31.3695
> > j 177 et1 32.906 et2 31.3695
> > j 178 et1 32.8016 et2 24.8853
> > j 179 et1 22.3331 et2 24.8853
> > j 216 et1 151.5 et2 91.1525
> > j 246 et1 26.6626 et2 20.8906
> > j 257 et1 121.573 et2 72.1682
> > j 267 et1 36.5081 et2 23.0727
> > j 301 et1 40.4186 et2 36.0574
> > j 302 et1 29.8817 et2 36.0574
> > j 334 et1 59.1586 et2 37.6737
> > .
> > .
> > .
> >
> > Target file: (all the events in the target)
> >
> > j 0 et1 101.701 et2 37.4808
> > j 1 et1 39.8504 et2 27.9597
> > j 2 et1 43.283 et2 37.779
> > j 3 et1 45.18 et2 27.6098
> > j 4 et1 40.8786 et2 20.0176
> > j 5 et1 37.3549 et2 22.055
> > j 6 et1 32.8841 et2 20.5765
> > j 7 et1 46.0031 et2 29.4996
> > j 8 et1 70.7513 et2 31.3695
> > j 9 et1 32.8016 et2 24.8853
> > j 10 et1 151.5 et2 91.1525
> > j 11 et1 26.6626 et2 20.8906
> > j 12 et1 121.573 et2 72.1682
> > j 13 et1 36.5081 et2 23.0727
> > j 14 et1 40.4186 et2 36.0574
> > j 15 et1 59.1586 et2 37.6737
> > .
> > .
> > .
> >
> > Best,
> > Jedong
> >
> >
>
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