Hi Mircea,
Which version are you using? When reading (normal or a la MakeClass)
the array counter is set to 0 if the number of array elements was 0.
Rene Brun
On
Fri, 28 Feb 2003, Mircea Coca wrote:
>
> 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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