Re: [ROOT] Making a chain from a file list.

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thanks.




On Thu, 29 Apr 2004, Rene Brun wrote:

> Drew,
> 
> Three ways, assuming Myclass.h and Myclass.C
> 
> 1- you have a TChain chain object
>    root > .L Myclass.C
>    root > Myclass a(&chain)
>    root > a.Loop()
>    root > chain.Delete()Drew Alton wrote:
> 
> 2- you have a pointer to a TChain* chain
>    root > .L Myclass.C
>    root > Myclass a(chain)
>    root > a.Loop()
>    root > delete chain;
> 
> 3- you have to use the chain definitions as it was when you ran makeClass
>    root > .L Myclass.C
>    root > Myclass a
>    root > a.Loop()
> 
> Rene Brun
> 
>  
> > Hi,
> >    Maybe its' just too early in the morning for me...but I didnt follow
> > how that would let me change from one list of files to another.
> >    So yes I have a Myclass.h and Myclass.C set of files.  They were
> > generated from a chain that included set1_file1.root, set1_file2.root,
> > etc.  Now I would like to make them use set2_file1.root, set2_file2.root,
> > etc.
> >    are you saying I just make a new chain, and I pass it in as &chain?
> >                                              -Drew
> > 
> > On Thu, 29 Apr 2004, Rene Brun wrote:
> > 
> > > Hi Drew,
> > >
> > > Assuming that you have Myclass.h and Myclass.C (the two files generated
> > > by MakeClass) and a TChain chain object, do
> > > root > .L Myclass.C
> > > root > Myclass a(&chain)
> > > root > a.Loop()
> > > root > chain.Delete()
> > >
> > > Rene Brun
> > >
> > > Drew Alton wrote:
> > > >
> > > > Hello,
> > > >    I am running over a large number of root-tuples and skimming out the
> > > > events I want to keep.
> > > >    Given the number of files and events I have I want to keep some
> > > > separations.
> > > >    My general plan is to chain a list of files from the same data set,
> > > > use MakeClass to make a class, which will skim out the ones of interest
> > > > to me.  Then repeat it for each data set.  Since all the data sets have
> > > > the same format, the same make class could be used, except that the .h
> > > > file will have the wrong list of root tuples.  In the past I've just
> > > > changed this by hand, but it occures to me that it ought to be possible
> > > > at run time to read a file which contains the list of files to chain
> > > > together.
> > > >    Has anyone ever done this...have any examples?
> > > >    Thanks for the help.
> > > >                                               -Drew
> > >
> 

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