Histos in different directories

Nick van Eijndhoven (Nick@fys.ruu.nl)
Tue, 3 Mar 1998 15:16:09 +0100 (MET)

Dear ROOTers,
I have a file which contains various histograms.
I have a private class which I want to access that histo file and
in a new histo "test" I want to place the sum of h1 and h2, where h1
and h2 are two histos of the histogram file.
In my private class I have declared

public :
TH1F* test;

private :
TFile* f;

whereas in the code of my class I do :

f=new TFile("data.root");
test=new TH1F(.........); // ... represent the usual arguments
test->Add(h1,h2);

The result is that in my browser I see under ROOT files indeed the
file "data.root" with all the original histograms and also the new
histo "test".
However, I would like to have the histo "test" present in the "memory
mapped files" which appears in my browser.
How can I achieve that ?

Thanks,
Nick.

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Dr. Nick van Eijndhoven Department of Subatomic Physics
email : nick@fys.ruu.nl Utrecht University / NIKHEF
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WWW : http://www.fys.ruu.nl/~nick Office : Ornstein lab. 172
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