> Suppose there is a given program, which is basically running. After
> some time you find that there is some need for histogramming data
> within this program, which can principally done using root. What are
> the option for implementing root functions without changing more
> than adding a few lines in the source code and adding diverse libs
> and so on in the makefile?
>
The "test" subdirectory from our distribution contains the
hsimple.cxx file and makefile to build it.
I hope it can be used as pattern to start with.
The source of that program looks as follows. But I'd like to highlight
It is assumed one needs no interaction (drawing is a kind of the
interaction too) with his data. It is a "pure" batch job. Then one
can explore the data file been created with the interactive ROOT
session later.
Valery
PS. Please, always fill "Subj" field of your E-mail sending it to
"roottalk" list.
//*CMZ : 1.00/00 17/02/97 16.44.11 by Fons Rademakers
//*-- Author : Rene Brun 19/08/96
//______________________________________________________________________________
//*-*-*-*-*-*-*Simple examples with histograms created/filled and saved*-*-*-*
//*-* ========================================================
//*-*
//*-* This program creates :
//*-* - a one dimensional histogram
//*-* - a two dimensional histogram
//*-* - a profile histogram
//*-* - an ntuple
//*-*
//*-* These objects are filled with some random numbers and saved on a file.
//*-*
//*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
#include "TROOT.h"
#include "TFile.h"
#include "TH1.h"
#include "TH2.h"
#include "TProfile.h"
#include "TNtuple.h"
#include "TRandom.h"
//______________________________________________________________________________
main(int argc, char **argv)
{
TROOT simple("simple","Test of histogramming and I/O");
// Create a new ROOT binary machine independent file.
// Note that this file may contain any kind of ROOT objects, histograms,
// pictures, graphics objects, detector geometries, tracks, events, etc..
// This file is now becoming the current directory.
TFile hfile("hsimple.root","RECREATE","Demo ROOT file with histograms");
// Create some histograms, a profile histogram and an ntuple
TH1F *hpx = new TH1F("hpx","This is the px distribution",100,-4,4);
TH2F *hpxpy = new TH2F("hpxpy","py ps px",40,-4,4,40,-4,4);
TProfile *hprof = new TProfile("hprof","Profile of pz versus px",100,-4,4,0,20);
TNtuple *ntuple = new TNtuple("ntuple","Demo ntuple","px:py:pz:random:i");
// Fill histograms randomly
Float_t px, py, pz;
for ( Int_t i=0; i<10000; i++) {
gRandom->Rannor(px,py); //px and py will be two gaussian random numbers
pz = px*px + py*py;
Float_t random = gRandom->Rndm(1);
hpx->Fill(px);
hpxpy->Fill(px,py);
hprof->Fill(px,pz);
ntuple->Fill(px,py,pz,random,i);
}
// Save all objects in this file
hfile.Write();
// Close the file. Note that this is automatically done when you leave
// the application.
hfile.Close();
return 0;
}
=================================================================
Dr. Valery Fine Telex : 911621 dubna su
-----------
LCTA/Joint Inst.for NuclearRes Phone : +7 09621 6 40 80
141980 Dubna, Moscow region Fax : +7 09621 6 51 45
Russia mailto:fine@main1.jinr.dubna.su
mailto:fine@vxcern.cern.ch
Dr. Valeri Faine
------------ Phone: +41 22 767 6468
CERN FAX : +41 22 782 2601
CH-1211 Geneva, 23 mailto:fine@vxcern.cern.ch
Switzerland http://nicewww.cern.ch/~fine