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/data/refman/pasoursint/CMSSW_5_3_6/src/HiggsAnalysis/CombinedLimit/interface/th1fmorph.h

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00001 #include "TH1.h"
00002 
00003 TH1F *th1fmorph(const char *chname, 
00004                 const char *chtitle,
00005                 TH1F *hist1,TH1F *hist2,
00006                 Double_t par1,Double_t par2,Double_t parinterp,
00007                 Double_t morphedhistnorm,
00008                 Int_t idebug=0) ;
00009 TH1D *th1fmorph(const char *chname, 
00010                 const char *chtitle,
00011                 TH1D *hist1,TH1D *hist2,
00012                 Double_t par1,Double_t par2,Double_t parinterp,
00013                 Double_t morphedhistnorm,
00014                 Int_t idebug=0) ;
00015   //--------------------------------------------------------------------------
00016   // Author           : Alex Read 
00017   // Version 0.2 of ROOT implementation, 08.05.2011
00018   // *
00019   // *      Perform a linear interpolation between two histograms as a function
00020   // *      of the characteristic parameter of the distribution.
00021   // *
00022   // *      The algorithm is described in Read, A. L., "Linear Interpolation
00023   // *      of Histograms", NIM A 425 (1999) 357-360.
00024   // *      
00025   // *      This ROOT-based CINT implementation is based on the FORTRAN77
00026   // *      implementation used by the DELPHI experiment at LEP (d_pvmorph.f).
00027   // *      The use of double precision allows pdf's to be accurately 
00028   // *      interpolated down to something like 10**-15.
00029   // *
00030   // *      The input histograms don't have to be identical, the binning is also
00031   // *      interpolated.
00032   // *
00033   // *      Extrapolation is allowed (a warning is given) but the extrapolation 
00034   // *      is not as well-defined as the interpolation and the results should 
00035   // *      be used with great care.
00036   // *
00037   // *      Data in the underflow and overflow bins are completely ignored. 
00038   // *      They are neither interpolated nor do they contribute to the 
00039   // *      normalization of the histograms.
00040   // *
00041   // * Input arguments:
00042   // * ================
00043   // * chname, chtitle : The ROOT name and title of the interpolated histogram.
00044   // *                   Defaults for the name and title are "THF1-interpolated"
00045   // *                   and "Interpolated histogram", respectively.
00046   // *
00047   // * hist1, hist2    : The two input histograms.
00048   // *
00049   // * par1,par2       : The values of the linear parameter that characterises
00050   // *                   the histograms (e.g. a particle mass).
00051   // *
00052   // * parinterp       : The value of the linear parameter we wish to 
00053   // *                   interpolate to. 
00054   // * 
00055   // * morphedhistnorm : The normalization of the interpolated histogram 
00056   // *                   (default is 1.0).  
00057   // * 
00058   // * idebug          : Default is zero, no internal information displayed. 
00059   // *                   Values between 1 and increase the verbosity of 
00060   // *                   informational output which may prove helpful to
00061   // *                   understand errors and pathalogical results.
00062   // * 
00063   // * The routine returns a pointer (TH1 *) to a new histogram which is
00064   // * the interpolated result.
00065   // *
00066   // *------------------------------------------------------------------------
00067   // Changes from 0.1 to 0.2:
00068   // o Treatment of empty and non-existing histograms now well-defined.
00069   // o The tricky regions of the first and last bins are improved (and
00070   //   well-tested).
00071   // *------------------------------------------------------------------------
00072