Lau2DSplineDPPdf.cc

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// Copyright University of Warwick 2004 - 2013.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

// Authors:
// Thomas Latham
// John Back
// Paul Harrison

#include <iostream>

#include "TAxis.h"
#include "TH2.h"
#include "TRandom.h"
#include "TSystem.h"

#include "Lau2DSplineDPPdf.hh"
#include "Lau2DCubicSpline.hh"
#include "LauDaughters.hh"
#include "LauKinematics.hh"
#include "LauRandom.hh"

ClassImp(Lau2DSplineDPPdf)


Lau2DSplineDPPdf::Lau2DSplineDPPdf(const TH2* hist, LauKinematics* kinematics, const LauVetoes* vetoes,
                Bool_t fluctuateBins, Bool_t useUpperHalfOnly, Bool_t squareDP) :
        Lau2DAbsHistDPPdf(kinematics,vetoes,useUpperHalfOnly,squareDP),
        spline_(0)
{
        //We may need to modify the histogram so clone it
        TH2* tempHist(hist ? dynamic_cast<TH2*>(hist->Clone()) : 0);

        if ( ! tempHist ) {
                std::cerr << "ERROR in Lau2DSplineDPPdf constructor : the histogram pointer is null." << std::endl;
                gSystem->Exit(EXIT_FAILURE);
        }

        if (fluctuateBins) {
                this->doBinFluctuation(tempHist);
        }

        spline_ = new Lau2DCubicSpline(*tempHist);

        // Calculate the PDF normalisation.
        this->calcHistNorm();

        // Also obtain the maximum height
        this->calcMaxHeight(tempHist);

        delete tempHist;
}

Lau2DSplineDPPdf::~Lau2DSplineDPPdf()
{
        delete spline_;
        spline_ = 0;
}

Double_t Lau2DSplineDPPdf::interpolateXYNorm(Double_t x, Double_t y) const
{
        // Get the normalised interpolated value.
        Double_t value = this->interpolateXY(x,y);
        return value/norm_;

}

Double_t Lau2DSplineDPPdf::interpolateXY(Double_t x, Double_t y) const
{
        // This function returns the interpolated value of the histogram function
        // for the given values of x and y by finding the adjacent bins and extrapolating
        // using weights based on the inverse distance of the point from the adajcent
        // bin centres.
        // Here, x = m13^2, y = m23^2, or m', theta' for square DP co-ordinates

        // If we're only using one half then flip co-ordinates
        // appropriately for conventional or square DP
        getUpperHalf(x,y);

        // First ask whether the point is inside the kinematic region.
        if (withinDPBoundaries(x,y) == kFALSE) {
                std::cerr << "WARNING in Lau2DSplineDPPdf::interpolateXY : Given position is outside the DP boundary, returning 0.0." << std::endl;
                return 0.0;
        }

        return spline_->evaluate(x,y);

}

void Lau2DSplineDPPdf::calcHistNorm()
{
        norm_ = spline_->analyticalIntegral();
}