LauParametricStepFuncPdf.cc

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/*
Copyright 2008 University of Warwick

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

/*
Laura++ package authors:
John Back
Paul Harrison
Thomas Latham
*/

/*****************************************************************************
 * Class based on RooFit/RooParametricStepFunction.                          *
 * Original copyright given below.                                           *
 *****************************************************************************
 * Authors:                                                                  *
 *   WV, Wouter Verkerke, UC Santa Barbara, verkerke@slac.stanford.edu       *
 *   DK, David Kirkby,    UC Irvine,         dkirkby@uci.edu                 *
 *                                                                           *
 * Copyright (c) 2000-2005, Regents of the University of California          *
 *                          and Stanford University. All rights reserved.    *
 *                                                                           *
 * Redistribution and use in source and binary forms,                        *
 * with or without modification, are permitted according to the terms        *
 * listed in LICENSE (http://roofit.sourceforge.net/license.txt)             *
 *****************************************************************************/


#include <iostream>
#include <vector>
using std::cout;
using std::cerr;
using std::endl;
using std::vector;

#include "TMath.h"
#include "TSystem.h"

#include "LauConstants.hh"
#include "LauParametricStepFuncPdf.hh"

ClassImp(LauParametricStepFuncPdf)


LauParametricStepFuncPdf::LauParametricStepFuncPdf(const TString& theVarName, const vector<LauAbsRValue*>& params, const vector<Double_t>& limits, NormBin normalisationBin) :
        LauAbsPdf(theVarName, params, limits.front(), limits.back()),
        normBin_(normalisationBin),
        limits_(limits)
{
        // Constructor for the PSF PDF.
        //
        // The parameters in params are the bin contents of all but the
        // normalisation bin, so has N_bins-1 entries.
        // The last argument specifies the limits of the bins and the range
        // as a whole, so has N_bins+1 entries.

        if (this->nParameters() != this->nBins()-1) {
                cerr<<"ERROR in LauParametricStepFuncPdf constructor: LauParametricStepFuncPdf requires N-1 parameters, where N is the number of bins."<<endl;
                gSystem->Exit(EXIT_FAILURE);
        }

        // Cache the normalisation factor
        this->calcNorm();
}

LauParametricStepFuncPdf::~LauParametricStepFuncPdf() 
{
        // Destructor
}

void LauParametricStepFuncPdf::calcLikelihoodInfo(const LauAbscissas& abscissas)
{
        // Check that the given abscissa is within the allowed range
        if (!this->checkRange(abscissas)) {
                gSystem->Exit(EXIT_FAILURE);
        }

        // Get our abscissa
        Double_t abscissa = abscissas[0];

        // Get the parameters
        const vector<LauAbsRValue*>& pars = this->getParameters();

        // Calculate value
        Double_t value(0.0);
        const UInt_t numBins = this->nBins();

        if ( this->normBin() == Last ) {
                // the last bin is our normalisation bin
                for ( UInt_t i(1); i<=numBins; ++i ) {
                        if ( abscissa < limits_[i] ) {
                                // in bin i-1 (starting with bin 0)
                                if ( i < numBins ) {
                                        // not in last bin
                                        value = pars[i-1]->unblindValue();
                                        break;
                                } else {
                                        // in last bin
                                        Double_t sum(0.0);
                                        Double_t binSize(0.0);
                                        for ( UInt_t j(1); j<numBins; ++j ) {
                                                binSize = limits_[j] - limits_[j-1];
                                                sum += ( pars[j-1]->unblindValue() * binSize );
                                        }
                                        binSize = limits_[numBins] - limits_[numBins-1];
                                        value = ( 1.0 - sum ) / binSize;
                                        break;
                                }
                        }
                }
        } else {
                // the first bin is our normalisation bin
                for ( UInt_t i(1); i<=numBins; ++i ) {
                        if ( abscissa < limits_[i] ) {
                                // in bin i-1 (starting with bin 0)
                                if ( i > 1 ) {
                                        // not in first bin
                                        value = pars[i-2]->unblindValue();
                                        break;
                                } else {
                                        // in first bin
                                        Double_t sum(0.0);
                                        Double_t binSize(0.0);
                                        for ( UInt_t j(2); j<=numBins; ++j ) {
                                                binSize = limits_[j] - limits_[j-1];
                                                sum += ( pars[j-2]->unblindValue() * binSize );
                                        }
                                        binSize = limits_[1] - limits_[0];
                                        value = ( 1.0 - sum ) / binSize;
                                        break;
                                }
                        }
                }
        }

        this->setUnNormPDFVal(value);

        // if the parameters are floating then we
        // need to recalculate the normalisation
        if (!this->cachePDF() && !this->withinNormCalc() && !this->withinGeneration()) {
                this->calcNorm();
        }
}

void LauParametricStepFuncPdf::calcNorm() 
{
        this->setNorm(1.0);
}

void LauParametricStepFuncPdf::calcPDFHeight( const LauKinematics* /*kinematics*/ )
{
        if (this->heightUpToDate()) {
                return;
        }

        // Get the parameters
        const vector<LauAbsRValue*>& pars = this->getParameters();

        // Find the PDF height
        Double_t height(0.0);
        Double_t value(0.0);
        const UInt_t numBins = this->nBins();

        if ( this->normBin() == Last ) {
                // the last bin is our normalisation bin

                // Check through all the parameterised bins
                for ( UInt_t i(0); i<numBins-1; ++i ) {
                        value = pars[i]->unblindValue();
                        if ( height < value ) {
                                height = value;
                        }
                }

                // Check the last bin
                Double_t sum(0.0);
                Double_t binSize(0.0);
                for ( UInt_t j(1); j<numBins; ++j ) {
                        binSize = limits_[j] - limits_[j-1];
                        sum += ( pars[j-1]->unblindValue() * binSize );
                }
                binSize = limits_[numBins] - limits_[numBins-1];
                value = ( 1.0 - sum ) / binSize;
                if ( height < value ) {
                        height = value;
                }
        } else {
                // the first bin is our normalisation bin

                // Check through all the parameterised bins
                for ( UInt_t i(1); i<numBins; ++i ) {
                        value = pars[i-1]->unblindValue();
                        if ( height < value ) {
                                height = value;
                        }
                }

                // Check the first bin
                Double_t sum(0.0);
                Double_t binSize(0.0);
                for ( UInt_t j(2); j<=numBins; ++j ) {
                        binSize = limits_[j] - limits_[j-1];
                        sum += ( pars[j-2]->unblindValue() * binSize );
                }
                binSize = limits_[1] - limits_[0];
                value = ( 1.0 - sum ) / binSize;
                if ( height < value ) {
                        height = value;
                }
        }

        this->setMaxHeight(height);
}