PolygonBase.cxx

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/*
  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
*/
 
#include <iostream>
#include <cstdlib>
#include "MuonCalibMath/PolygonBase.h"
#include "GeoModelKernel/throwExcept.h"
using namespace MuonCalib;
 
PolygonBase::PolygonBase(const std::vector<double> & x) {
 
    // CHECK FOR CORRECT FILLING
    for (unsigned int k=0; k<x.size()-1; k++) {
        if (x[k]>=x[k+1]) {
            THROW_EXCEPTION("PolygonBase::init - Abscissae not in increasing order!");
        }
    }
    // TRANSFER THE INPUT DATA //
    m_x = x;
}
double PolygonBase::value(const int  k, const double  x) const {
 
    // CHECK THE BASE FUNCTION INDEX //
    if (k<0 || k>static_cast<int>(m_x.size()-1)) {
        THROW_EXCEPTION("PolygonBase::value - Illegal function index "<<k<<"! Should be >0 and "<<m_x.size());
    }
 
    // outside the domain of the polygon //
    if (x<m_x[0] || x>m_x[m_x.size()-1]) {
        return 0.0;
    }
    // inside the domain of the polygon //
    if (k==0 && x<m_x[0]) {
        return 0.0;
    }
    if (k==0 && x<=m_x[1]) {
        return (m_x[1]-x)/(m_x[1]-m_x[0]);
    }
    if (k==0 && x>m_x[1]) {
        return 0.0;
    }
    if (static_cast<unsigned int>(k)==m_x.size()-1 &&
                            x<=m_x[m_x.size()-2]) {
        return 0.0;
    }
    if (static_cast<unsigned int>(k)==m_x.size()-1 &&
                            x<=m_x[m_x.size()-1]) {
        return (x-m_x[k-1])/(m_x[k]-m_x[k-1]);
    }
    if (static_cast<unsigned int>(k)==m_x.size()-1 &&
                            x>m_x[m_x.size()-1]) {
        return 0.0;
    }
    if (x<m_x[k-1] || x>m_x[k+1]) {
        return 0.0;
    }
 
    if (x<m_x[k]) {
        return (x-m_x[k-1])/(m_x[k]-m_x[k-1]);
    }
    return (m_x[k+1]-x)/(m_x[k+1]-m_x[k]);
}