TFCSPCAEnergyParametrization.cxx File Reference

#include "CLHEP/Random/RandGaussZiggurat.h"
#include "CLHEP/Random/RandFlat.h"
#include "ISF_FastCaloSimEvent/TFCSPCAEnergyParametrization.h"
#include "ISF_FastCaloSimEvent/FastCaloSim_CaloCell_ID.h"
#include "ISF_FastCaloSimEvent/TFCSSimulationState.h"
#include "ISF_FastCaloSimEvent/TFCSExtrapolationState.h"
#include "TFile.h"
#include "TKey.h"
#include "TClass.h"
#include "TMatrixD.h"
#include "TMatrixDSymEigen.h"
#include "TMath.h"
#include "TH1.h"
#include "CxxUtils/restrict.h"

Go to the source code of this file.

Functions
float	interpolate_get_y (TH1 *hist, float x)

Function Documentation

interpolate_get_y()

float interpolate_get_y	(	TH1 *	hist,
		float	x
	)

Definition at line 68 of file TFCSPCAEnergyParametrization.cxx.

                                            {
  float m = 0;
  float n = 0;
  float x1 = 1;
  float x2 = 0;
  float y1 = 0;
  float y2 = 0;
  if (x <= hist->GetBinCenter(1))
    return hist->GetBinContent(1);
  if (x >= hist->GetBinCenter(hist->GetNbinsX()))
    return hist->GetBinContent(hist->GetNbinsX());
 
  int bin = hist->FindBin(x);
  // is x above the bin center -> interpolate with next bin
  if (x > hist->GetBinCenter(bin)) {
    x1 = hist->GetBinCenter(bin);
    y1 = hist->GetBinContent(bin);
    x2 = hist->GetBinCenter(bin + 1);
    y2 = hist->GetBinContent(bin + 1);
  }
 
  // is x below bin center -> interpolate with previous bin
  if (x <= hist->GetBinCenter(bin)) {
    x1 = hist->GetBinCenter(bin - 1);
    y1 = hist->GetBinContent(bin - 1);
    x2 = hist->GetBinCenter(bin);
    y2 = hist->GetBinContent(bin);
  }
 
  m = (y1 - y2) / (x1 - x2);
  n = y2 - m * x2;
  return m * x + n;
}