MathTools/src/MathUtils.cc

// $Id: MathUtils.cc,v 1.5 2009/02/18 15:38:26 loizides Exp $

#include "MitCommon/MathTools/interface/MathUtils.h"

using namespace mithep;

//--------------------------------------------------------------------------------------------------
Double_t MathUtils::AddInQuadrature(Double_t a, Double_t b)
{
  // Add quantities in quadrature.

  return(TMath::Sqrt(a*a + b*b));
}

//--------------------------------------------------------------------------------------------------
Double_t MathUtils::DeltaPhi(Double_t phi1, Double_t phi2)
{
  // Compute DeltaPhi between two given angles. Results is in [-pi/2,pi/2].

  Double_t dphi = TMath::Abs(phi1-phi2);
  while (dphi>TMath::Pi())
    dphi = TMath::Abs(dphi - TMath::TwoPi());
  return(dphi);
}

//--------------------------------------------------------------------------------------------------
Double_t MathUtils::DeltaR(Double_t phi1, Double_t eta1, Double_t phi2, Double_t eta2)
{
  // Compute DeltaR between two given points in the eta/phi plane.

  Double_t dphi = DeltaPhi(phi1, phi2);
  Double_t deta = eta1-eta2;
  Double_t dR = TMath::Sqrt(dphi*dphi + deta*deta);
  return(dR);
}

//--------------------------------------------------------------------------------------------------
Double_t MathUtils::Eta2Theta(Double_t eta) 
{ 
  // Compute theta from given eta value.

  return 2.*TMath::ATan(exp(-eta)); 
}

//--------------------------------------------------------------------------------------------------
Double_t MathUtils::Theta2Eta(Double_t theta) 
{ 
  // Compute eta from given theta value.

  return -TMath::Log(TMath::Tan(theta/2.)); 
}
Revision:	1.6
Committed:	Fri Mar 20 13:33:19 2009 UTC (16 years, 1 month ago) by loizides
Content type:	text/plain
Branch:	MAIN
CVS Tags:	Mit_009
Changes since 1.5:	+1 -33 lines
Log Message:	Cleanup
#	User	Rev	Content
1	loizides	1.6	// $Id: MathUtils.cc,v 1.5 2009/02/18 15:38:26 loizides Exp $
2	sixie	1.1
3			#include "MitCommon/MathTools/interface/MathUtils.h"
4
5	loizides	1.3	using namespace mithep;
6	sixie	1.1
7	loizides	1.2	//--------------------------------------------------------------------------------------------------
8	loizides	1.4	Double_t MathUtils::AddInQuadrature(Double_t a, Double_t b)
9	loizides	1.2	{
10	loizides	1.5	// Add quantities in quadrature.
11
12	loizides	1.2	return(TMath::Sqrt(aa + bb));
13			}
14	sixie	1.1
15	loizides	1.2	//--------------------------------------------------------------------------------------------------
16	loizides	1.4	Double_t MathUtils::DeltaPhi(Double_t phi1, Double_t phi2)
17	sixie	1.1	{
18	loizides	1.5	// Compute DeltaPhi between two given angles. Results is in [-pi/2,pi/2].
19
20	loizides	1.4	Double_t dphi = TMath::Abs(phi1-phi2);
21			while (dphi>TMath::Pi())
22			dphi = TMath::Abs(dphi - TMath::TwoPi());
23			return(dphi);
24	sixie	1.1	}
25
26	loizides	1.2	//--------------------------------------------------------------------------------------------------
27	loizides	1.4	Double_t MathUtils::DeltaR(Double_t phi1, Double_t eta1, Double_t phi2, Double_t eta2)
28			{
29	loizides	1.5	// Compute DeltaR between two given points in the eta/phi plane.
30
31	loizides	1.4	Double_t dphi = DeltaPhi(phi1, phi2);
32			Double_t deta = eta1-eta2;
33			Double_t dR = TMath::Sqrt(dphidphi + detadeta);
34	sixie	1.1	return(dR);
35			}
36
37	loizides	1.2	//--------------------------------------------------------------------------------------------------
38	loizides	1.4	Double_t MathUtils::Eta2Theta(Double_t eta)
39	loizides	1.2	{
40	loizides	1.5	// Compute theta from given eta value.
41
42	loizides	1.2	return 2.*TMath::ATan(exp(-eta));
43	sixie	1.1	}
44
45	loizides	1.2	//--------------------------------------------------------------------------------------------------
46	loizides	1.4	Double_t MathUtils::Theta2Eta(Double_t theta)
47	loizides	1.2	{
48	loizides	1.5	// Compute eta from given theta value.
49
50	loizides	1.2	return -TMath::Log(TMath::Tan(theta/2.));
51	sixie	1.1	}