Equivalent of HepPoint3D

ROOT
1

Hello,

If I want the equivalanet of a Hep3Vector I can use TVector3 in root. However I would like the equivalent of HePoint3D. Is there such an equivalent in root? (I cant find it using the reference classes webpage)

Thanks,

Mark

2

Hello Mark,

if you are using ROOT version 5, the equivalent of the HepPoint3D is the class PositionVector3D in mathcore. Reference documentation for the mathcore classes is available at
seal.web.cern.ch/seal/MathLibs/M … _0_4/html/

Please let me know if you have further questions,

Cheers

Lorenzo

3

[quote=“moneta”]Hello Mark,

if you are using ROOT version 5, the equivalent of the HepPoint3D is the class PositionVector3D in mathcore. Reference documentation for the mathcore classes is available at
seal.web.cern.ch/seal/MathLibs/M … _0_4/html/

Please let me know if you have further questions,

Cheers

Lorenzo[/quote]

I tried to use it but I dont understand how. I put in my code:

ROOT::Math::PositionVector3D showerCenter(xc,yc,zc);

where xc,yc and zc are Double_t. The compiler says:

[hodgkinson@hep1 EFlowAnalysis]$ gmake
Compiling EFlowCompiledMacros.cc
In file included from EFlowCompiledMacros.cc:92:
/home/hodgkinson/EFlowAnalysis/macros/TrackPid_reCalcMoments.C: In function
void TrackPid_reCalcMoments()': /home/hodgkinson/EFlowAnalysis/macros/TrackPid_reCalcMoments.C:91: invalid use of templatetemplate class ROOT::Math::PositionVector3D’
/home/hodgkinson/EFlowAnalysis/macros/TrackPid_reCalcMoments.C:91: syntax error
before `(’ token

in the link you sent I see CoordSystem is a template and scalar is defined as CoordSystem::Scalar. I still dont understand what a scalar is or how to use Positionvector3D.

What is the equivalent of saying HepPoint3D myPoint(3,4,5)?

Thanks,

Mark

4

Hi Mark,

The class PositionVector3D is template on the Coordinate system.
You can choose the coordinate system on which to base the Vector, like Cartesian or Polar.
I you want to use the Cartesian I would recommend you to use the
typdef XYZPoint which is a PositionVector3D<Cartesian3D >.

do:

#include “Math/Point3D.h”

ROOT::Math::XYZPoint( xc, yc, zc);

5

you find also examples how to use it (for Points) in

seal.web.cern.ch/seal/MathLibs/M … DPage.html

hope this help,

Cheers,

Lorenzo