TVector2 mQ;
float mQx=0, mQy=0;
- AliFemtoParticle* flowparticle;
- AliFemtoParticleIterator pIter;
- AliFemtoParticleIterator startLoop = particlecollection->begin();
- AliFemtoParticleIterator endLoop = particlecollection->end();
- for (pIter=startLoop;pIter!=endLoop;pIter++){
- flowparticle = *pIter;
- mQx += (cos(2*flowparticle->FourMomentum().Phi()))*(flowparticle->Track()->Pt());
- mQy += (sin(2*flowparticle->FourMomentum().Phi()))*(flowparticle->Track()->Pt());
- }
+ if (!particlecollection) {
+ mQ.Set(0.0, 0.0);
+ return mQ;
+ }
+ AliFemtoParticle* flowparticle;
+ AliFemtoParticleIterator pIter;
+ AliFemtoParticleIterator startLoop = particlecollection->begin();
+ AliFemtoParticleIterator endLoop = particlecollection->end();
+ for (pIter=startLoop;pIter!=endLoop;pIter++){
+ flowparticle = *pIter;
+ mQx += (cos(2*flowparticle->FourMomentum().Phi()))*(flowparticle->Track()->Pt());
+ mQy += (sin(2*flowparticle->FourMomentum().Phi()))*(flowparticle->Track()->Pt());
+ }
+
mQ.Set(mQx,mQy);
return mQ;
}