From: hristov <hristov@f7af4fe6-9843-0410-8265-dc069ae4e863>
Date: Wed, 31 Jan 2007 17:02:56 +0000 (+0000)
Subject: Fix to take into account the fact that Pythia6 from ROOT
X-Git-Url: http://git.uio.no/git/?p=u%2Fmrichter%2FAliRoot.git;a=commitdiff_plain;h=562cbbcf710dcf598f565a35c6d563d4e40a5d08;ds=sidebyside

Fix to take into account the fact that Pythia6 from ROOT
stores the original PYTHIA mother/indices which is done the FORTRAN way
(1, 2, 3 ...). In AliStack we use the C++ counting (0, 1, 2, ..)

Andreas
---

diff --git a/PYTHIA6/AliGenPythia.cxx b/PYTHIA6/AliGenPythia.cxx
index 9ad2f82d53f..daaa22261a4 100644
--- a/PYTHIA6/AliGenPythia.cxx
+++ b/PYTHIA6/AliGenPythia.cxx
@@ -840,7 +840,7 @@ Int_t  AliGenPythia::GenerateMB()
 	TParticle* iparticle = (TParticle *) fParticles->At(i);
 	if(iparticle->GetStatusCode()==1 && iparticle->GetPdgCode()==pdg && 
 	   iparticle->Pt() > fFragPhotonOrPi0MinPt){
-	  Int_t imother = iparticle->GetFirstMother();
+	  Int_t imother = iparticle->GetFirstMother() - 1;
 	  TParticle* pmother = (TParticle *) fParticles->At(imother);
 	  if(pdg == 111 || 
 	     (pdg == 22 && pmother->GetStatusCode() != 11))//No photon from hadron decay