terminate called after throwing an instance of std::bad_alloc - c++

Question

I am facing the current error since last few days and fighting with it to resolve the problem but all in vain. I am using Pythia8 and fastjet event generator together and running my simple code. Code compiled nicely but causes run time error as shown below. It runs fine with low events but for large iterations(events) it failed and print the error under discussion:
PYTHIA Warning in SpaceShower::pT2nextQCD: weight above unity
PYTHIA Error in StringFragmentation::fragment: stuck in joining
PYTHIA Error in Pythia::next: hadronLevel failed; try again
PYTHIA Error in SpaceShower::pT2nearQCDthreshold: stuck in loop
PYTHIA Error in StringFragmentation::fragmentToJunction: caught in junction flavour loop
PYTHIA Warning in StringFragmentation::fragmentToJunction: bad convergence junction rest frame
PYTHIA Warning in MultipleInteractions::pTnext: weight above unity
terminate called after throwing an instance of 'std::bad_alloc'
what(): std::bad_alloc
here is code:
[
double Rparam = 0.4;
fastjet::Strategy strategy = fastjet::Best;
fastjet::RecombinationScheme recombScheme = fastjet::Et_scheme;
fastjet::JetDefinition *jetDef = NULL;
jetDef = new fastjet::JetDefinition(fastjet::antikt_algorithm, Rparam,
recombScheme, strategy);
// Fastjet input
std::vector <fastjet::PseudoJet> fjInputs;
//================== event selection efficiency variables ==========
int nev=0;
int passedJetCut=0;
int passedBJetCut=0;
int passedLeptonCut=0;
int passedMtaunuCut=0;
int passedMtaunubCut=0;
int passedWCut=0;
int passedTopCut=0;
int passedMetCut=0;
int njets=2;
int nbjets=1;
int ntaus=1;
double MW=80.38;
// Begin event loop. Generate event. Skip if error. List first one.
for (int iEvent = 0; iEvent < HowManyEvents; ++iEvent) {
nev++;
if(iEvent%1000==0)cout<<"Event number "<<iEvent<<endl;
// cout<<"Event number "<<iEvent<<endl;
//==================== PYTHIA ==================
if(!pythia.next())continue;
// if (iEvent<3)pythia.process.list();
if (iEvent<2)pythia.event.list();
//if (iEvent<2)event.list();
//==================== TAUOLA ==================
// Convert event record to HepMC
HepMC::GenEvent * HepMCEvt = new HepMC::GenEvent();
//Conversion needed if HepMC uses different momentum units
//than Pythia. However, requires HepMC 2.04 or higher.
HepMCEvt->use_units(HepMC::Units::GEV,HepMC::Units::MM);
ToHepMC.fill_next_event(pythia, HepMCEvt);
// if (FirstEvent)event.list();
//Beware this does not reflect tauola effect
//tauola C++ interface only affects HepMC::GenEvent which is made
// from pythia.event
//run TAUOLA on the event
TauolaHepMCEvent * t_event = new TauolaHepMCEvent(HepMCEvt);
//Since we let Pythia decay taus, we have to undecay them first.
t_event->undecayTaus();
t_event->decayTaus();
// Reset Fastjet input for each event
fjInputs.resize(0);
// Keep track of missing ET
//*******************
class IsbFromTop {
public:
bool operator()( const HepMC::GenParticle* p ) {
if ( abs(p->pdg_id()) == 5 ) return 1;
return 0;
}
};
vector<bjet> bjets;
bjets.clear();
//======================= loop over particles ========================
for(HepMC::GenEvent::particle_const_iterator p = HepMCEvt->particles_begin();
p!= HepMCEvt->particles_end(); ++p ){
int pid=(*p)->pdg_id();
double pt=(*p)->momentum().perp();
double px=(*p)->momentum().px();
double py=(*p)->momentum().py();
double pz=(*p)->momentum().pz();
double e=(*p)->momentum().e();
double eta=(*p)->momentum().eta();
double phi=(*p)->momentum().phi();
if(abs(pid)==15){
if ( (*p)->production_vertex() ) {
for ( HepMC::GenVertex::particle_iterator mother =
(*p)->production_vertex()->particles_begin(HepMC::parents);
mother!=(*p)->production_vertex()->particles_end(HepMC::parents);
++mother )
{
if(abs((*mother)->pdg_id())==24){
W2Tau=true;
}
}
}
}
// Final state only
if ((*p)->status()!=1)continue;
if(abs(pid)==11 || abs(pid)==13){
if(!FoundLepton){
hleptonet->Fill(pt);
hleptoneta->Fill(eta);
hleptonphi->Fill(phi);
pxlepton=px;
pylepton=py;
pzlepton=pz;
elepton=e;
FoundLepton=true;
}
if(pt>20. && pt<80. && fabs(eta)<1.5)
nleptons++;
}
// No neutrinos
if (abs(pid)==12 ||
abs(pid)==14 ||
abs(pid)==16){nnu++;continue;}
// Only |eta| < 5
if(fabs(eta)>5.)continue;
// Missing ET
mex -= px;
mey -= py;
// Store as input to Fastjhttps://mail.google.com/mail/u/0/?shva=1#inboxet
fjInputs.push_back(fastjet::PseudoJet (px,py,pz,e));
}//loop over particles in the event
continue.............................
thanks a lot for your help
ijaz

Answer 1

Sorry I don't know anything about Pythia but in c++ new Operator will return either allocated memory pointer or it will throw a bad_alloc exception.
Using try catch we can solve this issue-
Like:
while(true)
{
try
{
string s = new string(1024*1024*1024);
break;
}
catch
{
// do stuff
}
}
It will solve the crashing issue but the CPU utilization will go UP until we got the required memory.(and if CPU reach at 100% usage it will hang the system)