Osama Gazali
Sep 22, 2014, 6:08:24 AM9/22/14
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Concerning scratch file, I want to output the statistic of Packet InterReceptionTime of nested map. first map is consist of a key (receptionID) and irtMap and the second one hole SourceID and receptiontime (rxTime).
I got segmentation fault in the second for loop and exactly in the line below
for (std::map<uint64_t, std::vector<uint64_t>*>::iterator j=irtMap->begin(); j!=irtMap->end(); ++j)
I used gdb which help to pinpoint the problem but i could not find where is the problem. Could you help please?
void ComputeStatistics()
{
std::vector<uint64_t>::iterator vi;
//int k =0;
int k;
uint64_t tmp_RxTime;
uint64_t sum_RxTime = 0;
//file_log2<<" RX_ID "<<" "<<" TX_ID "<<" "<<" average IRT "<<" "<<" variance IRT "<<" "<<" std_dev IRT "<<" "<<std::endl;
std::cout<<" CALLED33 Trace "<<std::endl;
if (globalIrtMap == NULL) {
return;
std::cout<<" CALLED44 Trace "<<std::endl;
}
for (std::map<uint64_t, std::map<uint64_t, std::vector<uint64_t>*>*>::iterator i=globalIrtMap->begin(); i!=globalIrtMap->end(); ++i)
{
std::cout<<" CALLED55 Trace "<<std::endl;
std::cout <<" rxId "<< i->first << " IrtMap " << i->second <<endl;
std::map<uint64_t, std::vector<uint64_t>*>* irtMap = (*i).second;
std::cout<<" CALLED66 Trace "<<std::endl;
if (irtMap == NULL) { // we should never enter here but just in case
std::cout<<" CALLED77 Trace "<<std::endl;
continue;
}
for (std::map<uint64_t, std::vector<uint64_t>*>::iterator j=irtMap->begin(); j!=irtMap->end(); ++j)
{
std::cout<<" CALLED88 Trace "<<std::endl;
std::vector<uint64_t>* rxTime = (*j).second;
//if (rxTime == NULL) { // we should never enter here but just in case
// std::cout<<" CALLED99 Trace "<<std::endl;
// continue;
//}
for (vi = rxTime->begin()+1; vi<rxTime->end(); ++vi)
{
std::cout<<" CALLED1010 Trace "<<std::endl;
tmp_RxTime = *vi - *(vi-1);
rxTime->insert(vi-1, tmp_RxTime);
//I want to keep this in a vector to use it for variance calculation
std::cout<<"Inter-ReceptionTime to calculate the variance"<<tmp_RxTime<<std::endl;
sum_RxTime += tmp_RxTime;
}
//*1* To compute the average irt*****************************************************************************
uint64_t av_RxTime = sum_RxTime/(rxTime->size()-1);
std::cout<<" Average_Inter-ReceptionTime for each dedicated bi-directional communication "<<av_RxTime<<std::endl;
//*2* To compute the variance of irt**************************************************************************
uint64_t sample_variance = 0;
for (k = 1; k < rxTime->size()-1 ; ++k)
{
//variance[k-1]= rxTime->at(k) - rxTime->at(k-1);
sample_variance += ( ((rxTime->at(k) - rxTime->at(k-1)) - av_RxTime)*((rxTime->at(k) - rxTime->at(k-1)) - av_RxTime) / rxTime->size()-2) ;
std::cout<<" CALLED1111 Trace "<<std::endl;
}
//*3* To compute the variance of irt**************************************************************************
uint64_t stdDeviation = sqrt (sample_variance);
std::cout<<" standard deviation of the inter-reception time of packets"<<stdDeviation<<std::endl;
//*4* To plot the statistics of irt**************************************************************************
file_log2<<" RX_ID "<<(*i).first<<" TX_ID "<<(*j).first<<" average IRT "<<av_RxTime<<" variance IRT "<<sample_variance<<" std_dev IRT "<<stdDeviation<<std::endl;
}
std::cout<<" CALLED1212 Trace "<<std::endl;
}
std::cout<<" CALLED1313 Trace "<<std::endl;
}
void ActivateCamTxon(PacketManager* packetManager, uint32_t nodeId)
{
TechnologyList techList;
techList.push_back("WaveVehicle");
//this is the frequency of CAM correspond to maximum allowable CAM could be transmit per second from DCC prespective
packetManager->ActivateCamTxon(nodeId, 10.0, 400);
}
Konstantinos
Sep 22, 2014, 6:32:53 AM9/22/14
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Hi,
With only this information we can not help you.
What was the error/backtrace you got from gdb?
Check the individual variables such as irtMap to identify how many entries it has.
It might have only one entry and by using pre-increment in the loop (http://stackoverflow.com/a/484492), you are getting the segfault.
How many times do you get in the loop? E.g. print the size of the map before you enter the loop and then check the loops you actually do.
Osama Gazali
Sep 22, 2014, 11:33:32 AM9/22/14
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This is the backtrace and the first two stack frame does not give me any meaning. stack frame number 2 is the problem
the segFault occur in a line where there is no execution. it is a bit confusing for me.Breakpoint 1, ComputeStatistics () at ../scratch/den.cc:95
95 std::vector<uint64_t>::iterator vi;
(gdb) next
99 uint64_t sum_RxTime = 0;
(gdb)
103 std::cout<<" CALLED33 Trace "<<std::endl;
(gdb)
CALLED33 Trace
105 if (globalIrtMap == NULL) {
(gdb)
111 for (std::map<uint64_t, std::map<uint64_t, std::vector<uint64_t>*>*>::iterator i=globalIrtMap->begin(); i!=globalIrtMap->end(); ++i)
(gdb)
113 std::cout<<" CALLED55 Trace "<<std::endl;
(gdb)
CALLED55 Trace
115 std::map<uint64_t, std::vector<uint64_t>*>* irtMap = (*i).second;
(gdb)
117 std::cout <<" rxId "<< (*i).first << " IrtMap " << (*i).second <<endl;
(gdb)
rxId 15642270892032 IrtMap 0x11d700000000
118 //std::cout << "irtMap.size() is " << irtMap->size() <<endl;
(gdb)
Program received signal SIGSEGV, Segmentation fault.
0x000000000042a698 in std::_Rb_tree<unsigned long, std::pair<unsigned long const, std::vector<unsigned long, std::allocator<unsigned long> >*>, std::_Select1st<std::pair<unsigned long const, std::vector<unsigned long, std::allocator<unsigned long> >*> >, std::less<unsigned long>, std::allocator<std::pair<unsigned long const, std::vector<unsigned long, std::allocator<unsigned long> >*> > >::size (this=0x11d700000000)
at /usr/include/c++/4.8/bits/stl_tree.h:728
728 { return _M_impl._M_node_count; }
(gdb) backtrace
#0 0x000000000042a698 in std::_Rb_tree<unsigned long, std::pair<unsigned long const, std::vector<unsigned long, std::allocator<unsigned long> >*>, std::_Select1st<std::pair<unsigned long const, std::vector<unsigned long, std::allocator<unsigned long> >*> >, std::less<unsigned long>, std::allocator<std::pair<unsigned long const, std::vector<unsigned long, std::allocator<unsigned long> >*> > >::size (
this=0x11d700000000) at /usr/include/c++/4.8/bits/stl_tree.h:728
#1 0x0000000000428c24 in std::map<unsigned long, std::vector<unsigned long, std::allocator<unsigned long> >*, std::less<unsigned long>, std::allocator<std::pair<unsigned long const, std::vector<unsigned long, std::allocator<unsigned long> >*> > >::size (this=0x11d700000000)
at /usr/include/c++/4.8/bits/stl_map.h:435
#2 0x000000000040db46 in ComputeStatistics () at ../scratch/den.cc:118
#3 0x0000000000423b3b in main (argc=1, argv=0x7fffffffe2c8) at ../scratch/den.cc:2180
(gdb) up
#1 0x0000000000428c24 in std::map<unsigned long, std::vector<unsigned long, std::allocator<unsigned long> >*, std::less<unsigned long>, std::allocator<std::pair<unsigned long const, std::vector<unsigned long, std::allocator<unsigned long> >*> > >::size (this=0x11d700000000)
at /usr/include/c++/4.8/bits/stl_map.h:435
435 { return _M_t.size(); }
(gdb) up
#2 0x000000000040db46 in ComputeStatistics () at ../scratch/den.cc:118
118 //std::cout << "irtMap.size() is " << irtMap->size() <<endl;
(gdb)
One thing i want to reply concerning how to print the size of the map and identify how many entries it has.
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