I am running a program on 2 different machines. On one it works fine without issue. On the other it results in a segmentation
fault. Through debugging, I have figured out where the
fault occurs, but I can't figure out a logical reason for it to happen.
In one function I have the following code:
pass_particles(particle_grid, particle_properties, input_data, coll_eros_track, collision_number_part, world, grid_rank_lookup, grid_locations);
cout<<"done passing particles"<<endl;
The function pass_particles looks like:
void pass_particles(map<int,map<int,Particle> > & particle_grid, std::vector<Particle_props> & particle_properties, User_input& input_data, data_tracking & coll_eros_track, vector<int> & collision_number_part, mpi::communicator & world, std::map<int,int> & grid_rank_lookup, map<int,std::vector<double> > & grid_locations)
{
//cout<<"east-west"<<endl;
//east-west exchange (x direction)
map<int, vector<Particle> > particles_to_be_sent_east;
map<int, vector<Particle> > particles_to_be_sent_west;
vector<Particle> particles_received_east;
vector<Particle> particles_received_west;
int counter_x_sent=0;
int counter_x_received=0;
for(grid_iter=particle_grid.begin();grid_iter!=particle_grid.end();grid_iter++)
{
map<int,Particle>::iterator part_iter;
for (part_iter=grid_iter->second.begin();part_iter!=grid_iter->second.end();)
{
if (particle_properties[part_iter->second.global_part_num()].particle_in_box()[grid_iter->first])
{
//decide if a particle has left the box...need to consider whether particle was already outside the box
if ((part_iter->second.position().x()<(grid_locations[grid_iter->first][0]) && part_iter->second.position().x()>(grid_locations[grid_iter->first-input_data.z_numboxes()][0]))
|| (input_data.periodic_walls_x() && (grid_iter->first-floor(grid_iter->first/(input_data.xz_numboxes()))*input_data.xz_numboxes()<input_data.z_numboxes()) && (part_iter->second.position().x()>(grid_locations[input_data.total_boxes()-1][0]))))
{
particles_to_be_sent_west[grid_iter->first].push_back(part_iter->second);
particle_properties[particle_grid[grid_iter->first][part_iter->first].global_part_num()].particle_in_box()[grid_iter->first]=false;
counter_sent++;
counter_x_sent++;
}
else if ((part_iter->second.position().x()>(grid_locations[grid_iter->first][1]) && part_iter->second.position().x()<(grid_locations[grid_iter->first+input_data.z_numboxes()][1]))
|| (input_data.periodic_walls_x() && (grid_iter->first-floor(grid_iter->first/(input_data.xz_numboxes()))*input_data.xz_numboxes())>input_data.xz_numboxes()-input_data.z_numboxes()-1) && (part_iter->second.position().x()<(grid_locations[0][1])))
{
particles_to_be_sent_east[grid_iter->first].push_back(part_iter->second);
particle_properties[particle_grid[grid_iter->first][part_iter->first].global_part_num()].particle_in_box()[grid_iter->first]=false;
counter_sent++;
counter_x_sent++;
}
//select particles in overlap areas to send to neighboring cells
else if ((part_iter->second.position().x()>(grid_locations[grid_iter->first][0]) && part_iter->second.position().x()<(grid_locations[grid_iter->first][0]+input_data.diam_large())))
{
particles_to_be_sent_west[grid_iter->first].push_back(part_iter->second);
counter_sent++;
counter_x_sent++;
}
else if ((part_iter->second.position().x()<(grid_locations[grid_iter->first][1]) && part_iter->second.position().x()>(grid_locations[grid_iter->first][1]-input_data.diam_large())))
{
particles_to_be_sent_east[grid_iter->first].push_back(part_iter->second);
counter_sent++;
counter_x_sent++;
}
++part_iter;
}
else if (particles_received_current[grid_iter->first].find(part_iter->first)!=particles_received_current[grid_iter->first].end())
{
if ((part_iter->second.position().x()>(grid_locations[grid_iter->first][0]) && part_iter->second.position().x()<(grid_locations[grid_iter->first][0]+input_data.diam_large())))
{
particles_to_be_sent_west[grid_iter->first].push_back(part_iter->second);
counter_sent++;
counter_x_sent++;
}
else if ((part_iter->second.position().x()<(grid_locations[grid_iter->first][1]) && part_iter->second.position().x()>(grid_locations[grid_iter->first][1]-input_data.diam_large())))
{
particles_to_be_sent_east[grid_iter->first].push_back(part_iter->second);
counter_sent++;
counter_x_sent++;
}
part_iter++;
}
else
{
particle_grid[grid_iter->first].erase(part_iter++);
counter_removed++;
}
}
}
world.barrier();
mpi::request reqs_x_send[particles_to_be_sent_west.size()+particles_to_be_sent_east.size()];
vector<multimap<int,int> > box_sent_x_info;
box_sent_x_info.resize(world.size());
vector<multimap<int,int> > box_received_x_info;
box_received_x_info.resize(world.size());
int counter_x_reqs=0;
//send particles
for(grid_iter_vec=particles_to_be_sent_west.begin();grid_iter_vec!=particles_to_be_sent_west.end();grid_iter_vec++)
{
if (grid_iter_vec->second.size()!=0)
{
//send a particle. 50 will be "west" tag
if (input_data.periodic_walls_x() && (grid_iter_vec->first-floor(grid_iter_vec->first/(input_data.xz_numboxes()))*input_data.xz_numboxes()<input_data.z_numboxes()))
{
reqs_x_send[counter_x_reqs++]=world.isend(grid_rank_lookup[grid_iter_vec->first + input_data.z_numboxes()*(input_data.x_numboxes()-1)], grid_iter_vec->first + input_data.z_numboxes()*(input_data.x_numboxes()-1), particles_to_be_sent_west[grid_iter_vec->first]);
box_sent_x_info[grid_rank_lookup[grid_iter_vec->first + input_data.z_numboxes()*(input_data.x_numboxes()-1)]].insert(pair<int,int>(world.rank(), grid_iter_vec->first + input_data.z_numboxes()*(input_data.x_numboxes()-1)));
}
else if (!(grid_iter_vec->first-floor(grid_iter_vec->first/(input_data.xz_numboxes()))*input_data.xz_numboxes()<input_data.z_numboxes()))
{
reqs_x_send[counter_x_reqs++]=world.isend(grid_rank_lookup[grid_iter_vec->first - input_data.z_numboxes()], grid_iter_vec->first - input_data.z_numboxes(), particles_to_be_sent_west[grid_iter_vec->first]);
box_sent_x_info[grid_rank_lookup[grid_iter_vec->first - input_data.z_numboxes()]].insert(pair<int,int>(world.rank(),grid_iter_vec->first - input_data.z_numboxes()));
}
}
}
for(grid_iter_vec=particles_to_be_sent_east.begin();grid_iter_vec!=particles_to_be_sent_east.end();grid_iter_vec++)
{
if (grid_iter_vec->second.size()!=0)
{
//send a particle. 60 will be "east" tag
if (input_data.periodic_walls_x() && (grid_iter_vec->first-floor(grid_iter_vec->first/(input_data.xz_numboxes())*input_data.xz_numboxes())>input_data.xz_numboxes()-input_data.z_numboxes()-1))
{
reqs_x_send[counter_x_reqs++]=world.isend(grid_rank_lookup[grid_iter_vec->first - input_data.z_numboxes()*(input_data.x_numboxes()-1)], 2000000000-(grid_iter_vec->first - input_data.z_numboxes()*(input_data.x_numboxes()-1)), particles_to_be_sent_east[grid_iter_vec->first]);
box_sent_x_info[grid_rank_lookup[grid_iter_vec->first - input_data.z_numboxes()*(input_data.x_numboxes()-1)]].insert(pair<int,int>(world.rank(),2000000000-(grid_iter_vec->first - input_data.z_numboxes()*(input_data.x_numboxes()-1))));
}
else if (!(grid_iter_vec->first-floor(grid_iter_vec->first/(input_data.xz_numboxes())*input_data.xz_numboxes())>input_data.xz_numboxes()-input_data.z_numboxes()-1))
{
reqs_x_send[counter_x_reqs++]=world.isend(grid_rank_lookup[grid_iter_vec->first + input_data.z_numboxes()], 2000000000-(grid_iter_vec->first + input_data.z_numboxes()), particles_to_be_sent_east[grid_iter_vec->first]);
box_sent_x_info[grid_rank_lookup[grid_iter_vec->first + input_data.z_numboxes()]].insert(pair<int,int>(world.rank(), 2000000000-(grid_iter_vec->first + input_data.z_numboxes())));
}
}
}
counter=0;
for (int i=0;i<world.size();i++)
{
//if (world.rank()!=i)
//{
reqs[counter++]=world.isend(i,1000000000,box_sent_x_info[i]);
reqs[counter++]=world.irecv(i,1000000000,box_received_x_info[i]);
//}
}
mpi::wait_all(reqs, reqs + world.size()*2);
//receive particles
//receive west particles
for (int j=0;j<world.size();j++)
{
multimap<int,int>::iterator received_info_iter;
for (received_info_iter=box_received_x_info[j].begin();received_info_iter!=box_received_x_info[j].end();received_info_iter++)
{
//receive the message
if (received_info_iter->second<1000000000)
{
//receive the message
world.recv(received_info_iter->first,received_info_iter->second,particles_received_west);
//loop through all the received particles and add them to the particle_grid for this processor
for (unsigned int i=0;i<particles_received_west.size();i++)
{
particle_grid[received_info_iter->second].insert(pair<int,Particle>(particles_received_west[i].global_part_num(),particles_received_west[i]));
if(particles_received_west[i].position().x()>grid_locations[received_info_iter->second][0] && particles_received_west[i].position().x()<grid_locations[received_info_iter->second][1])
{
particle_properties[particles_received_west[i].global_part_num()].particle_in_box()[received_info_iter->second]=true;
}
counter_received++;
counter_x_received++;
}
}
else
{
//receive the message
world.recv(received_info_iter->first,received_info_iter->second,particles_received_east);
//loop through all the received particles and add them to the particle_grid for this processor
for (unsigned int i=0;i<particles_received_east.size();i++)
{
particle_grid[2000000000-received_info_iter->second].insert(pair<int,Particle>(particles_received_east[i].global_part_num(),particles_received_east[i]));
if(particles_received_east[i].position().x()>grid_locations[2000000000-received_info_iter->second][0] && particles_received_east[i].position().x()<grid_locations[2000000000-received_info_iter->second][1])
{
particle_properties[particles_received_east[i].global_part_num()].particle_in_box()[2000000000-received_info_iter->second]=true;
}
counter_received++;
counter_x_received++;
}
}
}
}
mpi::wait_all(reqs_y_send, reqs_y_send + particles_to_be_sent_bottom.size()+particles_to_be_sent_top.size());
mpi::wait_all(reqs_z_send, reqs_z_send + particles_to_be_sent_south.size()+particles_to_be_sent_north.size());
mpi::wait_all(reqs_x_send, reqs_x_send + particles_to_be_sent_west.size()+particles_to_be_sent_east.size());
cout<<"x sent "<<counter_x_sent<<" and received "<<counter_x_received<<" from rank "<<world.rank()<<endl;
cout<<"rank "<<world.rank()<<" sent "<<counter_sent<<" and received "<<counter_received<<" and removed "<<counter_removed<<endl;
cout<<"done passing"<<endl;
}
I only posted some of the code (so ignore the fact that some variables may appear to be undefined, as they are in a portion of the code I didn't post)
When I run the code (on the machine in which it fails), I get done passing but not done passing particles
I am lost as to what could possibly cause a segmentation
fault between the end of the called function and the next line in the calling function and why it would happen on one machine and not another.
