Large-Scale Agent-based Modeling with Repast HPC: A Case Study in Parallelizing an Agent-based Model, supplementary materials (PADABS 2015 Workshop Paper)

Loops_OMP.cpp

NextAct next_act;
size_t n = persons.size();
#pragma omp parallel for firstprivate(next_act)
for (size_t i = 0; i < n; ++i) {
	auto& person = persons[i];
	person->selectNextAct(cal, next_act);
	#pragma omp critical
	{
		next_act.place->addPerson(person);
	}
}

n = places.size();
#pragma omp parallel for
for (size_t i = 0; i < n; ++i) {
	places[i]->clear();
}

PersonCachingExample.cpp

// *data variable contains all person data to a process as an array of ints
// total_amt_received variable is the total number of persons received by the receiving process
// remote_persons map is the cache of all received persons
// local_persons map is the map of currently active persons on the process. We iterate through this map
// when iterating through the person loop
for (int i = 0; i < total_amt_received; i += PERSON_SEND_DATA_SIZE) {
	int next_place_id = data[i];
	int act_type = data[i + 1];
	int p_id = data[i + 2];
	
	// look up person in the "remote_persons" cache using the sent person id
	auto iter = remote_persons.find(p_id);
	if (iter == remote_persons.end()) {
		// the person is not found so construct person from activity etc. caches
		std::shared_ptr<Activities> weekday = acts_cache[data[i + 4]];
		...
		// make the person from the cached data, and the current disease state
		shared_ptr<Person> p = make_shared<Person>("remote", p_id, p_places, weekday, weekend);
		p->setDiseaseState(state);
		// insert the person into the "remote_persons" cache
		remote_persons.insert(make_pair(p_id, p));
		// add person to local_persons map
		local_persons.insert(make_pair(p_id, p));
	} else {
		// person is found in the cache so just update the disease state
		iter->second->setDiseaseState(state);
		// add person to local_persons map. 
		local_persons.insert((*iter));
	}
}

TAUProfiling.cpp

// define a timer "t1" that can be used to profile a section of code,
// in this case the person loop
TAU_PROFILE_TIMER(t1,"person-select-place", "void (void)", TAU_USER);
// start the timer
TAU_PROFILE_START(t1);
for (auto p_iter = local_persons.begin(); p_iter != local_persons.end();) {
	auto& person = p_iter->second;
	person->selectNextAct(cal, next_act);

	if (rank_ != next_act.place_rank()) {
		...
	} else {
		...
	}
}
// stop the timer
TAU_PROFILE_STOP(t1);