Method MigrateOrganism

avida-core/source/main/cMultiProcessWorld.cc:142–193

! Migrate this organism to a different world. If this method is called, it means that this organism is to be migrated to a *different* world (ie, it shouldn't be migrated back to this world). Conditions that depend on geometry of the worlds are checked over in IsWorldBoundary(). */

 Conditions that depend on geometry of the worlds are checked over in IsWorldBoundary().
 */
void cMultiProcessWorld::MigrateOrganism(cOrganism* org, const cPopulationCell& cell, const cMerit& merit, int lineage) {
	assert(org!=0);
	int dst_world=-1;
	
	// which world is this organism migrating to?
	switch(GetConfig().BIRTH_METHOD.Get()) {
		case POSITION_OFFSPRING_RANDOM: { // spatial, random in neighborhood
			int x, y;
			cell.GetPosition(x,y);
			if(x == 0) {
				// migrate left
				dst_world = m_mpi_world.rank() - 1;
			} else if(x == (GetConfig().WORLD_X.Get()-1)) {
				// migrate right
				dst_world = m_mpi_world.rank() + 1;
			} else if(y == 0) {
				// migrate down
				dst_world = m_mpi_world.rank() - m_universe_dim;
			} else if(y == (GetConfig().WORLD_Y.Get()-1)) {
				// migrate up
				dst_world = m_mpi_world.rank() + m_universe_dim;
			}
			break;
		}
		case POSITION_OFFSPRING_FULL_SOUP_RANDOM: { // mass action
			// prevent a migration back to this same world, unless this is the only world
			// we have:
			if(m_mpi_world.size() == 1) {
				dst_world = 0;
			} else {
				dst_world = GetRandom().GetInt(m_mpi_world.size()-1);
				if (dst_world >= m_mpi_world.rank()) {
					++dst_world;
				}
			}
			break;
		}
		default: {
			GetDriver().RaiseFatalException(-1, "Avida-MP only supports BIRTH_METHODS 0 (POSITION_OFFSPRING_RANDOM) and 4 (POSITION_OFFSPRING_FULL_SOUP_RANDOM).");
		}
	}

	assert(dst_world < m_mpi_world.size());
	assert(dst_world >= 0);

	// the tag is set to the number of messages previously sent; this is to allow
	// the receiver to sort messages for consistency.
	m_reqs.push_back(m_mpi_world.isend(dst_world, m_reqs.size(), migration_message(org, cell, merit.GetDouble(), lineage)));
	
	// stats tracking:
	GetStats().OutgoingMigrant(org);
}


/*! Returns true if an organism should be migrated to a different world.