[BUG] get_topology function does not destroy hwloc_topology_t instance, leading to Too many open files error and segfault

[GuilloteauQ]

The get_topology function is responsible to set up several vectors with the correct size based on the underlying topology.

daphne/src/runtime/local/vectorized/MTWrapper.h

Lines 87 to 96 in ccba938

	void get_topology(std::vector<int> &physicalIds, std::vector<int> &uniqueThreads, std::vector<int> &responsibleThreads) {
	hwloc_topology_t topology;
	hwloc_topology_init(&topology);
	hwloc_topology_load(topology);
	physicalIds.resize(hwloc_get_nbobjs_by_type(topology, HWLOC_OBJ_PACKAGE));
	uniqueThreads.resize(hwloc_get_nbobjs_by_type(topology, HWLOC_OBJ_CORE));
	responsibleThreads.resize(hwloc_get_nbobjs_by_type(topology, HWLOC_OBJ_PU));
	}

However, the topology object keeps a file open while alive, and this object is not destroyed.
This issue leads to a sneaky Too many open fileserror, and makes hwloc return nonsense values which cause segfault later on in the program.

get_topology should call at the end of the scope by calling

hwloc_topology_destroy(topology);

doc: https://www.open-mpi.org/projects/hwloc/doc/v2.10.0/a00139.php#ga9f34a640b6fd28d23699d4d084667b15

I will prepare a pull request