public Iterable<IntWritable> getPartitionDestinationVertices(
int partitionId) {
Int2FloatOpenHashMap partitionMap = map.get(partitionId);
List<IntWritable> vertices =
Lists.newArrayListWithCapacity(partitionMap.size());
IntIterator iterator = partitionMap.keySet().iterator();
while (iterator.hasNext()) {
vertices.add(new IntWritable(iterator.nextInt()));
}
return vertices;
}