// read vertex and edge data
DataSet<Tuple1<Long>> vertices = env.readCsvFile(verticesPath).types(Long.class);
DataSet<Tuple2<Long, Long>> edges = env.readCsvFile(edgesPath).fieldDelimiter(' ').types(Long.class, Long.class)
.flatMap(new UndirectEdge());
// assign the initial components (equal to the vertex id)
DataSet<Tuple2<Long, Long>> verticesWithInitialId = vertices.map(new DuplicateValue<Long>());
// open a delta iteration