Lata code snippet

graphlab.cpp

GlobalAddress<Graph> g;

///////////////////////////////////////////////
// GraphLab synchronous engine: scatter phase

// loop over all vertices in graph
forall(g, [=](Vertex& v){
  // only scatter from vertices that have been signaled to do scatter
  if (v->active_minor_step) {
    v->active_minor_step = false;

    // copy the VertexProgram state to allow it to be captured and used in the delegate
    auto prog_copy = prog(v);
    
    // loop over the adjacency list for 'v'
    forall<async>(adj(g,v), [=](Edge& e){
      auto e_id = e.id;
      auto e_data = e.data;
      
      // atomically visit remote vertex
      // executes atomically
      delegate<async>(e.ga, [=](Vertex& ve){
        auto local_e_data = e_data;
        Edge e = { e_id, g->vs+e_id, local_e_data };
        auto gather_delta = prog_copy.scatter(e, ve);
        prog(ve).post_delta(gather_delta);
      });
      // synchronizes with the outermost loop
    });
  }
});
// all scatters completed