def Pregel(graph: Graph[V,E], //graph
           initialMsg: M //initial messsage
           vprogf: ((Id,V), M) => V, // vertex program
           sendMsgf: Edge[V,E] => Option[M], // computes msg for each egde
           combinef: (M,M) => M, // combiner
           numIter: Long): Graph[V,E] = {

    // Initialize the messages to all vertices
    var msgs: RDD[(Vid, A)] = graph.vertices.map(v => (v.id, initialMsg))

    // Loop while their are messages
    var i = 0
    while (msgs.count > 0 && i < maxIter) {
        // Receive the message sums on each vertex
        graph = graph.updateVertices(msgs, vprogf)
        // Compute and combine new messages
        msgs = graph.aggregateNeighbors(sendMsgf, combinef)
        i = i + 1
    }
}