/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// preprocessing: for each node, group its outgoing links into a bag
graph = select (src,dst)
          from (src,dst) in stream(binary,"tmp/graph.bin")
         group by src;

store graph_size := count(select distinct s
                            from (s,d) in source(binary,"tmp/graph.bin"));

// damping factor
factor = 0.85;

incr repeat nodes = select < id: key, rank: 1.0/graph_size as double, adjacent: al >
                      from (key,al) in graph
       step select ( < id: m.id, rank: n.rank, adjacent: m.adjacent >, true )
              from n in (select < id: key,
                                  rank: (1-factor)/graph_size+factor*sum(rank) >
                           from c in ( select < id: a, rank: n.rank/count(n.adjacent) >
                                         from n in nodes,
                                              a in n.adjacent ),
                                rank = c.rank
                          group by key: c.id),
                   m in nodes
             where n.id = m.id
      limit 5;