| # 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. |
| |
| from org.apache.giraph.graph import BasicComputation |
| from org.apache.hadoop.io import FloatWritable |
| |
| class PageRank(BasicComputation): |
| SUPERSTEP_COUNT = "giraph.pageRank.superstepCount" |
| |
| def compute(self, vertex, messages): |
| if self.getSuperstep() >= 1: |
| total = 0 |
| for msg in messages: |
| total += msg.get() |
| vertex.getValue().set((0.15 / self.getTotalNumVertices()) + 0.85 * total) |
| |
| if self.getSuperstep() < self.getConf().getInt(self.SUPERSTEP_COUNT, 0): |
| self.sendMessageToAllEdges(vertex, |
| FloatWritable(vertex.getValue().get() / vertex.getNumEdges())) |
| else: |
| vertex.voteToHalt() |