/*
* 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.
*/
package org.apache.giraph.benchmark;
import org.apache.giraph.graph.Vertex;
import org.apache.hadoop.io.FloatWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.NullWritable;
import java.io.IOException;
/**
* Implementation of PageRank in which vertex ids are ints, page rank values
* are floats, and graph is unweighted.
*/
public class PageRankVertex extends Vertex<IntWritable, FloatWritable,
NullWritable, FloatWritable> {
/** Number of supersteps */
public static final String SUPERSTEP_COUNT =
"giraph.pageRank.superstepCount";
@Override
public void compute(Iterable<FloatWritable> messages) throws IOException {
if (getSuperstep() >= 1) {
float sum = 0;
for (FloatWritable message : messages) {
sum += message.get();
}
getValue().set((0.15f / getTotalNumVertices()) + 0.85f * sum);
}
if (getSuperstep() < getConf().getInt(SUPERSTEP_COUNT, 0)) {
sendMessageToAllEdges(
new FloatWritable(getValue().get() / getNumEdges()));
} else {
voteToHalt();
}
}
}