| /* |
| * 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.hugegraph.job.computer; |
| |
| import java.util.Map; |
| |
| import org.apache.hugegraph.util.E; |
| import org.apache.hugegraph.util.ParameterUtil; |
| |
| import com.google.common.collect.ImmutableMap; |
| |
| public class PageRankComputer extends AbstractComputer { |
| |
| public static final String PAGE_RANK = "page_rank"; |
| |
| public static final String ALPHA = "alpha"; |
| public static final double DEFAULT_ALPHA = 0.15D; |
| |
| @Override |
| public String name() { |
| return PAGE_RANK; |
| } |
| |
| @Override |
| public String category() { |
| return CATEGORY_RANK; |
| } |
| |
| @Override |
| public void checkParameters(Map<String, Object> parameters) { |
| maxSteps(parameters); |
| alpha(parameters); |
| precision(parameters); |
| } |
| |
| @Override |
| protected Map<String, Object> checkAndCollectParameters( |
| Map<String, Object> parameters) { |
| return ImmutableMap.of(MAX_STEPS, maxSteps(parameters), |
| ALPHA, alpha(parameters), |
| PRECISION, precision(parameters)); |
| } |
| |
| private static double alpha(Map<String, Object> parameters) { |
| if (!parameters.containsKey(ALPHA)) { |
| return DEFAULT_ALPHA; |
| } |
| double alpha = ParameterUtil.parameterDouble(parameters, ALPHA); |
| E.checkArgument(alpha > 0 && alpha < 1, |
| "The value of %s must be (0, 1), but got %s", |
| ALPHA, alpha); |
| return alpha; |
| } |
| } |