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DijkstraBidirectionCH.java
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DijkstraBidirectionCH.java
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/*
* Licensed to GraphHopper GmbH under one or more contributor
* license agreements. See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*
* GraphHopper GmbH 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 com.graphhopper.routing;
import com.carrotsearch.hppc.IntObjectMap;
import com.graphhopper.routing.weighting.Weighting;
import com.graphhopper.storage.Graph;
import com.graphhopper.storage.SPTEntry;
import com.graphhopper.util.EdgeExplorer;
import com.graphhopper.util.EdgeIterator;
/**
* Uses a very simple version of stall-on-demand (SOD) for CH queries to prevent exploring nodes that can not be part
* of a shortest path. When a node that is about to be settled is stallable it is not expanded, but no further search
* for neighboring stallable nodes is performed.
*
* @author easbar
*/
public class DijkstraBidirectionCH extends DijkstraBidirectionCHNoSOD {
public DijkstraBidirectionCH(Graph graph, Weighting weighting) {
super(graph, weighting);
}
@Override
protected boolean fromEntryCanBeSkipped() {
return entryIsStallable(currFrom, bestWeightMapFrom, inEdgeExplorer, false);
}
@Override
protected boolean toEntryCanBeSkipped() {
return entryIsStallable(currTo, bestWeightMapTo, outEdgeExplorer, true);
}
@Override
public String getName() {
return "dijkstrabi|ch";
}
@Override
public String toString() {
return getName() + "|" + weighting;
}
private boolean entryIsStallable(SPTEntry entry, IntObjectMap<SPTEntry> bestWeightMap, EdgeExplorer edgeExplorer,
boolean reverse) {
// We check for all 'incoming' edges if we can prove that the current node (that is about to be settled) is
// reached via a suboptimal path. We do this regardless of the CH level of the adjacent nodes.
EdgeIterator iter = edgeExplorer.setBaseNode(entry.adjNode);
while (iter.next()) {
int traversalKey = traversalMode.createTraversalKey(iter, reverse);
SPTEntry adjNode = bestWeightMap.get(traversalKey);
if (adjNode != null &&
adjNode.weight + weighting.calcWeight(iter, !reverse, getIncomingEdge(entry)) < entry.weight) {
return true;
}
}
return false;
}
}