org.apache.lucene.spatial3d.Geo3DPointDistanceComparator Maven / Gradle / Ivy
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/*
* 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.lucene.spatial3d;
import java.io.IOException;
import org.apache.lucene.index.DocValues;
import org.apache.lucene.index.FieldInfo;
import org.apache.lucene.index.LeafReader;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.index.SortedNumericDocValues;
import org.apache.lucene.search.FieldComparator;
import org.apache.lucene.search.LeafFieldComparator;
import org.apache.lucene.search.Scorable;
import org.apache.lucene.spatial3d.geom.DistanceStyle;
import org.apache.lucene.spatial3d.geom.GeoDistanceShape;
import org.apache.lucene.spatial3d.geom.PlanetModel;
import org.apache.lucene.spatial3d.geom.XYZBounds;
/**
* Compares documents by distance from an origin point, using a GeoDistanceShape to compute the
* distance
*
* When the least competitive item on the priority queue changes (setBottom), we recompute a
* bounding box representing competitive distance to the top-N. Then in compareBottom, we can
* quickly reject hits based on bounding box alone without computing distance for every element.
*/
class Geo3DPointDistanceComparator extends FieldComparator implements LeafFieldComparator {
final String field;
final GeoDistanceShape distanceShape;
private final PlanetModel planetModel;
final double[] values;
double bottomDistance;
double topValue;
SortedNumericDocValues currentDocs;
XYZBounds priorityQueueBounds;
// the number of times setBottom has been called (adversary protection)
int setBottomCounter = 0;
public Geo3DPointDistanceComparator(
String field,
final PlanetModel planetModel,
final GeoDistanceShape distanceShape,
int numHits) {
this.field = field;
this.distanceShape = distanceShape;
this.planetModel = planetModel;
this.values = new double[numHits];
}
@Override
public void setScorer(Scorable scorer) {}
@Override
public int compare(int slot1, int slot2) {
return Double.compare(values[slot1], values[slot2]);
}
@Override
public void setBottom(int slot) {
bottomDistance = values[slot];
// make bounding box(es) to exclude non-competitive hits, but start
// sampling if we get called way too much: don't make gobs of bounding
// boxes if comparator hits a worst case order (e.g. backwards distance order)
if (setBottomCounter < 1024 || (setBottomCounter & 0x3F) == 0x3F) {
// Update bounds
final XYZBounds bounds = new XYZBounds();
distanceShape.getDistanceBounds(bounds, DistanceStyle.ARC, bottomDistance);
priorityQueueBounds = bounds;
}
setBottomCounter++;
}
@Override
public void setTopValue(Double value) {
topValue = value.doubleValue();
}
@Override
public int compareBottom(int doc) throws IOException {
if (doc > currentDocs.docID()) {
currentDocs.advance(doc);
}
if (doc < currentDocs.docID()) {
return Double.compare(bottomDistance, Double.POSITIVE_INFINITY);
}
int numValues = currentDocs.docValueCount();
assert numValues > 0;
int cmp = -1;
for (int i = 0; i < numValues; i++) {
long encoded = currentDocs.nextValue();
// Test against bounds.
// First we need to decode...
final double x = planetModel.getDocValueEncoder().decodeXValue(encoded);
final double y = planetModel.getDocValueEncoder().decodeYValue(encoded);
final double z = planetModel.getDocValueEncoder().decodeZValue(encoded);
if (x > priorityQueueBounds.getMaximumX()
|| x < priorityQueueBounds.getMinimumX()
|| y > priorityQueueBounds.getMaximumY()
|| y < priorityQueueBounds.getMinimumY()
|| z > priorityQueueBounds.getMaximumZ()
|| z < priorityQueueBounds.getMinimumZ()) {
continue;
}
cmp =
Math.max(
cmp,
Double.compare(
bottomDistance, distanceShape.computeDistance(DistanceStyle.ARC, x, y, z)));
}
return cmp;
}
@Override
public void copy(int slot, int doc) throws IOException {
values[slot] = computeMinimumDistance(doc);
}
@Override
public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException {
LeafReader reader = context.reader();
FieldInfo info = reader.getFieldInfos().fieldInfo(field);
if (info != null) {
Geo3DDocValuesField.checkCompatible(info);
}
currentDocs = DocValues.getSortedNumeric(reader, field);
return this;
}
@Override
public Double value(int slot) {
// Return the arc distance
return Double.valueOf(values[slot] * planetModel.getMeanRadius());
}
@Override
public int compareTop(int doc) throws IOException {
return Double.compare(topValue, computeMinimumDistance(doc));
}
double computeMinimumDistance(final int doc) throws IOException {
if (doc > currentDocs.docID()) {
currentDocs.advance(doc);
}
double minValue = Double.POSITIVE_INFINITY;
if (doc == currentDocs.docID()) {
final int numValues = currentDocs.docValueCount();
for (int i = 0; i < numValues; i++) {
final long encoded = currentDocs.nextValue();
final double distance =
distanceShape.computeDistance(
DistanceStyle.ARC,
planetModel.getDocValueEncoder().decodeXValue(encoded),
planetModel.getDocValueEncoder().decodeYValue(encoded),
planetModel.getDocValueEncoder().decodeZValue(encoded));
minValue = Math.min(minValue, distance);
}
}
return minValue;
}
}