/*
* Copyright 2013 Alibaba.com All right reserved. This software is the
* confidential and proprietary information of Alibaba.com ("Confidential
* Information"). You shall not disclose such Confidential Information and shall
* use it only in accordance with the terms of the license agreement you entered
* into with Alibaba.com.
*/
package com.alibaba.security.simpleimage.analyze.kdtree;
import java.util.ArrayList;
import java.util.List;
import com.alibaba.security.simpleimage.analyze.reftype.RefDouble;
import com.alibaba.security.simpleimage.analyze.reftype.RefInt;
/**
* 类KDTree.java的实现描述：TODO 类实现描述
*
* @author axman 2013-3-22 下午4:05:00
*/
public class KDTree {
IKDTreeDomain dr; // 当前元素
int splitDim; // 子树分离元素
KDTree left;
KDTree right;
@SuppressWarnings("rawtypes")
public static class BestEntry implements Comparable {
private double dist;
private int distSq;
IKDTreeDomain neighbour;
public IKDTreeDomain getNeighbour() {
return this.neighbour;
}
public int getDistSq() {
return distSq;
}
public void setDistSq(int distSq) {
this.distSq = distSq;
}
public double getDist() {
return dist;
}
public void setDist(double dist) {
this.dist = dist;
}
BestEntry(IKDTreeDomain neighbour, int distSq){
this.neighbour = neighbour;
this.distSq = distSq;
}
BestEntry(IKDTreeDomain neighbour, double dist){
this.neighbour = neighbour;
this.dist = dist;
}
public int compareTo(Object o) {
BestEntry be = (BestEntry) o;
if (distSq < be.distSq) return -1;
if (distSq > be.distSq) return 1;
return 0;
}
}
public static int distanceSq(IKDTreeDomain t1, IKDTreeDomain t2) {
int distance = 0;
for (int n = 0; n < t1.getDimensionCount(); ++n) {
int dimDist = t1.getDimensionElement(n) - t2.getDimensionElement(n);
distance += dimDist * dimDist;
}
return (distance);
}
static class HyperRectangle implements Cloneable {
int[] leftTop;
int[] rightBottom;
int dim;
private HyperRectangle(int dim){
this.dim = dim;
leftTop = new int[dim];
rightBottom = new int[dim];
}
public Object clone() {
HyperRectangle rec = new HyperRectangle(dim);
for (int n = 0; n < dim; ++n) {
rec.leftTop[n] = leftTop[n];
rec.rightBottom[n] = rightBottom[n];
}
return (rec);
}
static HyperRectangle createUniverseRectangle(int dim) {
HyperRectangle rec = new HyperRectangle(dim);
for (int n = 0; n < dim; ++n) {
rec.leftTop[n] = Integer.MIN_VALUE;
rec.rightBottom[n] = Integer.MAX_VALUE;
}
return (rec);
}
HyperRectangle splitAt(int splitDim, int splitVal) {
if (leftTop[splitDim] >= splitVal || rightBottom[splitDim] < splitVal) {
throw (new IllegalArgumentException("SplitAt with splitpoint outside rec"));
}
HyperRectangle r2 = (HyperRectangle) this.clone();
rightBottom[splitDim] = splitVal;
r2.leftTop[splitDim] = splitVal;
return (r2);
}
boolean isIn(IKDTreeDomain target) {
if (target.getDimensionCount() != dim) throw (new IllegalArgumentException("isIn dimension mismatch"));
for (int n = 0; n < dim; ++n) {
int targD = target.getDimensionElement(n);
if (targD < leftTop[n] || targD >= rightBottom[n]) return (false);
}
return (true);
}
boolean isInReach(IKDTreeDomain target, double distRad) {
return (distance(target) < distRad);
}
// Return the distance from the nearest point from within the HR to
// the target point.
double distance(IKDTreeDomain target) {
int closestPointN;
int distance = 0;
// first compute the closest point within hr to the target. if
// this point is within reach of target, then there is an
// intersection between the hypersphere around target with radius
// 'dist' and this hyperrectangle.
for (int n = 0; n < dim; ++n) {
int tI = target.getDimensionElement(n);
int hrMin = leftTop[n];
int hrMax = rightBottom[n];
closestPointN = 0;
if (tI <= hrMin) {
closestPointN = hrMin;
} else if (tI > hrMin && tI < hrMax) {
closestPointN = tI;
} else if (tI >= hrMax) {
closestPointN = hrMax;
}
int dimDist = tI - closestPointN;
distance += dimDist * dimDist;
}
return (Math.sqrt((double) distance));
}
}
static class HREntry implements Comparable<HREntry> {
double dist;
IKDTreeDomain pivot;
HyperRectangle rect;
KDTree tree;
public double getDist() {
return this.dist;
}
public IKDTreeDomain getPivot() {
return this.pivot;
}
public HyperRectangle getRect() {
return this.rect;
}
public KDTree getTree() {
return this.tree;
}
public HREntry(HyperRectangle rect, KDTree tree, IKDTreeDomain pivot, double dist){
this.dist = dist;
this.pivot = pivot;
this.tree = tree;
this.rect = rect;
}
public int compareTo(HREntry o) {
HREntry hre = (HREntry) o;
if (dist < hre.dist) return -1;
if (dist > hre.dist) return 1;
return 0;
}
}
/**
* @param target
* @param refDouble 必须从外部传入一个，且不能是缓存对象
* @return
*/
public IKDTreeDomain nearestNeighbour(IKDTreeDomain target, RefDouble ref) {
HyperRectangle hr = HyperRectangle.createUniverseRectangle(target.getDimensionCount());
IKDTreeDomain nearest = nearestNeighbourI(target, hr, Double.POSITIVE_INFINITY, ref);
Math.sqrt(ref.val);
return (nearest);
}
private IKDTreeDomain nearestNeighbourI(IKDTreeDomain target, HyperRectangle hr, double maxDistSq,
RefDouble resDistSq) {
// Console.WriteLine ("C NearestNeighbourI called");
resDistSq.val = Double.POSITIVE_INFINITY;
IKDTreeDomain pivot = dr;
HyperRectangle leftHr = hr;
HyperRectangle rightHr = leftHr.splitAt(splitDim, pivot.getDimensionElement(splitDim));
HyperRectangle nearerHr, furtherHr;
KDTree nearerKd, furtherKd;
// step 5-7
if (target.getDimensionElement(splitDim) <= pivot.getDimensionElement(splitDim)) {
nearerKd = left;
nearerHr = leftHr;
furtherKd = right;
furtherHr = rightHr;
} else {
nearerKd = right;
nearerHr = rightHr;
furtherKd = left;
furtherHr = leftHr;
}
// step 8
IKDTreeDomain nearest = null;
RefDouble distSq = new RefDouble();
if (nearerKd == null) {
distSq.val = Double.POSITIVE_INFINITY;
} else {
nearest = nearerKd.nearestNeighbourI(target, nearerHr, maxDistSq, distSq);
}
// step 9
maxDistSq = Math.min(maxDistSq, distSq.val);
// step 10
if (furtherHr.isInReach(target, Math.sqrt(maxDistSq))) {
double ptDistSq = KDTree.distanceSq(pivot, target);
if (ptDistSq < distSq.val) {
// steps 10.1.1 to 10.1.3
nearest = pivot;
distSq.val = ptDistSq;
maxDistSq = distSq.val;
}
// step 10.2
RefDouble tempDistSq = new RefDouble();
IKDTreeDomain tempNearest = null;
if (furtherKd == null) {
tempDistSq.val = Double.POSITIVE_INFINITY;
} else {
tempNearest = furtherKd.nearestNeighbourI(target, furtherHr, maxDistSq, tempDistSq);
}
// step 10.3
if (tempDistSq.val < distSq.val) {
nearest = tempNearest;
distSq = tempDistSq;
}
}
resDistSq = distSq;
return (nearest);
}
/**
* @param al
* @return
*/
public static KDTree createKDTree(List<? extends IKDTreeDomain> exset) {
if (exset.size() == 0) return (null);
KDTree cur = new KDTree();
RefInt splitDim = new RefInt();
splitDim.val = cur.splitDim;
cur.dr = goodCandidate(exset, splitDim);
cur.splitDim = splitDim.val;//ou ref cur.splitDim
ArrayList<IKDTreeDomain> leftElems = new ArrayList<IKDTreeDomain>();
ArrayList<IKDTreeDomain> rightElems = new ArrayList<IKDTreeDomain>();
// split the exemplar set into left/right elements relative to the
// splitting dimension
double bound = cur.dr.getDimensionElement(splitDim.val);
for (IKDTreeDomain dom : exset) {
// ignore the current element
if (dom == cur.dr) continue;
if (dom.getDimensionElement(splitDim.val) <= bound) {
leftElems.add(dom);
} else {
rightElems.add(dom);
}
}
// recurse
cur.left = createKDTree(leftElems);
cur.right = createKDTree(rightElems);
return (cur);
}
private static IKDTreeDomain goodCandidate(List<? extends IKDTreeDomain> exset, RefInt splitDim) {
IKDTreeDomain first = exset.get(0);
if (first == null) {
throw (new java.lang.NullPointerException("Not of type IKDTreeDomain "));
}
int dim = first.getDimensionCount();
// initialize temporary hr search min/max values
double[] minHr = new double[dim];
double[] maxHr = new double[dim];
for (int k = 0; k < dim; ++k) {
minHr[k] = Double.POSITIVE_INFINITY;
maxHr[k] = Double.NEGATIVE_INFINITY;
}
for (IKDTreeDomain dom : exset) {
for (int k = 0; k < dim; ++k) {
double dimE = dom.getDimensionElement(k);
if (dimE < minHr[k]) minHr[k] = dimE;
if (dimE > maxHr[k]) maxHr[k] = dimE;
}
}
// find the maximum range dimension
double[] diffHr = new double[dim];
int maxDiffDim = 0;
double maxDiff = 0.0;
for (int k = 0; k < dim; ++k) {
diffHr[k] = maxHr[k] - minHr[k];
if (diffHr[k] > maxDiff) {
maxDiff = diffHr[k];
maxDiffDim = k;
}
}
// the splitting dimension is maxDiffDim
// now find a exemplar as close to the arithmetic middle as possible
double middle = (maxDiff / 2.0) + minHr[maxDiffDim];
IKDTreeDomain exemplar = null;
double exemMinDiff = Double.POSITIVE_INFINITY;
for (IKDTreeDomain dom : exset) {
double curDiff = Math.abs(dom.getDimensionElement(maxDiffDim) - middle);
if (curDiff < exemMinDiff) {
exemMinDiff = curDiff;
exemplar = dom;
}
}
// return the values
splitDim.val = maxDiffDim;
return (exemplar);
}
public ArrayList<BestEntry> nearestNeighbourListBBF(IKDTreeDomain kp, int q, int searchSteps) {
HyperRectangle hr = HyperRectangle.createUniverseRectangle(kp.getDimensionCount());
SortedLimitedList<BestEntry> best = new SortedLimitedList<BestEntry>(q);
SortedLimitedList<HREntry> searchHr = new SortedLimitedList<HREntry>(searchSteps);
RefInt dummyDist = new RefInt();
RefInt step = new RefInt();
dummyDist.val = 0;
step.val = searchSteps;
nearestNeighbourListBBFI(best, q, kp, hr, Integer.MAX_VALUE, dummyDist, searchHr, step);
for (BestEntry be : best)
be.dist = Math.sqrt(be.distSq);
return (best);
}
private IKDTreeDomain nearestNeighbourListBBFI(SortedLimitedList<BestEntry> best, int q, IKDTreeDomain target,
HyperRectangle hr, int maxDistSq, RefInt resDistSq,
SortedLimitedList<HREntry> searchHr, RefInt searchSteps) {
resDistSq.val = Integer.MAX_VALUE;
IKDTreeDomain pivot = dr;
best.add(new BestEntry(dr, KDTree.distanceSq(target, dr)));
HyperRectangle leftHr = hr;
HyperRectangle rightHr = leftHr.splitAt(splitDim, pivot.getDimensionElement(splitDim));
HyperRectangle nearerHr, furtherHr;
KDTree nearerKd, furtherKd;
// step 5-7
if (target.getDimensionElement(splitDim) <= pivot.getDimensionElement(splitDim)) {
nearerKd = left;
nearerHr = leftHr;
furtherKd = right;
furtherHr = rightHr;
} else {
nearerKd = right;
nearerHr = rightHr;
furtherKd = left;
furtherHr = leftHr;
}
// step 8
IKDTreeDomain nearest = null;
RefInt distSq = new RefInt();
searchHr.add(new HREntry(furtherHr, furtherKd, pivot, furtherHr.distance(target)));
// No child, bottom reached!
if (nearerKd == null) {
distSq.val = Integer.MAX_VALUE;
} else {
nearest = nearerKd.nearestNeighbourListBBFI(best, q, target, nearerHr, maxDistSq, distSq, searchHr,
searchSteps);
}
// step 9
if (best.size() >= q) {
maxDistSq = ((BestEntry) best.get(q - 1)).getDistSq();
} else maxDistSq = Integer.MAX_VALUE;
if (searchHr.size() > 0) {
HREntry hre = (HREntry) searchHr.get(0);
searchHr.remove(0);
furtherHr = hre.rect;
furtherKd = hre.tree;
pivot = hre.pivot;
}
// step 10
searchSteps.val -= 1;
if (searchSteps.val > 0 && furtherHr.isInReach(target, Math.sqrt(maxDistSq))) {
int ptDistSq = KDTree.distanceSq(pivot, target);
if (ptDistSq < distSq.val) {
// steps 10.1.1 to 10.1.3
nearest = pivot;
distSq.val = ptDistSq;
maxDistSq = distSq.val;
}
// step 10.2
RefInt tempDistSq = new RefInt();
IKDTreeDomain tempNearest = null;
if (furtherKd == null) {
tempDistSq.val = Integer.MAX_VALUE;
} else {
tempNearest = furtherKd.nearestNeighbourListBBFI(best, q, target, furtherHr, maxDistSq, tempDistSq,
searchHr, searchSteps);
}
// step 10.3
if (tempDistSq.val < distSq.val) {
nearest = tempNearest;
distSq = tempDistSq;
}
}
resDistSq = distSq;
return (nearest);
}
}