/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* MiddleOutConstructor.java
* Copyright (C) 2007 University of Waikato, Hamilton, New Zealand
*/
package weka.core.neighboursearch.balltrees;
import weka.core.Instance;
import weka.core.DenseInstance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.Randomizable;
import weka.core.RevisionHandler;
import weka.core.RevisionUtils;
import weka.core.TechnicalInformation;
import weka.core.TechnicalInformationHandler;
import weka.core.Utils;
import weka.core.TechnicalInformation.Field;
import weka.core.TechnicalInformation.Type;
import java.util.Enumeration;
import java.util.Random;
import java.util.Vector;
import java.util.ArrayList;
import java.util.Iterator;
import java.io.Serializable;
/**
<!-- globalinfo-start -->
* The class that builds a BallTree middle out.<br/>
* <br/>
* For more information see also:<br/>
* <br/>
* Andrew W. Moore: The Anchors Hierarchy: Using the Triangle Inequality to Survive High Dimensional Data. In: UAI '00: Proceedings of the 16th Conference on Uncertainty in Artificial Intelligence, San Francisco, CA, USA, 397-405, 2000.<br/>
* <br/>
* Ashraf Masood Kibriya (2007). Fast Algorithms for Nearest Neighbour Search. Hamilton, New Zealand.
* <p/>
<!-- globalinfo-end -->
*
<!-- technical-bibtex-start -->
* BibTeX:
* <pre>
* @inproceedings{Moore2000,
* address = {San Francisco, CA, USA},
* author = {Andrew W. Moore},
* booktitle = {UAI '00: Proceedings of the 16th Conference on Uncertainty in Artificial Intelligence},
* pages = {397-405},
* publisher = {Morgan Kaufmann Publishers Inc.},
* title = {The Anchors Hierarchy: Using the Triangle Inequality to Survive High Dimensional Data},
* year = {2000}
* }
*
* @mastersthesis{Kibriya2007,
* address = {Hamilton, New Zealand},
* author = {Ashraf Masood Kibriya},
* school = {Department of Computer Science, School of Computing and Mathematical Sciences, University of Waikato},
* title = {Fast Algorithms for Nearest Neighbour Search},
* year = {2007}
* }
* </pre>
* <p/>
<!-- technical-bibtex-end -->
*
<!-- options-start -->
* Valid options are: <p/>
*
* <pre> -S <num>
* The seed for the random number generator used
* in selecting random anchor.
* (default: 1)</pre>
*
* <pre> -R
* Use randomly chosen initial anchors.</pre>
*
<!-- options-end -->
*
* @author Ashraf M. Kibriya (amk14[at-the-rate]cs[dot]waikato[dot]ac[dot]nz)
* @version $Revision: 5987 $
*/
public class MiddleOutConstructor
extends BallTreeConstructor
implements Randomizable, TechnicalInformationHandler {
/** for serialization. */
private static final long serialVersionUID = -8523314263062524462L;
/** Seed form random number generator. */
protected int m_RSeed = 1;
/**
* The random number generator for selecting
* the first anchor point randomly
* (if selecting randomly).
*/
protected Random rand = new Random(m_RSeed);
/**
* The radius of the smallest ball enclosing all the data points.
*/
private double rootRadius = -1;
/**
* True if the initial anchor is chosen randomly. False if it is the furthest
* point from the mean/centroid.
*/
protected boolean m_RandomInitialAnchor = true;
/**
* Creates a new instance of MiddleOutConstructor.
*/
public MiddleOutConstructor() {
}
/**
* Returns a string describing this nearest neighbour search algorithm.
*
* @return a description of the algorithm for displaying in the
* explorer/experimenter gui
*/
public String globalInfo() {
return
"The class that builds a BallTree middle out.\n\n"
+ "For more information see also:\n\n"
+ getTechnicalInformation().toString();
}
/**
* Returns an instance of a TechnicalInformation object, containing detailed
* information about the technical background of this class, e.g., paper
* reference or book this class is based on.
*
* @return the technical information about this class
*/
public TechnicalInformation getTechnicalInformation() {
TechnicalInformation result;
TechnicalInformation additional;
result = new TechnicalInformation(Type.INPROCEEDINGS);
result.setValue(Field.AUTHOR, "Andrew W. Moore");
result.setValue(Field.TITLE, "The Anchors Hierarchy: Using the Triangle Inequality to Survive High Dimensional Data");
result.setValue(Field.YEAR, "2000");
result.setValue(Field.BOOKTITLE, "UAI '00: Proceedings of the 16th Conference on Uncertainty in Artificial Intelligence");
result.setValue(Field.PAGES, "397-405");
result.setValue(Field.PUBLISHER, "Morgan Kaufmann Publishers Inc.");
result.setValue(Field.ADDRESS, "San Francisco, CA, USA");
additional = result.add(Type.MASTERSTHESIS);
additional.setValue(Field.AUTHOR, "Ashraf Masood Kibriya");
additional.setValue(Field.TITLE, "Fast Algorithms for Nearest Neighbour Search");
additional.setValue(Field.YEAR, "2007");
additional.setValue(Field.SCHOOL, "Department of Computer Science, School of Computing and Mathematical Sciences, University of Waikato");
additional.setValue(Field.ADDRESS, "Hamilton, New Zealand");
return result;
}
/**
* Builds a ball tree middle out.
* @return The root node of the tree.
* @throws Exception If there is problem building
* the tree.
*/
public BallNode buildTree() throws Exception {
m_NumNodes = m_MaxDepth = m_NumLeaves = 0;
if(rootRadius == -1) {
rootRadius = BallNode.calcRadius(m_InstList, m_Instances,
BallNode.calcCentroidPivot(m_InstList, m_Instances),
m_DistanceFunction);
}
BallNode root = buildTreeMiddleOut(0, m_Instances.numInstances()-1);
return root;
}
/**
* Builds a ball tree middle out from the
* portion of the master index array given
* by supplied start and end index.
* @param startIdx The start of the portion
* in master index array.
* @param endIdx the end of the portion in
* master index array.
* @return The root node of the built tree.
* @throws Exception If there is some
* problem building the tree.
*/
protected BallNode buildTreeMiddleOut(int startIdx, int endIdx)
throws Exception {
Instance pivot;
double radius;
Vector<TempNode> anchors;
int numInsts = endIdx - startIdx + 1;
int numAnchors = (int) Math.round(Math.sqrt(numInsts));
//create anchor's hierarchy
if (numAnchors > 1) {
pivot = BallNode.calcCentroidPivot(startIdx, endIdx, m_InstList,m_Instances);
radius = BallNode.calcRadius(startIdx, endIdx, m_InstList, m_Instances,
pivot, m_DistanceFunction);
if(numInsts <= m_MaxInstancesInLeaf ||
(rootRadius==0 ? true : radius/rootRadius < m_MaxRelLeafRadius)) { //just make a leaf don't make anchors hierarchy
BallNode node = new BallNode(startIdx, endIdx, m_NumNodes,pivot, radius);
return node;
}
anchors = new Vector<TempNode>(numAnchors);
createAnchorsHierarchy(anchors, numAnchors, startIdx, endIdx);
BallNode node = mergeNodes(anchors, startIdx, endIdx);
buildLeavesMiddleOut(node);
return node;
}// end anchors hierarchy
else {
BallNode node = new BallNode(startIdx, endIdx, m_NumNodes,
(pivot=BallNode.calcCentroidPivot(startIdx, endIdx,
m_InstList, m_Instances)),
BallNode.calcRadius(startIdx, endIdx, m_InstList,
m_Instances, pivot,
m_DistanceFunction)
);
return node;
}
}
/**
* Creates an anchors hierarchy from a portion
* of master index array.
*
* @param anchors The vector for putting the anchors
* into.
* @param numAnchors The number of anchors to create.
* @param startIdx The start of the portion of master
* index array.
* @param endIdx The end of the portion of master
* index array.
* @throws Exception If there is some problem in creating
* the hierarchy.
*/
protected void createAnchorsHierarchy(Vector<TempNode> anchors, final int numAnchors,
final int startIdx, final int endIdx)
throws Exception {
TempNode anchr1 = m_RandomInitialAnchor ?
getRandomAnchor(startIdx, endIdx) :
getFurthestFromMeanAnchor(startIdx, endIdx);
TempNode amax = anchr1; //double maxradius = anchr1.radius;
TempNode newAnchor;
Vector<double[]> anchorDistances = new Vector<double[]>(numAnchors-1);
anchors.add(anchr1);
//creating anchors
while(anchors.size() < numAnchors) {
//create new anchor
newAnchor = new TempNode();
newAnchor.points = new MyIdxList();
Instance newpivot = m_Instances.instance(((ListNode)amax.points.getFirst()).idx);
newAnchor.anchor = newpivot;
newAnchor.idx = ((ListNode)amax.points.getFirst()).idx;
setInterAnchorDistances(anchors, newAnchor, anchorDistances);
if(stealPoints(newAnchor, anchors, anchorDistances)) //if points stolen
newAnchor.radius = ((ListNode)newAnchor.points.getFirst()).distance;
else
newAnchor.radius = 0.0;
anchors.add(newAnchor);
//find new amax
amax = (TempNode)anchors.elementAt(0);
for(int i=1; i<anchors.size(); i++) {
newAnchor = (TempNode)anchors.elementAt(i);
if(newAnchor.radius > amax.radius)
amax = newAnchor;
}//end for
}//end while
}
/**
* Applies the middle out build procedure to
* the leaves of the tree. The leaf nodes
* should be the ones that were created by
* createAnchorsHierarchy(). The process
* continues recursively for the leaves
* created for each leaf of the given tree
* until for some leaf node <=
* m_MaxInstancesInLeaf instances remain
* in the leaf.
*
* @param node The root of the tree.
* @throws Exception If there is some problem
* in building the tree leaves.
*/
protected void buildLeavesMiddleOut(BallNode node) throws Exception {
if(node.m_Left!=null && node.m_Right!=null) { //if an internal node
buildLeavesMiddleOut(node.m_Left);
buildLeavesMiddleOut(node.m_Right);
}
else if(node.m_Left!=null || node.m_Right!=null) {
throw new Exception("Invalid leaf assignment. Please check code");
}
else { //if node is a leaf
BallNode n2 = buildTreeMiddleOut(node.m_Start, node.m_End);
if(n2.m_Left!=null && n2.m_Right!=null) {
node.m_Left = n2.m_Left;
node.m_Right = n2.m_Right;
buildLeavesMiddleOut(node);
//the stopping condition in buildTreeMiddleOut will stop the recursion,
//where it won't split a node at all, and we won't recurse here.
}
else if(n2.m_Left!=null || n2.m_Right!=null)
throw new Exception("Invalid leaf assignment. Please check code");
}
}
/**
* Merges nodes created by createAnchorsHierarchy()
* into one top node.
*
* @param list List of anchor nodes.
* @param startIdx The start of the portion of
* master index array containing these anchor
* nodes.
* @param endIdx The end of the portion of master
* index array containing these anchor nodes.
* @return The top/root node after merging
* the given anchor nodes.
* @throws Exception IF there is some problem in
* merging.
*/
protected BallNode mergeNodes(Vector<TempNode> list, int startIdx, int endIdx)
throws Exception {
for(int i=0; i<list.size(); i++) {
TempNode n = (TempNode) list.get(i);
n.anchor = calcPivot(n.points, new MyIdxList(), m_Instances);
n.radius = calcRadius(n.points, new MyIdxList(), n.anchor, m_Instances);
}
double minRadius, tmpRadius; //tmpVolume, minVolume;
Instance pivot, minPivot=null;
TempNode parent; int min1=-1, min2=-1;
while(list.size() > 1) { //main merging loop
minRadius=Double.POSITIVE_INFINITY;
for(int i=0; i<list.size(); i++) {
TempNode first = (TempNode) list.get(i);
for(int j=i+1; j<list.size(); j++) {
TempNode second = (TempNode) list.get(j);
pivot = calcPivot(first, second, m_Instances);
tmpRadius = calcRadius(first, second); //calcRadius(first.points, second.points, pivot, m_Instances);
if(tmpRadius < minRadius) { //(tmpVolume < minVolume) {
minRadius = tmpRadius; //minVolume = tmpVolume;
minPivot = pivot;
min1=i; min2=j;
//minInstList = tmpInstList;
}
}//end for(j)
}//end for(i)
parent = new TempNode();
parent.left = (TempNode) list.get(min1);
parent.right = (TempNode) list.get(min2);
parent.anchor = minPivot;
parent.radius = calcRadius(parent.left.points, parent.right.points, minPivot, m_Instances); //minRadius;
parent.points = parent.left.points.append(parent.left.points, parent.right.points);
list.remove(min1); list.remove(min2-1);
list.add(parent);
}//end while
TempNode tmpRoot = (TempNode)list.get(list.size()-1);
if((endIdx-startIdx+1)!= tmpRoot.points.length()) {
throw new Exception("Root nodes instance list is of irregular length. " +
"Please check code. Length should " +
"be: " + (endIdx-startIdx+1) +
" whereas it is found to be: "+tmpRoot.points.length());
}
for(int i=0; i<tmpRoot.points.length(); i++) {
m_InstList[startIdx+i] = ((ListNode)tmpRoot.points.get(i)).idx;
}
BallNode node = makeBallTreeNodes(tmpRoot, startIdx, endIdx, 0);
return node;
}
/**
* Makes BallTreeNodes out of TempNodes.
*
* @param node The root TempNode
* @param startidx The start of the portion of
* master index array the TempNodes
* are made from.
* @param endidx The end of the portion of
* master index array the TempNodes are
* made from.
* @param depth The depth in the tree where
* this root TempNode is made (needed when
* leaves of a tree deeper down are built
* middle out).
* @return The root BallTreeNode.
*/
protected BallNode makeBallTreeNodes(TempNode node, int startidx,
int endidx, int depth) {
BallNode ball=null;
if(node.left!=null && node.right!=null) { //make an internal node
ball = new BallNode(
startidx, endidx, m_NumNodes,
node.anchor,
node.radius
);
m_NumNodes += 1;
ball.m_Left = makeBallTreeNodes(node.left, startidx, startidx+node.left.points.length()-1, depth+1);
ball.m_Right= makeBallTreeNodes(node.right, startidx+node.left.points.length(), endidx, depth+1);
m_MaxDepth++;
}
else { //make a leaf node
ball = new BallNode(startidx, endidx, m_NumNodes,
node.anchor,
node.radius
);
m_NumNodes += 1;
m_NumLeaves += 1;
}
return ball;
}
/**
* Returns an anchor point which is furthest from the
* mean point for a given set of points (instances)
* (The anchor instance is chosen from the given
* set of points).
*
* @param startIdx The start index of the points
* for which anchor point is required.
* @param endIdx The end index of the points for
* which anchor point is required.
* @return The furthest point/instance from the mean
* of given set of points.
*/
protected TempNode getFurthestFromMeanAnchor(int startIdx, int endIdx) {
TempNode anchor = new TempNode();
Instance centroid = BallNode.calcCentroidPivot(startIdx, endIdx, m_InstList,
m_Instances);
Instance temp;
double tmpr;
anchor.radius = Double.NEGATIVE_INFINITY;
for(int i=startIdx; i<=endIdx; i++) {
temp = m_Instances.instance(m_InstList[i]);
tmpr = m_DistanceFunction.distance(centroid, temp);
if(tmpr > anchor.radius) {
anchor.idx = m_InstList[i];
anchor.anchor = temp;
anchor.radius = tmpr;
}
}
setPoints(anchor, startIdx, endIdx, m_InstList);
return anchor;
}
/**
* Returns a random anchor point/instance from a
* given set of points/instances.
*
* @param startIdx The start index of the points
* for which anchor is required.
* @param endIdx The end index of the points for
* which anchor is required.
* @return The random anchor point/instance
* for the given set of
*/
protected TempNode getRandomAnchor(int startIdx, int endIdx) {
TempNode anchr1 = new TempNode();
anchr1.idx = m_InstList[startIdx+rand.nextInt((endIdx-startIdx+1))];
anchr1.anchor = m_Instances.instance(anchr1.idx);
setPoints(anchr1, startIdx, endIdx, m_InstList);
anchr1.radius = ((ListNode)anchr1.points.getFirst()).distance;
return anchr1;
}
/**
* Sets the points of an anchor node. It takes the
* indices of points from the given portion of
* an index array and stores those indices, together
* with their distances to the given anchor node,
* in the point index list of the anchor node.
*
* @param node The node in which the points are
* needed to be set.
* @param startIdx The start of the portion in
* the given index array (the master index
* array).
* @param endIdx The end of the portion in the
* given index array.
* @param indices The index array.
*/
public void setPoints(TempNode node, int startIdx, int endIdx, int[] indices) {
node.points = new MyIdxList();
Instance temp; double dist;
for(int i=startIdx; i<=endIdx; i++) {
temp = m_Instances.instance(indices[i]);
dist = m_DistanceFunction.distance(node.anchor, temp);
node.points.insertReverseSorted(indices[i], dist);
}
}
/**
* Sets the distances of a supplied new
* anchor to all the rest of the
* previous anchor points.
* @param anchors The old anchor points.
* @param newAnchor The new anchor point.
* @param anchorDistances The vector to
* store the distances of newAnchor to
* each of the old anchors.
* @throws Exception If there is some
* problem in calculating the distances.
*/
public void setInterAnchorDistances(Vector<TempNode> anchors, TempNode newAnchor,
Vector<double[]> anchorDistances) throws Exception {
double[] distArray = new double[anchors.size()];
for(int i=0; i<anchors.size(); i++) {
Instance anchr = ((TempNode)anchors.elementAt(i)).anchor;
distArray[i] = m_DistanceFunction.distance(anchr, newAnchor.anchor);
}
anchorDistances.add(distArray);
}
/**
* Removes points from old anchors that
* are nearer to the given new anchor and
* adds them to the list of points of the
* new anchor.
* @param newAnchor The new anchor.
* @param anchors The old anchors.
* @param anchorDistances The distances
* of new anchor to each of the old
* anchors.
* @return true if any points are removed
* from the old anchors
*/
public boolean stealPoints(TempNode newAnchor, Vector anchors,
Vector anchorDistances) {
int maxIdx = -1;
double maxDist = Double.NEGATIVE_INFINITY;
double[] distArray = (double[])anchorDistances.lastElement();
for(int i=0; i<distArray.length; i++)
if(maxDist < distArray[i]) {
maxDist = distArray[i]; maxIdx = i;
}
boolean anyPointsStolen=false, pointsStolen=false;
TempNode anchorI;
double newDist, distI, interAnchMidDist;
Instance newAnchInst = newAnchor.anchor, anchIInst;
for(int i=0; i<anchors.size(); i++) {
anchorI = (TempNode)anchors.elementAt(i);
anchIInst = anchorI.anchor;
pointsStolen = false;
interAnchMidDist = m_DistanceFunction.distance(newAnchInst, anchIInst)/2D;
for(int j=0; j<anchorI.points.length(); j++) {
ListNode tmp = (ListNode) anchorI.points.get(j);
//break if we reach a point whose distance is less than the midpoint
//of inter anchor distance
if(tmp.distance < interAnchMidDist)
break;
//else test if this point can be stolen by the new anchor
newDist = m_DistanceFunction.distance(newAnchInst,
m_Instances.instance(tmp.idx));
distI = tmp.distance;
if(newDist < distI) {
newAnchor.points.insertReverseSorted(tmp.idx, newDist);
anchorI.points.remove(j);
anyPointsStolen=pointsStolen=true;
}
}
if (pointsStolen)
anchorI.radius = ((ListNode)anchorI.points.getFirst()).distance;
}//end for
return anyPointsStolen;
}//end stealPoints()
/**
/**
* Calculates the centroid pivot of a node based on its
* two child nodes (if merging two nodes).
* @param node1 The first child.
* @param node2 The second child.
* @param insts The set of instances on which the tree
* is being built (as dataset header information is
* required).
* @return The centroid pivot of a node.
*/
public Instance calcPivot(TempNode node1, TempNode node2, Instances insts) {
int classIdx = m_Instances.classIndex();
double[] attrVals = new double[insts.numAttributes()];
Instance temp;
double anchr1Ratio = (double)node1.points.length() /
(node1.points.length()+node2.points.length()),
anchr2Ratio = (double)node2.points.length() /
(node1.points.length()+node2.points.length()); ;
for(int k=0; k<node1.anchor.numValues(); k++) {
if(node1.anchor.index(k)==classIdx)
continue;
attrVals[k] += node1.anchor.valueSparse(k)*anchr1Ratio;
}
for(int k=0; k<node2.anchor.numValues(); k++) {
if(node2.anchor.index(k)==classIdx)
continue;
attrVals[k] += node2.anchor.valueSparse(k)*anchr2Ratio;
}
temp = new DenseInstance(1.0, attrVals);
return temp;
}
/**
* Calculates the centroid pivot of a node based on
* the list of points that it contains (tbe two
* lists of its children are provided).
* @param list1 The point index list of first child.
* @param list2 The point index list of second
* child.
* @param insts The insts object on which the tree
* is being built (for header information).
* @return The centroid pivot of the node.
*/
public Instance calcPivot(MyIdxList list1, MyIdxList list2, Instances insts) {
int classIdx = m_Instances.classIndex();
double[] attrVals = new double[insts.numAttributes()];
Instance temp;
for(int i=0; i<list1.length(); i++) {
temp = insts.instance(((ListNode)list1.get(i)).idx);
for(int k=0; k<temp.numValues(); k++) {
if(temp.index(k)==classIdx)
continue;
attrVals[k] += temp.valueSparse(k);
}
}
for(int j=0; j<list2.length(); j++) {
temp = insts.instance(((ListNode)list2.get(j)).idx);
for(int k=0; k<temp.numValues(); k++) {
if(temp.index(k)==classIdx)
continue;
attrVals[k] += temp.valueSparse(k);
}
}
for(int j=0, numInsts=list1.length()+list2.length();
j < attrVals.length; j++) {
attrVals[j] /= numInsts;
}
temp = new DenseInstance(1.0, attrVals);
return temp;
}
/**
* Calculates the radius of a node based on its two
* child nodes (if merging two nodes).
* @param n1 The first child of the node.
* @param n2 The second child of the node.
* @return The radius of the node.
* @throws Exception
*/
public double calcRadius(TempNode n1, TempNode n2) {
Instance p1 = n1.anchor, p2 = n2.anchor;
double radius = n1.radius + m_DistanceFunction.distance(p1, p2) + n2.radius;
return radius/2;
}
/**
* Calculates the radius of a node based on the
* list of points that it contains (the two lists of
* its children are provided).
* @param list1 The point index list of first child.
* @param list2 The point index list of second child.
* @param pivot The centre/pivot of the node.
* @param insts The instances on which the tree is
* being built (for header info).
* @return The radius of the node.
*/
public double calcRadius(MyIdxList list1, MyIdxList list2,
Instance pivot, Instances insts) {
double radius = Double.NEGATIVE_INFINITY;
for(int i=0; i<list1.length(); i++) {
double dist = m_DistanceFunction.distance(pivot,
insts.instance(((ListNode)list1.get(i)).idx));
if(dist>radius)
radius = dist;
}
for(int j=0; j<list2.length(); j++) {
double dist = m_DistanceFunction.distance(pivot,
insts.instance(((ListNode)list2.get(j)).idx));
if(dist>radius)
radius = dist;
}
return radius;
}
/**
* Adds an instance to the tree. This implementation of
* MiddleOutConstructor doesn't support addition of
* instances to already built tree, hence it always
* throws an exception.
* @param node The root of the tree to which the
* instance is to be added.
* @param inst The instance to add to the tree.
* @return The updated master index array after
* adding the instance.
* @throws Exception Always as this implementation of
* MiddleOutConstructor doesn't support addition of
* instances after batch construction of the tree.
*/
public int[] addInstance(BallNode node, Instance inst) throws Exception {
throw new Exception("Addition of instances after the tree is built, not " +
"possible with MiddleOutConstructor.");
}
/**
* Sets the maximum number of instances allowed in a leaf.
* @param num The maximum number of instances allowed in
* a leaf.
* @throws Exception If the num is < 2, as the method
* cannot work for < 2 instances.
*/
public void setMaxInstancesInLeaf(int num) throws Exception {
if(num<2)
throw new Exception("The maximum number of instances in a leaf for " +
"using MiddleOutConstructor must be >=2.");
super.setMaxInstancesInLeaf(num);
}
/**
* Sets the instances on which the tree is to be built.
* @param insts The instances on which to build the
* ball tree.
*/
public void setInstances(Instances insts) {
super.setInstances(insts);
rootRadius = -1; //this needs to be re-calculated by buildTree()
}
/**
* Sets the master index array that points to
* instances in m_Instances, so that only this array
* is manipulated, and m_Instances is left
* untouched.
* @param instList The master index array.
*/
public void setInstanceList(int[] instList) {
super.setInstanceList(instList);
rootRadius = -1; //this needs to be re-calculated by buildTree()
}
/**
* Returns the tip text for this property.
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String initialAnchorRandomTipText() {
return "Whether the initial anchor is chosen randomly.";
}
/**
* Gets whether if the initial anchor is chosen randomly.
* @return true if the initial anchor is a random one.
*/
public boolean isInitialAnchorRandom() {
return m_RandomInitialAnchor;
}
/**
* Sets whether if the initial anchor is chosen randomly. If not
* then if it is the furthest point from the mean/centroid.
* @param randomInitialAnchor Should be true if the first
* anchor is to be chosen randomly.
*/
public void setInitialAnchorRandom(boolean randomInitialAnchor) {
m_RandomInitialAnchor = randomInitialAnchor;
}
/**
* Returns the tip text for this property.
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String seedTipText() {
return "The seed value for the random number generator.";
}
/**
* Returns the seed for random number generator.
* @return The random number seed.
*/
public int getSeed() {
return m_RSeed;
}
/**
* Sets the seed for random number generator
* (that is used for selecting the first anchor
* point randomly).
* @param seed The seed.
*/
public void setSeed(int seed) {
m_RSeed = seed;
}
/**
* Returns an enumeration describing the available options.
*
* @return an enumeration of all the available options.
*/
public Enumeration listOptions() {
Vector<Option> newVector = new Vector<Option>();
newVector.addElement(new Option(
"\tThe seed for the random number generator used\n"
+ "\tin selecting random anchor.\n"
+ "(default: 1)",
"S", 1, "-S <num>"));
newVector.addElement(new Option(
"\tUse randomly chosen initial anchors.",
"R", 0, "-R"));
return newVector.elements();
}
/**
* Parses a given list of options.
*
<!-- options-start -->
* Valid options are: <p/>
*
* <pre> -S <num>
* The seed for the random number generator used
* in selecting random anchor.
* (default: 1)</pre>
*
* <pre> -R
* Use randomly chosen initial anchors.</pre>
*
<!-- options-end -->
*
* @param options the list of options as an array of strings
* @throws Exception if an option is not supported
**/
public void setOptions(String[] options)
throws Exception {
super.setOptions(options);
String temp = Utils.getOption('S', options);
if(temp.length()>0) {
setSeed(Integer.parseInt(temp));
}
else {
setSeed(1);
}
setInitialAnchorRandom(Utils.getFlag('R', options));
}
/**
* Gets the current settings of this BallTree MiddleOutConstructor.
*
* @return an array of strings suitable for passing to setOptions
*/
public String[] getOptions() {
Vector<String> result;
String[] options;
int i;
result = new Vector<String>();
options = super.getOptions();
for (i = 0; i < options.length; i++)
result.add(options[i]);
result.add("-S");
result.add("" + getSeed());
if(isInitialAnchorRandom())
result.add("-R");
return result.toArray(new String[result.size()]);
}
/**
* Checks whether if the points in an index list
* are in some specified of the master index array.
* @param list The point list.
* @param startidx The start of the portion in
* master index array.
* @param endidx The end of the portion in master
* index array.
* @throws Exception If some point in the point
* list is not in the specified portion of master
* index array.
*/
public void checkIndicesList(MyIdxList list, int startidx, int endidx)
throws Exception {
boolean found;
ListNode node;
for(int i=0; i<list.size(); i++) {
node = (ListNode)list.get(i);
found=false;
for(int j=startidx; j<=endidx; j++) {
if(node.idx==m_InstList[j]) {
found=true;
break;
}
}
if(!found)
throw new Exception("Error: Element "+node.idx+" of the list not in " +
"the array." +
"\nArray: "+printInsts(startidx, endidx)+
"\nList: "+printList(list));
}
}
/**
* For printing indices in some given portion
* of the master index array.
* @param startIdx The start of the portion
* in master index array.
* @param endIdx The end of the portion in
* master index array.
* @return The string containing the indices
* in specified portion of the master index
* array.
*/
public String printInsts(int startIdx, int endIdx) {
StringBuffer bf = new StringBuffer();
try {
bf.append("i: ");
for (int i = startIdx; i <= endIdx; i++) {
if (i == startIdx)
bf.append("" + m_InstList[i]);
else
bf.append(", " + m_InstList[i]);
}
} catch (Exception ex) {
ex.printStackTrace();
}
return bf.toString();
}
/**
* For printing indices in a given point list.
* @param points The point list.
* @return String containing indices of the
* points in the point list.
*/
public String printList(MyIdxList points) {
if(points==null || points.length()==0) return "";
StringBuffer bf = new StringBuffer();
try {
ListNode temp;
for(int i=0; i<points.size(); i++) {
temp = (ListNode) points.get(i);
if(i==0)
bf.append(""+temp.idx);
else
bf.append(", "+temp.idx);
}
} catch(Exception ex) { ex.printStackTrace(); }
return bf.toString();
}
/**
* Returns the revision string.
*
* @return the revision
*/
public String getRevision() {
return RevisionUtils.extract("$Revision: 5987 $");
}
/**
* Temp class to represent either a leaf node or an internal node. Should only
* have two children (could be the case one child is an instance and the
* other another node). Primarily used for anchor nodes. It stores the
* points contained in a node together with their distances to the
* node's centre/anchor point.
*
* @author Ashraf M. Kibriya (amk14[at-the-rate]cs[dot]waikato[dot]ac[dot]nz)
* @version $Revision: 5987 $
*/
protected class TempNode
implements RevisionHandler {
/** The anchor point of the node. */
Instance anchor;
/** The index of the anchor point. */
int idx;
/** The radius of the node. */
double radius;
/** The list of points inside the node. */
MyIdxList points;
/** Node's left child. */
TempNode left;
/** Node's right child. */
TempNode right;
/**
* Returns a string represention of the node.
* @return The string representation of the
* node.
*/
public String toString() {
if(points==null || points.length()==0) return idx+"";
StringBuffer bf = new StringBuffer();
try {
bf.append(idx+" p: ");
ListNode temp;
for(int i=0; i<points.size(); i++) {
temp = (ListNode) points.get(i);
if(i==0)
bf.append(""+temp.idx);
else
bf.append(", "+temp.idx);
}
} catch(Exception ex) { ex.printStackTrace(); }
return bf.toString();
}
/**
* Returns the revision string.
*
* @return the revision
*/
public String getRevision() {
return RevisionUtils.extract("$Revision: 5987 $");
}
}
/**
* An element of MyIdxList. It stores a points index, and
* its distance to some specific point (usually a node's
* anchor point).
*
* @author Ashraf M. Kibriya (amk14[at-the-rate]cs[dot]waikato[dot]ac[dot]nz)
* @version $Revision: 5987 $
*/
protected class ListNode
implements RevisionHandler {
/** The index of the point. */
int idx = -1;
/** The distance of the point to the anchor.*/
double distance = Double.NEGATIVE_INFINITY;
/**
* Constructor.
* @param i The point's index.
* @param d The point's distance to the
* anchor.
*/
public ListNode(int i, double d) {
idx = i;
distance = d;
}
/**
* Returns the revision string.
*
* @return the revision
*/
public String getRevision() {
return RevisionUtils.extract("$Revision: 5987 $");
}
}
/**
* Class implementing a list. It stores indices of
* instances/points, together with their distances to a nodes
* centre/pivot/anchor, in a (reverse sorted) list.
*
* @author Ashraf M. Kibriya (amk14[at-the-rate]cs[dot]waikato[dot]ac[dot]nz)
* @version $Revision: 5987 $
*/
protected class MyIdxList implements Serializable, RevisionHandler {
/** for serialization. */
private static final long serialVersionUID = -2283869109722934927L;
/** The array list backing this list */
protected ArrayList<ListNode> m_List;
/**
* Constructor.
*/
public MyIdxList() {
m_List = new ArrayList<ListNode>();
}
/**
* Constructor for given capacity.
*/
public MyIdxList(int capacity) {
m_List = new ArrayList<ListNode>(capacity);
}
/**
* Returns the first element in the list.
* @return The list's first element.
*/
public ListNode getFirst() {
return m_List.get(0);
}
/**
* Inserts an element in reverse sorted order in
* the list.
* @param idx The index of the point to insert.
* @param distance The distance of the point to
* a node's anchor (this would be used to
* determine the sort order).
*/
public void insertReverseSorted(final int idx, final double distance) {
int i=0;
for (ListNode temp : m_List) {
if(temp.distance < distance)
break;
i++;
}
m_List.add(i, new ListNode(idx, distance));
}
/**
* Returns an element at the specified index in
* the list.
* @param index The index of the element in the
* list.
* @return The element at the given index.
*/
public ListNode get(int index) {
return m_List.get(index);
}
/**
* Removes an element at the specified index
* from the list.
* @param index The index of the element
* in the list to remove.
*/
public void remove(int index) {
m_List.remove(index);
}
/**
* Returns the size of the list.
* @return The size of the list.
*/
public int length() {
return m_List.size();
}
/**
* Returns the size of the list.
* @return The size of the list.
*/
public int size() {
return m_List.size();
}
/**
* Appends one list at the end of the other.
* @param list1 The list to which the other
* list would be appended.
* @param list2 The list to append to the
* other list.
* @return The new list with list2 appended
* to list1.
*/
public MyIdxList append(MyIdxList list1, MyIdxList list2) {
MyIdxList temp = new MyIdxList(list1.size()+list2.size());
temp.m_List.addAll(list1.m_List);
temp.m_List.addAll(list2.m_List);
return temp;
}
/**
* Checks the sorting of a list.
* @param list The list whose sorting is
* to be checked.
* @throws Exception If the list is not
* in (reverse) sorted order.
*/
public void checkSorting(MyIdxList list) throws Exception {
Iterator<ListNode> en = m_List.iterator();
ListNode first=null, second=null;
while(en.hasNext()) {
if(first==null)
first = (ListNode) en.next();
else {
second = (ListNode)en.next();
if(first.distance < second.distance)
throw new Exception("List not sorted correctly." +
" first.distance: " + first.distance +
" second.distance: " + second.distance +
" Please check code.");
}
}
}
/**
* Returns the revision string.
*
* @return the revision
*/
public String getRevision() {
return RevisionUtils.extract("$Revision: 5987 $");
}
}
}