htm.core

Class HTMedge

java.lang.Object

htm.core.HTMedge

public class HTMedge
extends Object

Edge class The Edges are needed at construction time of the spatial index. They are used to generate the midpoints of the nodes in a certain layer. The interface is simple: construct a class giving it the HTMindexImp and the layer number. Then call makeMidPoints. The HTMindexImp will then have its midpoint constructed in every QuadNode.

  Current Version
  ===============
  ID:   $Id: HTMedge.java,v 1.2 2003/02/19 15:46:11 womullan Exp $
  Revision:     $Revision: 1.2 $
  Date/time:    $Date: 2003/02/19 15:46:11 $
 

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	HTMedge.Edge

Field Summary

Fields

Modifier and Type	Field and Description
(package private) HTMedge.Edge[]	edges_
(package private) int	index_
(package private) Layer	layer_
(package private) HTMedge.Edge[]	lTab_
(package private) HTMindexImp	tree_

Constructor Summary

Constructors

Constructor and Description
HTMedge(HTMindexImp tree, int layerindex) Constructor : give the tree and its layer

Method Summary

Modifier and Type	Method and Description
(package private) HTMedge.Edge	edgeMatch(HTMedge.Edge em) edgeMatch: fast lookup using the first index em->start_.
(package private) int	getMidPoint(HTMedge.Edge em) getMidPoint: compute the midpoint of the edge using vector algebra and return its index in the vertex list
(package private) void	insertLookup(HTMedge.Edge em) insertLookup: insert the edge em into the lookup table.
(package private) void	makeMidPoints() makeMidPoints: interface to this class.
(package private) int	newEdge(int emindex, int index, int k) Make a new edge, in the temporary edges_ at emindex, at node_[index] using the k'th side.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

tree_

HTMindexImp tree_

lTab_

HTMedge.Edge[] lTab_

edges_

HTMedge.Edge[] edges_

index_

int index_

layer_

Layer layer_

Constructor Detail

HTMedge

HTMedge(HTMindexImp tree,
        int layerindex)

Constructor : give the tree and its layer

Method Detail

makeMidPoints

void makeMidPoints()

makeMidPoints: interface to this class. Set midpoints of every node in this layer.

newEdge

int newEdge(int emindex,
            int index,
            int k)

Make a new edge, in the temporary edges_ at emindex, at node_[index] using the k'th side. Since every edge belongs to two faces, we have to check wether an edge has been already processed or not (i.e. the midpoint has been constructed or not). We have a lookup table for this purpose. Every edge is stored at lTab[start_]. There may be up to 6 edges in every vertex[start_] so if that table place is occupied, store it in the next table position (and so on). So we only have to look up 6 positions at most.

insertLookup

void insertLookup(HTMedge.Edge em)

insertLookup: insert the edge em into the lookup table. indexed by em->start_. Every vertex has at most 6 edges, so only that much lookup needs to be done.

edgeMatch

HTMedge.Edge edgeMatch(HTMedge.Edge em)

edgeMatch: fast lookup using the first index em->start_. return pointer to edge if matches, null if not.

getMidPoint

int getMidPoint(HTMedge.Edge em)

getMidPoint: compute the midpoint of the edge using vector algebra and return its index in the vertex list