/* -*- tab-width: 4 -*-
*
* Electric(tm) VLSI Design System
*
* File: MSTMetric.java
* Written by Team 7: Felix Schmidt, Daniel Lechner
*
* This code has been developed at the Karlsruhe Institute of Technology (KIT), Germany,
* as part of the course "Multicore Programming in Practice: Tools, Models, and Languages".
* Contact instructor: Dr. Victor Pankratius (pankratius@ipd.uka.de)
*
* Copyright (c) 2010 Sun Microsystems and Static Free Software
*
* Electric(tm) 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 3 of the License, or
* (at your option) any later version.
*
* Electric(tm) 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 Electric(tm); see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, Mass 02111-1307, USA.
*/
package com.sun.electric.tool.placement.forceDirected2.metrics;
import com.sun.electric.tool.placement.PlacementFrame.PlacementNetwork;
import com.sun.electric.tool.placement.PlacementFrame.PlacementNode;
import com.sun.electric.tool.placement.PlacementFrame.PlacementPort;
import java.util.HashSet;
import java.util.List;
import java.util.TreeSet;
import java.util.Vector;
/**
* Parallel Placement
*/
public class MSTMetric extends AbstractMetric {
/*
* Kruskal's algorithm finds a minimum spanning tree for a connected
* weighted graph. The program below uses a hard-coded example. You can
* change this to match your problem by changing the edges in the graph. The
* program uses 3 classes. The Kruskal class contains the main method. The
* Edge class represents an edge. The KruskalEdges class contains the edges
* determined by the Kruskal algorithm.
*/
class Edge implements Comparable<Edge> {
PlacementNode vertexA, vertexB;
double weight;
public Edge(PlacementNode vertexA, PlacementNode vertexB, double weight) {
this.vertexA = vertexA;
this.vertexB = vertexB;
this.weight = weight;
}
public int compareTo(Edge edge) {
// == is not compared so that duplicate values are not eliminated.
return (this.weight < edge.weight) ? -1 : 1;
}
public PlacementNode getVertexA() {
return this.vertexA;
}
public PlacementNode getVertexB() {
return this.vertexB;
}
public double getWeight() {
return this.weight;
}
@Override
public String toString() {
return "(" + this.vertexA + ", " + this.vertexB + ") : Weight = " + this.weight;
}
}
class KruskalEdges {
Vector<HashSet<PlacementNode>> vertexGroups = new Vector<HashSet<PlacementNode>>();
TreeSet<Edge> kruskalEdges = new TreeSet<Edge>();
public TreeSet<Edge> getEdges() {
return this.kruskalEdges;
}
HashSet<PlacementNode> getVertexGroup(PlacementNode vertex) {
for (HashSet<PlacementNode> vertexGroup : this.vertexGroups) {
if (vertexGroup.contains(vertex)) {
return vertexGroup;
}
}
return null;
}
/**
* The edge to be inserted has 2 vertices - A and B We maintain a vector
* that contains groups of vertices. We first check if either A or B
* exists in any group If neither A nor B exists in any group We create
* a new group containing both the vertices. If one of the vertices
* exists in a group and the other does not We add the vertex that does
* not exist to the group of the other vertex If both vertices exist in
* different groups We merge the two groups into one All of the above
* scenarios mean that the edge is a valid Kruskal edge In that
* scenario, we will add the edge to the Kruskal edges However, if both
* vertices exist in the same group We do not consider the edge as a
* valid Kruskal edge
*/
public void insertEdge(Edge edge) {
PlacementNode vertexA = edge.getVertexA();
PlacementNode vertexB = edge.getVertexB();
HashSet<PlacementNode> vertexGroupA = this.getVertexGroup(vertexA);
HashSet<PlacementNode> vertexGroupB = this.getVertexGroup(vertexB);
if (vertexGroupA == null) {
this.kruskalEdges.add(edge);
if (vertexGroupB == null) {
HashSet<PlacementNode> htNewVertexGroup = new HashSet<PlacementNode>();
htNewVertexGroup.add(vertexA);
htNewVertexGroup.add(vertexB);
this.vertexGroups.add(htNewVertexGroup);
} else {
vertexGroupB.add(vertexA);
}
} else {
if (vertexGroupB == null) {
vertexGroupA.add(vertexB);
this.kruskalEdges.add(edge);
} else if (vertexGroupA != vertexGroupB) {
vertexGroupA.addAll(vertexGroupB);
this.vertexGroups.remove(vertexGroupB);
this.kruskalEdges.add(edge);
}
}
}
}
public MSTMetric(List<PlacementNode> nodesToPlace, List<PlacementNetwork> allNetworks) {
super(nodesToPlace, allNetworks);
}
@Override
public Double compute() {
double total = 0;
for (PlacementNetwork net : this.allNetworks) {
total += this.compute(net);
}
return new Double(total);
}
/**
*
* @param net
* @return
*/
private double compute(PlacementNetwork net) {
// TreeSet is used to sort the edges before passing to the algorithm
TreeSet<Edge> edges = new TreeSet<Edge>();
for (PlacementPort port1 : net.getPortsOnNet()) {
for (PlacementPort port2 : net.getPortsOnNet()) {
edges.add(new Edge(port1.getPlacementNode(), port2.getPlacementNode(), this.getDistance(port1, port2)));
}
}
KruskalEdges vv = new KruskalEdges();
for (Edge edge : edges) {
vv.insertEdge(edge);
}
double total = 0;
for (Edge edge : vv.getEdges()) {
total += edge.getWeight();
}
return total;
}
/**
* Calculate the distance between two PlacementPort objects
*
* @param port1
* @param port2
* @return
*/
private double getDistance(PlacementPort port1, PlacementPort port2) {
double deltaX = this.getPlacementX(port1) - this.getPlacementX(port2);
double deltaY = this.getPlacementY(port1) - this.getPlacementY(port2);
return Math.sqrt((deltaX * deltaX) + (deltaY * deltaY));
}
@Override
public String getMetricName() {
return "MSTMetric";
}
// Quelle: http://www.krishami.com/programs/java/kruskal.aspx
/**
* Calculate the absolute position of a placementPort (x direction)
*
* @param port
* @return absolut x position
*/
private double getPlacementX(PlacementPort port) {
double nodeX = port.getPlacementNode().getPlacementX();
double portX = port.getRotatedOffX();
return nodeX + portX;
}
/**
* Calculate the absolute position of a placementPort (y direction)
*
* @param port
* @return absolut y position
*/
private double getPlacementY(PlacementPort port) {
double nodeY = port.getPlacementNode().getPlacementY();
double portY = port.getRotatedOffY();
return nodeY + portY;
}
}