/**Copyright or (C) or Copr. GET / ENST, Telecom-Paris, Ludovic Apvrille
ludovic.apvrille AT enst.fr
This software is a computer program whose purpose is to allow the
edition of TURTLE analysis, design and deployment diagrams, to
allow the generation of RT-LOTOS or Java code from this diagram,
and at last to allow the analysis of formal validation traces
obtained from external tools, e.g. RTL from LAAS-CNRS and CADP
from INRIA Rhone-Alpes.
This software is governed by the CeCILL license under French law and
abiding by the rules of distribution of free software. You can use,
modify and/ or redistribute the software under the terms of the CeCILL
license as circulated by CEA, CNRS and INRIA at the following URL
"http://www.cecill.info".
As a counterpart to the access to the source code and rights to copy,
modify and redistribute granted by the license, users are provided only
with a limited warranty and the software's author, the holder of the
economic rights, and the successive licensors have only limited
liability.
In this respect, the user's attention is drawn to the risks associated
with loading, using, modifying and/or developing or reproducing the
software by the user in light of its specific status of free software,
that may mean that it is complicated to manipulate, and that also
therefore means that it is reserved for developers and experienced
professionals having in-depth computer knowledge. Users are therefore
encouraged to load and test the software's suitability as regards their
requirements in conditions enabling the security of their systems and/or
data to be ensured and, more generally, to use and operate it in the
same conditions as regards security.
The fact that you are presently reading this means that you have had
knowledge of the CeCILL license and that you accept its terms.
/**
* Class GraphAlgorithms
*
* Creation: 16/09/2004
* @version 1.0 16/09/2004
* @author Ludovic APVRILLE
* @see
*/
package myutil;
import java.util.ArrayList;
public class GraphAlgorithms {
public static boolean go = true;
// Assume that states are numbered from 0 to nbState - 1
public static boolean hasCycle(Graph g){
int nbState = g.getNbOfStates();
int i,j;
if (nbState == 0) {
return false;
}
TraceManager.addDev("cycle0? Nb state = " + nbState + "\n");
DijkstraState[] states = new DijkstraState[nbState];
for(i=0; i<nbState; i++) {
states[i] = new DijkstraState(i);
states[i].previous = -1;
states[i].used = false;
states[i].weight = 0;
}
if (go == false) {
return false;
}
TraceManager.addDev("cycle1? Nb state = " + nbState + "\n");
// Succ
int succ;
for(i=0; i<nbState; i++) {
/*if ((i % 100) == 0) {
System.out.println("i=" + i);
}*/
for(j=0; j<nbState; j++) {
succ = g.getWeightOfTransition(i, j);
if (succ > 0) {
states[j].weight ++;
}
}
}
if (go == false) {
return false;
}
int nb = 0;
ArrayList<Integer> list = new ArrayList<Integer>();
TraceManager.addDev("cycle2? Nb state = " + nbState+ "\n");
for(i=0; i<nbState; i++) {
if (states[i].weight == 0) {
list.add(new Integer(i));
nb ++;
}
}
TraceManager.addDev("cycle3? Nb state = " + nbState + " nb=" + nb + "\n");
int index;
while((list.size() > 0) && (go == true)){
index = list.get(0).intValue();
list.remove(0);
for(j=0; j<nbState; j++) {
succ = g.getWeightOfTransition(index, j);
if (succ > 0) {
states[j].weight --;
if (states[j].weight == 0) {
list.add(new Integer(j));
nb ++;
}
}
}
}
TraceManager.addDev("cycle4? Nb state = " + nbState + " nb=" + nb + "\n");
return !(nb == nbState);
}
public static DijkstraState[] ShortestPathFrom(Graph g, int startState){
int nbState = g.getNbOfStates();
if (nbState == 0) {
return null;
}
//System.out.println("Nb state = " + nbState + " startState = " + startState);
DijkstraState[] states = new DijkstraState[nbState];
int i;
/* init of states */
for(i=0; i<nbState; i++) {
states[i] = new DijkstraState(i);
states[i].previous = -1;
states[i].used = false;
states[i].weight = Integer.MAX_VALUE;
}
states[startState].used = false;
states[startState].weight = 0;
states[startState].previous = -1;
if (go == true) {
iterativeShortestPathFrom(g, states, startState);
}
if (go == true) {
computePaths(states, startState);
}
if (go == false) {
//System.out.println("Algorithm stopped");
return null;
}
return states;
}
public static void iterativeShortestPathFrom(Graph g, DijkstraState[] states, int startState) {
//DijkstraState ds;
int weight;
//int[] path;
int currentState;
while (((currentState = getNextStateToCompute(states, startState)) != -1) && (go == true)) {
//System.out.println("State managed:" + currentState);
states[currentState].used = true;
for(int i=0; (i<states.length) && (go == true); i++) {
weight = g.getWeightOfTransition(currentState, i);
// adjacent state
if (weight > 0) {
if (!states[i].used) {
if((states[currentState].weight + weight) < states[i].weight) {
states[i].weight = states[currentState].weight + weight;
states[i].previous = currentState;
}
}
}
}
if (go == false) {
return;
}
}
}
private static int getNextStateToCompute(DijkstraState[] states, int startState) {
int minWeight = Integer.MAX_VALUE;
int state = -1;
for(int i=0; i<states.length; i++) {
if (go == false) {
return 0;
}
if ((!states[i].used) && (states[i].weight <= minWeight)) {
state = i;
minWeight = states[i].weight;
//System.out.println("MinWeight = " + minWeight + " state=" + i);
}
}
return state;
}
// Assumes no cycle!
public static DijkstraState[] LongestPathFrom(Graph g, int startState){
//System.out.println("Cycle detection");
/*boolean result = hasCycle(g);
if (result) {
System.out.println("The graph contains cycles");
return null;
} else {
System.out.println("The graph has no cycle");
}*/
int nbState = g.getNbOfStates();
if (nbState == 0) {
return null;
}
//System.out.println("Longest path Nb state = " + nbState + " startState = " + startState);
DijkstraState[] states = new DijkstraState[nbState];
int i;
/* init of states */
for(i=0; i<nbState; i++) {
states[i] = new DijkstraState(i);
states[i].previous = -1;
states[i].used = false;
states[i].weight = -1;
}
states[startState].used = false;
states[startState].weight = 0;
states[startState].previous = -1;
if (go == true) {
iterativeLongestPathFrom(g, states, startState);
}
if (go == true) {
computePaths(states, startState);
}
if (go == false) {
//System.out.println("Algorithm stopped");
return null;
}
return states;
}
public static void iterativeLongestPathFrom(Graph g, DijkstraState[] states, int startState) {
//DijkstraState ds;
int weight;
//int[] path;
int currentState;
int tmp;
while (((currentState = getNextLongestStateToCompute(states, startState)) != -1) && (go == true)) {
//System.out.println("State managed:" + currentState + " weight=" + states[currentState].weight);
states[currentState].used = true;
for(int i=0; (i<states.length) && (go == true); i++) {
weight = g.getWeightOfTransition(currentState, i);
// adjacent state
if (weight > 0) {
//if (!states[i].used) {
if(states[currentState].weight + weight > states[i].weight) {
tmp = states[i].weight;
//if (!states[i].used) {
states[i].weight = states[currentState].weight + weight;
states[i].previous = currentState;
states[i].used = false;
//System.out.println("Changing weight of state " + i + " former=" + tmp + " new=" +states[i].weight);
//}
}
//}
}
}
if (go == false) {
return;
}
}
}
private static int getNextLongestStateToCompute(DijkstraState[] states, int startState) {
int maxWeight = -2;
int state = -1;
for(int i=0; i<states.length; i++) {
if (go == false) {
return 0;
}
if ((!states[i].used) && (states[i].weight > maxWeight)) {
state = i;
maxWeight = states[i].weight;
//System.out.println("MaxWeight = " + maxWeight + " state=" + i);
}
}
return state;
}
private static void computePaths(DijkstraState[] states, int startState) {
int size;
int [] path;
for(int i=0; (i<states.length) && (go == true); i++) {
size = computePathLength(states, i, startState);
//System.out.println("i = " + i + " size=" + size);
if (size ==0) {
states[i].path = new int[0];
} else {
path = new int[size+1];
states[i].path = path;
makePath(states, i, path, path.length - 1);
}
}
}
private static int computePathLength(DijkstraState[] states, int state, int startState) {
//System.out.println("Compute path, state = " + state);
if (go == false) {
return 0;
}
if (state == startState) {
return 0;
}
if (states[state].previous == -1) {
return -1;
} else {
int ret = computePathLength(states, states[state].previous, startState);
if (ret == -1)
return -1;
else
return 1 + ret;
}
}
private static void makePath(DijkstraState[] states, int state, int [] path, int index) {
while(index>=0) {
path[index] = state;
index --;
state = states[state].previous;
}
}
}