/*______________________________________________________________________________
*
* Copyright 2005 Arnaud Bailly - NORSYS/LIFL
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* (1) Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* (2) Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* (3) The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Created on 10 mai 2005
*
*/
package rationals.algebra;
import java.util.Iterator;
import java.util.Set;
import rationals.Rational;
import rationals.State;
import rationals.Transition;
import rationals.expr.Letter;
import rationals.expr.Plus;
import rationals.expr.RationalExpr;
/**
* A matrix for representing regular languages.
* <p>
* The cell of the matrix are rational expressions made from concatenation,
* epsilon, letters and union.
*
* @author nono
* @version $Id: RationalMatrix.java 2 2006-08-24 14:41:48Z oqube $
* @see rationals.expr
*/
public class RationalMatrix {
private Matrix init;
private Matrix fini;
private Matrix transitions;
/**
* @return Returns the fini.
*/
public Matrix getFini() {
return fini;
}
/**
* @param fini The fini to set.
*/
public void setFini(Matrix fini) {
this.fini = fini;
}
/**
* @return Returns the init.
*/
public Matrix getInit() {
return init;
}
/**
* @param init The init to set.
*/
public void setInit(Matrix init) {
this.init = init;
}
/**
* @return Returns the transitions.
*/
public Matrix getTransitions() {
return transitions;
}
/**
* @param transitions The transitions to set.
*/
public void setTransitions(Matrix transitions) {
this.transitions = transitions;
}
/**
* Construct the matrix of a rational language.
*
* @param rat
* a Rational language.
*/
public RationalMatrix(Rational rat) {
Set st = rat.states();
int n = st.size();
init = Matrix.zero(1,n,RationalExpr.zero);
fini = Matrix.zero(n,1,RationalExpr.zero);
transitions = Matrix.zero(n,n,RationalExpr.zero);
State[] sta = (State[]) rat.states().toArray(new State[n]);
/* fill matrices */
for (int i = 0; i < sta.length; i++) {
if (sta[i].isInitial())
init.matrix[0][i] = Letter.epsilon;
else
init.matrix[0][i] = RationalExpr.zero;
if (sta[i].isTerminal())
fini.matrix[i][0] = Letter.epsilon;
else
fini.matrix[i][0] = RationalExpr.zero;
/* transitions */
for (int j = 0; j < n; j++) {
Set trs = rat.deltaFrom(sta[i], (State) sta[j]);
RationalExpr re = null;
for (Iterator it = trs.iterator(); it.hasNext();) {
Transition tr = (Transition) it.next();
Object o = tr.label();
Letter l = (o == null) ? Letter.epsilon : new Letter(o);
if (re == null)
re = l;
else
re = new Plus(re, l);
}
transitions.matrix[i][j] = re == null ? RationalExpr.zero : re;
}
}
}
/**
* Compute words from this rational whose length is
* n.
*
* @param n
* @return
*/
public Matrix nwords(int n) {
Matrix res = transitions.power(n,Matrix.zero(transitions.getLine(),transitions.getLine(),RationalExpr.zero));
/* compute product for init and fini */
Matrix in = (Matrix)init.mult(res);
return (Matrix)in.mult(fini);
}
public String toString() {
return init.toString() + '\n'+ transitions.toString() + '\n'+fini.toString();
}
}