BDDPairing.java

// BDDPairing.java, created Jan 29, 2003 9:50:57 PM by jwhaley
// Copyright (C) 2003 John Whaley
// Licensed under the terms of the GNU LGPL; see COPYING for details.
package net.sf.javabdd;

/**
 * Encodes a table of variable pairs.  This is used for replacing variables in a
 * BDD.
 * 
 * @author John Whaley
 * @version $Id: BDDPairing.java,v 1.1 2004/10/16 02:58:57 joewhaley Exp $
 */
public abstract class BDDPairing {

    /**
     * Adds the pair (oldvar, newvar) to this table of pairs. This results in
     * oldvar being substituted with newvar in a call to BDD.replace().
     * 
     * Compare to bdd_setpair.
     */
    public abstract void set(int oldvar, int newvar);

    /**
     * Like set(), but with a whole list of pairs.
     * 
     * Compare to bdd_setpairs.
     */
    public void set(int[] oldvar, int[] newvar) {
        if (oldvar.length != newvar.length)
            throw new BDDException();

        for (int n = 0; n < oldvar.length; n++)
            this.set(oldvar[n], newvar[n]);
    }
    
    /**
     * Adds the pair (oldvar, newvar) to this table of pairs. This results in
     * oldvar being substituted with newvar in a call to bdd.replace().  The
     * variable oldvar is substituted with the BDD newvar.  The possibility to
     * substitute with any BDD as newvar is utilized in BDD.compose(), whereas
     * only the topmost variable in the BDD is used in BDD.replace().
     * 
     * Compare to bdd_setbddpair.
     */
    public abstract void set(int oldvar, BDD newvar);

    /**
     * Like set(), but with a whole list of pairs.
     * 
     * Compare to bdd_setbddpairs.
     */
    public void set(int[] oldvar, BDD[] newvar) {
        if (oldvar.length != newvar.length)
            throw new BDDException();

        for (int n = 0; n < newvar.length; n++)
            this.set(oldvar[n], newvar[n]);
    }
    
    /**
     * Defines each variable in the finite domain block p1 to be paired with the
     * corresponding variable in p2.
     * 
     * Compare to fdd_setpair.
     */
    public void set(BDDDomain p1, BDDDomain p2) {
        int[] ivar1 = p1.vars();
        int[] ivar2 = p2.vars();
        this.set(ivar1, ivar2);
    }

    /**
     * Like set(), but with a whole list of pairs.
     * 
     * Compare to fdd_setpairs.
     */
    public void set(BDDDomain[] p1, BDDDomain[] p2) {
        if (p1.length != p2.length)
            throw new BDDException();

        for (int n = 0; n < p1.length; n++)
            if (p1[n].varNum() != p2[n].varNum())
                throw new BDDException();

        for (int n = 0; n < p1.length; n++) {
            this.set(p1[n], p2[n]);
        }
    }

    /**
     * Resets this table of pairs by setting all substitutions to their default
     * values (that is, no change).
     * 
     * Compare to bdd_resetpair.
     */
    public abstract void reset();

}