01: package org.mandarax.reference;
02:
03: /*
04: * Copyright (C) 1999-2004 <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</a>
05: *
06: * This library is free software; you can redistribute it and/or
07: * modify it under the terms of the GNU Lesser General Public
08: * License as published by the Free Software Foundation; either
09: * version 2 of the License, or (at your option) any later version.
10: *
11: * This library is distributed in the hope that it will be useful,
12: * but WITHOUT ANY WARRANTY; without even the implied warranty of
13: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14: * Lesser General Public License for more details.
15: *
16: * You should have received a copy of the GNU Lesser General Public
17: * License along with this library; if not, write to the Free Software
18: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19: */
20: import org.mandarax.kernel.Clause;
21: import org.mandarax.kernel.SelectionPolicy;
22:
23: /**
24: * Simple selection policy - just use the converse order of the
25: * negative literals of the goal.
26: * @author <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</A>
27: * @version 3.4 <7 March 05>
28: * @since 1.1
29: */
30: public final class RightMostSelectionPolicy implements SelectionPolicy {
31:
32: /**
33: * Return an array of integers specifying in which order the inference engine
34: * should attempt to unify the literals with the candidate.
35: * @return int[] the indices
36: * @param goal the goal
37: * @param appliedClause the clause that should be used to prove the goal
38: */
39: public int[] getOrderedPositions(Clause goal, Clause appliedClause) {
40: int l = goal.getNegativeLiterals().size();
41: int[] positions = new int[l];
42:
43: for (int i = 0; i < l; i++) {
44: positions[l - (i + 1)] = i;
45: }
46:
47: return positions;
48: }
49: }
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