content: /**
   * Copyright (c) 2016, 2018-2019 Siemens AG
   * All rights reserved.
   * 
   * 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.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT HOLDER OR CONTRIBUTORS 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.
   */
  package at.ac.tuwien.kr.alpha.core.solver.heuristics;
  
  import at.ac.tuwien.kr.alpha.core.common.NoGood;
  import at.ac.tuwien.kr.alpha.core.solver.learning.GroundConflictNoGoodLearner;
  
  import static at.ac.tuwien.kr.alpha.core.programs.atoms.Literals.atomToLiteral;
  
  import java.util.Collection;
  
  /**
   * A heuristic that selects an atom to choose on.
   * 
   * Copyright (c) 2016, 2018 Siemens AG
   *
   */
  public interface BranchingHeuristic {
  	int DEFAULT_CHOICE_ATOM = 0;
  	int DEFAULT_CHOICE_LITERAL = atomToLiteral(DEFAULT_CHOICE_ATOM);
  
  	/**
  	 * Stores a newly violated {@link NoGood} and updates associated activity and sign counters.
  	 * 
  	 * @param violatedNoGood
  	 */
  	void violatedNoGood(NoGood violatedNoGood);
  
  	/**
  	 * Processes the result of a conflict analysis, i.e. counts literals in
  	 * {@link NoGood}s responsible for the conflict and stores a newly learned
  	 * {@link NoGood}.
  	 * 
  	 * @param analysisResult
  	 */
  	void analyzedConflict(GroundConflictNoGoodLearner.ConflictAnalysisResult analysisResult);
  
  	/**
  	 * Stores a newly grounded {@link NoGood} and updates associated activity counters.
  	 * 
  	 * @param newNoGood
  	 */
  	void newNoGood(NoGood newNoGood);
  	
  	/**
  	 * @see #newNoGood(NoGood)
  	 */
  	default void newNoGoods(Collection<NoGood> newNoGoods) {
  		newNoGoods.forEach(this::newNoGood);
  	}
  	
  	/**
  	 * Determines a literal (= atom + sign) to choose.
  	 *
  	 * @return the literal to choose, or {@link BranchingHeuristic#DEFAULT_CHOICE_LITERAL} if no such atom can be determined.
  	 */
  	int chooseLiteral();
  
  	default void growForMaxAtomId(int maxAtomId) {
  	}
  }
  