content: /**
   * Copyright (c) 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 static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  import at.ac.tuwien.kr.alpha.core.common.AtomStore;
  import at.ac.tuwien.kr.alpha.core.common.AtomStoreImpl;
  import at.ac.tuwien.kr.alpha.core.common.NoGood;
  import at.ac.tuwien.kr.alpha.core.programs.atoms.Literals;
  import at.ac.tuwien.kr.alpha.core.solver.ChoiceManager;
  import at.ac.tuwien.kr.alpha.core.solver.NoGoodStoreAlphaRoaming;
  import at.ac.tuwien.kr.alpha.core.solver.TrailAssignment;
  import at.ac.tuwien.kr.alpha.core.solver.WritableAssignment;
  
  /**
   * Tests {@link HeapOfActiveAtoms}, including initial heuristic scores computed by {@link MOMs}.
   *
   */
  public class HeapOfActiveAtomsTest {
  
  	private static final double DOUBLE_COMPARISON_EPSILON = 0.001;
  
  	private AtomStore atomStore;
  	private WritableAssignment assignment;
  	private VSIDS vsids;
  	private NoGoodStoreAlphaRoaming noGoodStore;
  
  	@BeforeEach
  	public void setUp() {
  		atomStore = new AtomStoreImpl();
  		assignment = new TrailAssignment(atomStore);
  		noGoodStore = new NoGoodStoreAlphaRoaming(assignment);
  		ChoiceManager choiceManager = new PseudoChoiceManager(assignment, noGoodStore);
  		this.vsids = new VSIDS(assignment, choiceManager, MOMs.DEFAULT_STRATEGY);
  	}
  
  	@Test
  	public void testAllAtomsEqualScore() {
  		int lit1 = Literals.atomToLiteral(1);
  		int lit2 = Literals.atomToLiteral(2);
  		int lit3 = Literals.atomToLiteral(3);
  		HeuristicTestUtils.addNoGoods(atomStore, assignment, noGoodStore, vsids, new NoGood(lit1, lit2), new NoGood(lit2, lit3),
  				new NoGood(lit1, lit3));
  		double activity1 = vsids.heapOfActiveAtoms.getActivity(lit1);
  		double activity2 = vsids.heapOfActiveAtoms.getActivity(lit2);
  		double activity3 = vsids.heapOfActiveAtoms.getActivity(lit3);
  		assertEquals(activity1, activity2, DOUBLE_COMPARISON_EPSILON);
  		assertEquals(activity2, activity3, DOUBLE_COMPARISON_EPSILON);
  	}
  
  	@Test
  	public void testOneAtomHigherScore() {
  		int lit1 = Literals.atomToLiteral(1);
  		int lit2 = Literals.atomToLiteral(2);
  		int lit3 = Literals.atomToLiteral(3);
  		int lit1Neg = Literals.atomToLiteral(1, false);
  		int lit2Neg = Literals.atomToLiteral(2, false);
  		int lit3Neg = Literals.atomToLiteral(3, false);
  		HeuristicTestUtils.addNoGoods(atomStore, assignment, noGoodStore, vsids, new NoGood(lit1, lit2Neg), new NoGood(lit1Neg, lit2),
  				new NoGood(lit2, lit3Neg), new NoGood(lit2Neg, lit3));
  		double activity1 = vsids.heapOfActiveAtoms.getActivity(lit1);
  		double activity2 = vsids.heapOfActiveAtoms.getActivity(lit2);
  		double activity3 = vsids.heapOfActiveAtoms.getActivity(lit3);
  		assertLessThan(activity1, activity2);
  		assertLessThan(activity3, activity2);
  	}
  
  	private static void assertLessThan(double d1, double d2) {
  		assertTrue(d1 < d2 + DOUBLE_COMPARISON_EPSILON);
  	}
  
  }
  