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Diffstat (limited to 'test/de/lmu/ifi/dbs/elki/utilities/datastructures/heap/TestHeapPerformance.java')
| -rw-r--r-- | test/de/lmu/ifi/dbs/elki/utilities/datastructures/heap/TestHeapPerformance.java | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/test/de/lmu/ifi/dbs/elki/utilities/datastructures/heap/TestHeapPerformance.java b/test/de/lmu/ifi/dbs/elki/utilities/datastructures/heap/TestHeapPerformance.java new file mode 100644 index 00000000..2f990e30 --- /dev/null +++ b/test/de/lmu/ifi/dbs/elki/utilities/datastructures/heap/TestHeapPerformance.java @@ -0,0 +1,113 @@ +package de.lmu.ifi.dbs.elki.utilities.datastructures.heap; + +/* + This file is part of ELKI: + Environment for Developing KDD-Applications Supported by Index-Structures + + Copyright (C) 2012 + Ludwig-Maximilians-Universität München + Lehr- und Forschungseinheit für Datenbanksysteme + ELKI Development Team + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU Affero General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Affero General Public License for more details. + + You should have received a copy of the GNU Affero General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +import static org.junit.Assert.assertEquals; +import static org.junit.Assert.assertTrue; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; +import java.util.PriorityQueue; +import java.util.Queue; +import java.util.Random; + +import org.junit.Test; + +import de.lmu.ifi.dbs.elki.JUnit4Test; +import de.lmu.ifi.dbs.elki.utilities.datastructures.heap.Heap; + +/** + * Unit test to ensure that our heap is not significantly worse than SUN javas + * regular PriorityQueue. + * + * @author Erich Schubert + */ +public class TestHeapPerformance implements JUnit4Test { + final private int queueSize = 100000; + + final private int iterations = 20; + + final private long seed = 123456L; + + @Test + public void testRuntime() throws Exception { + // prepare the data set + final List<Integer> elements = new ArrayList<Integer>(queueSize); + { + final Random random = new Random(seed); + for(int i = 0; i < queueSize; i++) { + elements.add(i); + } + Collections.shuffle(elements, random); + } + + // Pretest, to trigger hotspot compiler, hopefully. + { + for(int j = 0; j < iterations; j++) { + Heap<Integer> pq = new Heap<Integer>(); + testQueue(elements, pq); + } + for(int j = 0; j < iterations; j++) { + PriorityQueue<Integer> pq = new PriorityQueue<Integer>(); // 11, + testQueue(elements, pq); + } + } + + long hstart = System.nanoTime(); + { + for(int j = 0; j < iterations; j++) { + Heap<Integer> pq = new Heap<Integer>(); + testQueue(elements, pq); + } + } + long htime = System.nanoTime() - hstart; + + long pqstart = System.nanoTime(); + { + for(int j = 0; j < iterations; j++) { + PriorityQueue<Integer> pq = new PriorityQueue<Integer>(); // 11 + testQueue(elements, pq); + } + } + long pqtime = System.nanoTime() - pqstart; + System.err.println("Heap performance test: us: " + htime*1E-9 + " java: " + pqtime*1E-9); + assertTrue("Heap performance regression - run test individually, since the hotspot optimizations may make the difference! " + htime + " >>= " + pqtime, htime < 1.05 * pqtime); + // 1.05 allows some difference in measuring + } + + private void testQueue(final List<Integer> elements, Queue<Integer> pq) { + // Insert all + for(int i = 0; i < elements.size(); i++) { + pq.add(elements.get(i)); + } + // Poll first half. + for(int i = 0; i < elements.size() >> 1; i++) { + assertEquals((int) pq.poll(), i); + // assertEquals((int) pq.poll(), queueSize - 1 - i); + } + assertTrue("Heap not half-empty?", pq.size() == (elements.size() >> 1)); + pq.clear(); + } +}
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