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Diffstat (limited to 'elki/src/test/java/de/lmu/ifi/dbs/elki/utilities/datastructures/arrays/IntegerArrayQuickSortTest.java')
| -rw-r--r-- | elki/src/test/java/de/lmu/ifi/dbs/elki/utilities/datastructures/arrays/IntegerArrayQuickSortTest.java | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/elki/src/test/java/de/lmu/ifi/dbs/elki/utilities/datastructures/arrays/IntegerArrayQuickSortTest.java b/elki/src/test/java/de/lmu/ifi/dbs/elki/utilities/datastructures/arrays/IntegerArrayQuickSortTest.java new file mode 100644 index 00000000..0e5ee922 --- /dev/null +++ b/elki/src/test/java/de/lmu/ifi/dbs/elki/utilities/datastructures/arrays/IntegerArrayQuickSortTest.java @@ -0,0 +1,136 @@ +package de.lmu.ifi.dbs.elki.utilities.datastructures.arrays; + +/* + This file is part of ELKI: + Environment for Developing KDD-Applications Supported by Index-Structures + + Copyright (C) 2015 + 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.assertTrue; + +import java.util.Random; + +import org.junit.Test; + +import de.lmu.ifi.dbs.elki.JUnit4Test; + +/** + * Test the integer array (index array) quick sort. + * + * @author Erich Schubert + * @since 0.7.0 + */ +public class IntegerArrayQuickSortTest implements JUnit4Test { + /** + * Array size to use. + */ + final int SIZE = 10000; + + @Test + public void testRandomDoubles() { + for(int i = 1; i < 10; i++) { + testQuickSort(i); + } + testQuickSort(SIZE); + testQuickSort(SIZE + 1); + } + + private void testQuickSort(int size) { + final double[] data = new double[size]; + int[] idx = new int[size]; + + // Make a random generator, but remember the seed for debugging. + Random r = new Random(); + long seed = r.nextLong(); + r = new Random(seed); + + // Produce data + for(int i = 0; i < size; i++) { + data[i] = r.nextDouble(); + idx[i] = i; + } + + // Run QuickSort and validate monotonicity. + IntegerArrayQuickSort.sort(idx, new IntegerComparator() { + @Override + public int compare(int x, int y) { + return Double.compare(data[x], data[y]); + } + }); + double prev = data[idx[0]]; + for(int i = 1; i < size; i++) { + double val = data[idx[i]]; + assertTrue("Resulting array is not sorted. Seed=" + seed, prev <= val); + prev = val; + } + } + + @Test(timeout = 500) + public void testTies() { + int size = 1000000; + int[] idx = new int[size]; + + // Initialize indexes + for(int i = 0; i < size; i++) { + idx[i] = 0; + } + + // Run QuickSort and validate monotonicity. + IntegerArrayQuickSort.sort(idx, new IntegerComparator() { + @Override + public int compare(int x, int y) { + return (x < y) ? -1 : (x == y) ? 0 : +1; + } + }); + + int prev = idx[0]; + for(int i = 1; i < size; i++) { + int val = idx[i]; + assertTrue("Resulting array is not sorted.", prev <= val); + prev = val; + } + } + + @Test(timeout = 500) + public void testSorted() { + int size = 1000000; + int[] idx = new int[size]; + + // Initialize indexes + for(int i = 0; i < size; i++) { + idx[i] = size - i; + } + + // Run QuickSort and validate monotonicity. + IntegerArrayQuickSort.sort(idx, new IntegerComparator() { + @Override + public int compare(int x, int y) { + return (x < y) ? -1 : (x == y) ? 0 : +1; + } + }); + + int prev = idx[0]; + for(int i = 1; i < size; i++) { + int val = idx[i]; + assertTrue("Resulting array is not sorted.", prev <= val); + prev = val; + } + } +}
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