Lucas Dupin | 1d3c00d5 | 2017-06-05 08:40:39 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2017 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.android.internal.ml.clustering; |
| 18 | |
| 19 | import static org.junit.Assert.assertEquals; |
| 20 | import static org.junit.Assert.assertTrue; |
| 21 | |
| 22 | import android.annotation.SuppressLint; |
| 23 | import android.support.test.filters.SmallTest; |
| 24 | import android.support.test.runner.AndroidJUnit4; |
| 25 | |
| 26 | import org.junit.Assert; |
| 27 | import org.junit.Before; |
| 28 | import org.junit.Test; |
| 29 | import org.junit.runner.RunWith; |
| 30 | |
| 31 | import java.util.Arrays; |
| 32 | import java.util.List; |
| 33 | import java.util.Random; |
| 34 | |
| 35 | @SmallTest |
| 36 | @RunWith(AndroidJUnit4.class) |
| 37 | public class KMeansTest { |
| 38 | |
| 39 | // Error tolerance (epsilon) |
| 40 | private static final double EPS = 0.01; |
| 41 | |
| 42 | private KMeans mKMeans; |
| 43 | |
| 44 | @Before |
| 45 | public void setUp() { |
| 46 | // Setup with a random seed to have predictable results |
| 47 | mKMeans = new KMeans(new Random(0), 30, 0); |
| 48 | } |
| 49 | |
| 50 | @Test |
| 51 | public void getCheckDataSanityTest() { |
| 52 | try { |
| 53 | mKMeans.checkDataSetSanity(new float[][] { |
| 54 | {0, 1, 2}, |
| 55 | {1, 2, 3} |
| 56 | }); |
| 57 | } catch (IllegalArgumentException e) { |
| 58 | Assert.fail("Valid data didn't pass sanity check"); |
| 59 | } |
| 60 | |
| 61 | try { |
| 62 | mKMeans.checkDataSetSanity(new float[][] { |
| 63 | null, |
| 64 | {1, 2, 3} |
| 65 | }); |
| 66 | Assert.fail("Data has null items and passed"); |
| 67 | } catch (IllegalArgumentException e) {} |
| 68 | |
| 69 | try { |
| 70 | mKMeans.checkDataSetSanity(new float[][] { |
| 71 | {0, 1, 2, 4}, |
| 72 | {1, 2, 3} |
| 73 | }); |
| 74 | Assert.fail("Data has invalid shape and passed"); |
| 75 | } catch (IllegalArgumentException e) {} |
| 76 | |
| 77 | try { |
| 78 | mKMeans.checkDataSetSanity(null); |
| 79 | Assert.fail("Null data should throw exception"); |
| 80 | } catch (IllegalArgumentException e) {} |
| 81 | } |
| 82 | |
| 83 | @Test |
| 84 | public void sqDistanceTest() { |
| 85 | float a[] = {4, 10}; |
| 86 | float b[] = {5, 2}; |
| 87 | float sqDist = (float) (Math.pow(a[0] - b[0], 2) + Math.pow(a[1] - b[1], 2)); |
| 88 | |
| 89 | assertEquals("Squared distance not valid", mKMeans.sqDistance(a, b), sqDist, EPS); |
| 90 | } |
| 91 | |
| 92 | @Test |
| 93 | public void nearestMeanTest() { |
| 94 | KMeans.Mean meanA = new KMeans.Mean(0, 1); |
| 95 | KMeans.Mean meanB = new KMeans.Mean(1, 1); |
| 96 | List<KMeans.Mean> means = Arrays.asList(meanA, meanB); |
| 97 | |
| 98 | KMeans.Mean nearest = mKMeans.nearestMean(new float[] {1, 1}, means); |
| 99 | |
| 100 | assertEquals("Unexpected nearest mean for point {1, 1}", nearest, meanB); |
| 101 | } |
| 102 | |
| 103 | @SuppressLint("DefaultLocale") |
| 104 | @Test |
| 105 | public void scoreTest() { |
| 106 | List<KMeans.Mean> closeMeans = Arrays.asList(new KMeans.Mean(0, 0.1f, 0.1f), |
| 107 | new KMeans.Mean(0, 0.1f, 0.15f), |
| 108 | new KMeans.Mean(0.1f, 0.2f, 0.1f)); |
| 109 | List<KMeans.Mean> farMeans = Arrays.asList(new KMeans.Mean(0, 0, 0), |
| 110 | new KMeans.Mean(0, 0.5f, 0.5f), |
| 111 | new KMeans.Mean(1, 0.9f, 0.9f)); |
| 112 | |
| 113 | double closeScore = KMeans.score(closeMeans); |
| 114 | double farScore = KMeans.score(farMeans); |
| 115 | assertTrue(String.format("Score of well distributed means should be greater than " |
| 116 | + "close means but got: %f, %f", farScore, closeScore), farScore > closeScore); |
| 117 | } |
| 118 | |
| 119 | @Test |
| 120 | public void predictTest() { |
| 121 | float[] expectedCentroid1 = {1, 1, 1}; |
| 122 | float[] expectedCentroid2 = {0, 0, 0}; |
| 123 | float[][] X = new float[][] { |
| 124 | {1, 1, 1}, |
| 125 | {1, 1, 1}, |
| 126 | {1, 1, 1}, |
| 127 | {0, 0, 0}, |
| 128 | {0, 0, 0}, |
| 129 | {0, 0, 0}, |
| 130 | }; |
| 131 | |
| 132 | final int numClusters = 2; |
| 133 | |
| 134 | // Here we assume that we won't get stuck into a local optima. |
| 135 | // It's fine because we're seeding a random, we won't ever have |
| 136 | // unstable results but in real life we need multiple initialization |
| 137 | // and score comparison |
| 138 | List<KMeans.Mean> means = mKMeans.predict(numClusters, X); |
| 139 | |
| 140 | assertEquals("Expected number of clusters is invalid", numClusters, means.size()); |
| 141 | |
| 142 | boolean exists1 = false, exists2 = false; |
| 143 | for (KMeans.Mean mean : means) { |
| 144 | if (Arrays.equals(mean.getCentroid(), expectedCentroid1)) { |
| 145 | exists1 = true; |
| 146 | } else if (Arrays.equals(mean.getCentroid(), expectedCentroid2)) { |
| 147 | exists2 = true; |
| 148 | } else { |
| 149 | throw new AssertionError("Unexpected mean: " + mean); |
| 150 | } |
| 151 | } |
| 152 | assertTrue("Expected means were not predicted, got: " + means, |
| 153 | exists1 && exists2); |
| 154 | } |
| 155 | } |