001 package aima.test.probreasoningtest;
002
003 import java.util.ArrayList;
004 import java.util.List;
005
006 import junit.framework.TestCase;
007 import aima.probability.RandomVariable;
008 import aima.probability.reasoning.FixedLagSmoothing;
009 import aima.probability.reasoning.HMMFactory;
010 import aima.probability.reasoning.HiddenMarkovModel;
011 import aima.probability.reasoning.HmmConstants;
012
013 /**
014 * @author Ravi Mohan
015 *
016 */
017 public class HMMTest extends TestCase {
018 private HiddenMarkovModel robotHmm, rainmanHmm;
019
020 private static final double TOLERANCE = 0.001;
021
022 @Override
023 public void setUp() {
024 robotHmm = HMMFactory.createRobotHMM();
025 rainmanHmm = HMMFactory.createRainmanHMM();
026 }
027
028 public void testRobotHMMInitialization() {
029
030 assertEquals(0.5, robotHmm.prior().getProbabilityOf(
031 HmmConstants.DOOR_OPEN));
032 assertEquals(0.5, robotHmm.prior().getProbabilityOf(
033 HmmConstants.DOOR_CLOSED));
034 }
035
036 public void testRainmanHmmInitialization() {
037
038 assertEquals(0.5, rainmanHmm.prior().getProbabilityOf(
039 HmmConstants.RAINING));
040 assertEquals(0.5, rainmanHmm.prior().getProbabilityOf(
041 HmmConstants.NOT_RAINING));
042 }
043
044 public void testForwardMessagingWorksForFiltering() {
045 RandomVariable afterOneStep = robotHmm.forward(robotHmm.prior(),
046 HmmConstants.DO_NOTHING, HmmConstants.SEE_DOOR_OPEN);
047 assertEquals(0.75, afterOneStep
048 .getProbabilityOf(HmmConstants.DOOR_OPEN), TOLERANCE);
049 assertEquals(0.25, afterOneStep
050 .getProbabilityOf(HmmConstants.DOOR_CLOSED), TOLERANCE);
051
052 RandomVariable afterTwoSteps = robotHmm.forward(afterOneStep,
053 HmmConstants.PUSH_DOOR, HmmConstants.SEE_DOOR_OPEN);
054 assertEquals(0.983, afterTwoSteps
055 .getProbabilityOf(HmmConstants.DOOR_OPEN), TOLERANCE);
056 assertEquals(0.017, afterTwoSteps
057 .getProbabilityOf(HmmConstants.DOOR_CLOSED), TOLERANCE);
058 }
059
060 public void testRecursiveBackwardMessageCalculationIsCorrect() {
061 RandomVariable afterOneStep = rainmanHmm.forward(rainmanHmm.prior(),
062 HmmConstants.DO_NOTHING, HmmConstants.SEE_UMBRELLA);
063 RandomVariable afterTwoSteps = rainmanHmm.forward(afterOneStep,
064 HmmConstants.DO_NOTHING, HmmConstants.SEE_UMBRELLA);
065
066 RandomVariable postSequence = afterTwoSteps.duplicate()
067 .createUnitBelief();
068
069 RandomVariable smoothed = rainmanHmm.calculate_next_backward_message(
070 afterOneStep, postSequence, HmmConstants.SEE_UMBRELLA);
071 assertEquals(0.883, smoothed.getProbabilityOf(HmmConstants.RAINING),
072 TOLERANCE);
073 assertEquals(0.117,
074 smoothed.getProbabilityOf(HmmConstants.NOT_RAINING), TOLERANCE);
075
076 }
077
078 public void testForwardBackwardOnRainmanHmm() {
079 List<String> perceptions = new ArrayList<String>();
080 perceptions.add(HmmConstants.SEE_UMBRELLA);
081 perceptions.add(HmmConstants.SEE_UMBRELLA);
082
083 List<RandomVariable> results = rainmanHmm.forward_backward(perceptions);
084 assertEquals(3, results.size());
085
086 assertNull(results.get(0));
087 RandomVariable smoothedDayOne = results.get(1);
088 assertEquals(0.982, smoothedDayOne
089 .getProbabilityOf(HmmConstants.RAINING), TOLERANCE);
090 assertEquals(0.018, smoothedDayOne
091 .getProbabilityOf(HmmConstants.NOT_RAINING), TOLERANCE);
092
093 RandomVariable smoothedDayTwo = results.get(2);
094 assertEquals(0.883, smoothedDayTwo
095 .getProbabilityOf(HmmConstants.RAINING), TOLERANCE);
096 assertEquals(0.117, smoothedDayTwo
097 .getProbabilityOf(HmmConstants.NOT_RAINING), TOLERANCE);
098
099 }
100
101 public void testForwardBackwardOnRainmanHmmFor3daysData() {
102 List<String> perceptions = new ArrayList<String>();
103 perceptions.add(HmmConstants.SEE_UMBRELLA);
104 perceptions.add(HmmConstants.SEE_UMBRELLA);
105 perceptions.add(HmmConstants.SEE_NO_UMBRELLA);
106
107 List<RandomVariable> results = rainmanHmm.forward_backward(perceptions);
108 assertEquals(4, results.size());
109 assertNull(results.get(0));
110
111 RandomVariable smoothedDayOne = results.get(1);
112 assertEquals(0.964, smoothedDayOne
113 .getProbabilityOf(HmmConstants.RAINING), TOLERANCE);
114 assertEquals(0.036, smoothedDayOne
115 .getProbabilityOf(HmmConstants.NOT_RAINING), TOLERANCE);
116
117 RandomVariable smoothedDayTwo = results.get(2);
118 assertEquals(0.484, smoothedDayTwo
119 .getProbabilityOf(HmmConstants.RAINING), TOLERANCE);
120 assertEquals(0.516, smoothedDayTwo
121 .getProbabilityOf(HmmConstants.NOT_RAINING), TOLERANCE);
122
123 RandomVariable smoothedDayThree = results.get(3);
124 assertEquals(0.190, smoothedDayThree
125 .getProbabilityOf(HmmConstants.RAINING), TOLERANCE);
126 assertEquals(0.810, smoothedDayThree
127 .getProbabilityOf(HmmConstants.NOT_RAINING), TOLERANCE);
128 }
129
130 public void xtestForwardBackwardAndFixedLagSmoothingGiveSameResults() {
131
132 // test disabled pending algorithm clarification
133 List<String> perceptions = new ArrayList<String>();
134
135 String dayOnePerception = HmmConstants.SEE_UMBRELLA;
136 String dayTwoPerception = HmmConstants.SEE_UMBRELLA;
137 String dayThreePerception = HmmConstants.SEE_NO_UMBRELLA;
138
139 perceptions.add(dayOnePerception);
140 perceptions.add(dayTwoPerception);
141 perceptions.add(dayThreePerception);
142
143 List<RandomVariable> fbResults = rainmanHmm
144 .forward_backward(perceptions);
145 assertEquals(4, fbResults.size());
146
147 RandomVariable fbDayOneResult = fbResults.get(1);
148 System.out.println(fbDayOneResult);
149
150 FixedLagSmoothing fls = new FixedLagSmoothing(rainmanHmm, 2);
151
152 assertNull(fls.smooth(dayOnePerception));
153 System.out.println(fls.smooth(dayTwoPerception));
154 RandomVariable flsDayoneResult = fls.smooth(dayThreePerception);
155 System.out.println(flsDayoneResult);
156
157 }
158
159 public void testOneStepFixedLagSmoothingOnRainManHmm() {
160 FixedLagSmoothing fls = new FixedLagSmoothing(rainmanHmm, 1);
161
162 RandomVariable smoothedDayZero = fls.smooth(HmmConstants.SEE_UMBRELLA); // see
163 // umbrella
164 // on
165 // day
166 // one
167 assertEquals(0.627, smoothedDayZero
168 .getProbabilityOf(HmmConstants.RAINING), TOLERANCE);
169
170 RandomVariable smoothedDayOne = fls.smooth(HmmConstants.SEE_UMBRELLA); // see
171 // umbrella
172 // on
173 // day
174 // two
175 assertEquals(0.883, smoothedDayOne
176 .getProbabilityOf(HmmConstants.RAINING), TOLERANCE);
177 assertEquals(0.117, smoothedDayOne
178 .getProbabilityOf(HmmConstants.NOT_RAINING), TOLERANCE);
179
180 RandomVariable smoothedDayTwo = fls
181 .smooth(HmmConstants.SEE_NO_UMBRELLA); // see no umbrella on
182 // day three
183 assertEquals(0.799, smoothedDayTwo
184 .getProbabilityOf(HmmConstants.RAINING), TOLERANCE);
185 assertEquals(0.201, smoothedDayTwo
186 .getProbabilityOf(HmmConstants.NOT_RAINING), TOLERANCE);
187 }
188
189 public void testOneStepFixedLagSmoothingOnRainManHmmWithDifferingEvidence() {
190 FixedLagSmoothing fls = new FixedLagSmoothing(rainmanHmm, 1);
191
192 RandomVariable smoothedDayZero = fls.smooth(HmmConstants.SEE_UMBRELLA);// see
193 // umbrella
194 // on
195 // day
196 // one
197 assertEquals(0.627, smoothedDayZero
198 .getProbabilityOf(HmmConstants.RAINING), TOLERANCE);
199
200 RandomVariable smoothedDayOne = fls
201 .smooth(HmmConstants.SEE_NO_UMBRELLA);// no umbrella on day
202 // two
203 assertEquals(0.702, smoothedDayOne
204 .getProbabilityOf(HmmConstants.RAINING), TOLERANCE);
205 assertEquals(0.297, smoothedDayOne
206 .getProbabilityOf(HmmConstants.NOT_RAINING), TOLERANCE);
207 }
208
209 public void testTwoStepFixedLagSmoothingOnRainManHmm() {
210 FixedLagSmoothing fls = new FixedLagSmoothing(rainmanHmm, 2);
211
212 RandomVariable smoothedOne = fls.smooth(HmmConstants.SEE_UMBRELLA); // see
213 // umbrella
214 // on
215 // day
216 // one
217 assertNull(smoothedOne);
218
219 smoothedOne = fls.smooth(HmmConstants.SEE_UMBRELLA); // see
220 // umbrella
221 // on
222 // day
223 // two
224 assertEquals(0.653, smoothedOne.getProbabilityOf(HmmConstants.RAINING),
225 TOLERANCE);
226 assertEquals(0.346, smoothedOne
227 .getProbabilityOf(HmmConstants.NOT_RAINING), TOLERANCE);
228
229 RandomVariable smoothedTwo = fls.smooth(HmmConstants.SEE_UMBRELLA);// see
230 // umbrella
231 // on
232 // day
233 // 3
234 assertEquals(0.894, smoothedTwo.getProbabilityOf(HmmConstants.RAINING),
235 TOLERANCE);
236 assertEquals(0.105, smoothedTwo
237 .getProbabilityOf(HmmConstants.NOT_RAINING), TOLERANCE);
238
239 }
240 }