/**
* Copyright 2013-2015 Pierre Merienne
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.github.pmerienne.trident.ml.stats;
import static org.junit.Assert.assertEquals;
import java.util.Random;
import org.junit.Test;
import com.github.pmerienne.trident.ml.stats.FixedStreamFeatureStatistics;
public class FixedStreamFeatureStatisticsTest {
@Test
public void testUpdate() {
// Given
Random random = new Random();
double expectedMean = 4.0;
double stdDev = 6.0;
int size = 10000;
double[] features = new double[size];
for (int i = 0; i < size; i++) {
features[i] = expectedMean + random.nextGaussian() * stdDev;
}
// When
FixedStreamFeatureStatistics statistics = new FixedStreamFeatureStatistics();
for (int i = 0; i < size; i++) {
statistics.update(features[i]);
}
// Then
assertEquals(expectedMean, statistics.getMean(), 0.1);
assertEquals(stdDev, statistics.getStdDev(), 0.1);
}
}