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Diffstat (limited to 'src/main/java/org/apache/commons/math3/stat/descriptive/rank/Median.java')
-rw-r--r-- | src/main/java/org/apache/commons/math3/stat/descriptive/rank/Median.java | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math3/stat/descriptive/rank/Median.java b/src/main/java/org/apache/commons/math3/stat/descriptive/rank/Median.java new file mode 100644 index 0000000..6350a0b --- /dev/null +++ b/src/main/java/org/apache/commons/math3/stat/descriptive/rank/Median.java @@ -0,0 +1,97 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 org.apache.commons.math3.stat.descriptive.rank; + +import java.io.Serializable; + +import org.apache.commons.math3.exception.MathIllegalArgumentException; +import org.apache.commons.math3.exception.NullArgumentException; +import org.apache.commons.math3.stat.ranking.NaNStrategy; +import org.apache.commons.math3.util.KthSelector; + + +/** + * Returns the median of the available values. This is the same as the 50th percentile. + * See {@link Percentile} for a description of the algorithm used. + * <p> + * <strong>Note that this implementation is not synchronized.</strong> If + * multiple threads access an instance of this class concurrently, and at least + * one of the threads invokes the <code>increment()</code> or + * <code>clear()</code> method, it must be synchronized externally.</p> + * + */ +public class Median extends Percentile implements Serializable { + + /** Serializable version identifier */ + private static final long serialVersionUID = -3961477041290915687L; + + /** Fixed quantile. */ + private static final double FIXED_QUANTILE_50 = 50.0; + + /** + * Default constructor. + */ + public Median() { + // No try-catch or advertised exception - arg is valid + super(FIXED_QUANTILE_50); + } + + /** + * Copy constructor, creates a new {@code Median} identical + * to the {@code original} + * + * @param original the {@code Median} instance to copy + * @throws NullArgumentException if original is null + */ + public Median(Median original) throws NullArgumentException { + super(original); + } + + /** + * Constructs a Median with the specific {@link EstimationType}, {@link NaNStrategy} and {@link PivotingStrategy}. + * + * @param estimationType one of the percentile {@link EstimationType estimation types} + * @param nanStrategy one of {@link NaNStrategy} to handle with NaNs + * @param kthSelector {@link KthSelector} to use for pivoting during search + * @throws MathIllegalArgumentException if p is not within (0,100] + * @throws NullArgumentException if type or NaNStrategy passed is null + */ + private Median(final EstimationType estimationType, final NaNStrategy nanStrategy, + final KthSelector kthSelector) + throws MathIllegalArgumentException { + super(FIXED_QUANTILE_50, estimationType, nanStrategy, kthSelector); + } + + /** {@inheritDoc} */ + @Override + public Median withEstimationType(final EstimationType newEstimationType) { + return new Median(newEstimationType, getNaNStrategy(), getKthSelector()); + } + + /** {@inheritDoc} */ + @Override + public Median withNaNStrategy(final NaNStrategy newNaNStrategy) { + return new Median(getEstimationType(), newNaNStrategy, getKthSelector()); + } + + /** {@inheritDoc} */ + @Override + public Median withKthSelector(final KthSelector newKthSelector) { + return new Median(getEstimationType(), getNaNStrategy(), newKthSelector); + } + +} |