| /* |
| * 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; |
| |
| import java.io.Serializable; |
| import java.text.NumberFormat; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Iterator; |
| import java.util.Comparator; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Map.Entry; |
| import java.util.SortedMap; |
| import java.util.TreeMap; |
| |
| import org.apache.commons.math3.exception.MathIllegalArgumentException; |
| import org.apache.commons.math3.exception.NullArgumentException; |
| import org.apache.commons.math3.exception.util.LocalizedFormats; |
| import org.apache.commons.math3.util.MathUtils; |
| |
| /** |
| * Maintains a frequency distribution. |
| * <p> |
| * Accepts int, long, char or Comparable values. New values added must be |
| * comparable to those that have been added, otherwise the add method will |
| * throw an IllegalArgumentException.</p> |
| * <p> |
| * Integer values (int, long, Integer, Long) are not distinguished by type -- |
| * i.e. <code>addValue(Long.valueOf(2)), addValue(2), addValue(2l)</code> all have |
| * the same effect (similarly for arguments to <code>getCount,</code> etc.).</p> |
| * <p>NOTE: byte and short values will be implicitly converted to int values |
| * by the compiler, thus there are no explicit overloaded methods for these |
| * primitive types.</p> |
| * <p> |
| * char values are converted by <code>addValue</code> to Character instances. |
| * As such, these values are not comparable to integral values, so attempts |
| * to combine integral types with chars in a frequency distribution will fail. |
| * </p> |
| * <p> |
| * Float is not coerced to Double. |
| * Since they are not Comparable with each other the user must do any necessary coercion. |
| * Float.NaN and Double.NaN are not treated specially; they may occur in input and will |
| * occur in output if appropriate. |
| * </b> |
| * <p> |
| * The values are ordered using the default (natural order), unless a |
| * <code>Comparator</code> is supplied in the constructor.</p> |
| * |
| */ |
| public class Frequency implements Serializable { |
| |
| /** Serializable version identifier */ |
| private static final long serialVersionUID = -3845586908418844111L; |
| |
| /** underlying collection */ |
| private final SortedMap<Comparable<?>, Long> freqTable; |
| |
| /** |
| * Default constructor. |
| */ |
| public Frequency() { |
| freqTable = new TreeMap<Comparable<?>, Long>(); |
| } |
| |
| /** |
| * Constructor allowing values Comparator to be specified. |
| * |
| * @param comparator Comparator used to order values |
| */ |
| @SuppressWarnings("unchecked") // TODO is the cast OK? |
| public Frequency(Comparator<?> comparator) { |
| freqTable = new TreeMap<Comparable<?>, Long>((Comparator<? super Comparable<?>>) comparator); |
| } |
| |
| /** |
| * Return a string representation of this frequency distribution. |
| * |
| * @return a string representation. |
| */ |
| @Override |
| public String toString() { |
| NumberFormat nf = NumberFormat.getPercentInstance(); |
| StringBuilder outBuffer = new StringBuilder(); |
| outBuffer.append("Value \t Freq. \t Pct. \t Cum Pct. \n"); |
| Iterator<Comparable<?>> iter = freqTable.keySet().iterator(); |
| while (iter.hasNext()) { |
| Comparable<?> value = iter.next(); |
| outBuffer.append(value); |
| outBuffer.append('\t'); |
| outBuffer.append(getCount(value)); |
| outBuffer.append('\t'); |
| outBuffer.append(nf.format(getPct(value))); |
| outBuffer.append('\t'); |
| outBuffer.append(nf.format(getCumPct(value))); |
| outBuffer.append('\n'); |
| } |
| return outBuffer.toString(); |
| } |
| |
| /** |
| * Adds 1 to the frequency count for v. |
| * <p> |
| * If other objects have already been added to this Frequency, v must |
| * be comparable to those that have already been added. |
| * </p> |
| * |
| * @param v the value to add. |
| * @throws MathIllegalArgumentException if <code>v</code> is not comparable with previous entries |
| */ |
| public void addValue(Comparable<?> v) throws MathIllegalArgumentException { |
| incrementValue(v, 1); |
| } |
| |
| /** |
| * Adds 1 to the frequency count for v. |
| * |
| * @param v the value to add. |
| * @throws MathIllegalArgumentException if the table contains entries not |
| * comparable to Long |
| */ |
| public void addValue(int v) throws MathIllegalArgumentException { |
| addValue(Long.valueOf(v)); |
| } |
| |
| /** |
| * Adds 1 to the frequency count for v. |
| * |
| * @param v the value to add. |
| * @throws MathIllegalArgumentException if the table contains entries not |
| * comparable to Long |
| */ |
| public void addValue(long v) throws MathIllegalArgumentException { |
| addValue(Long.valueOf(v)); |
| } |
| |
| /** |
| * Adds 1 to the frequency count for v. |
| * |
| * @param v the value to add. |
| * @throws MathIllegalArgumentException if the table contains entries not |
| * comparable to Char |
| */ |
| public void addValue(char v) throws MathIllegalArgumentException { |
| addValue(Character.valueOf(v)); |
| } |
| |
| /** |
| * Increments the frequency count for v. |
| * <p> |
| * If other objects have already been added to this Frequency, v must |
| * be comparable to those that have already been added. |
| * </p> |
| * |
| * @param v the value to add. |
| * @param increment the amount by which the value should be incremented |
| * @throws MathIllegalArgumentException if <code>v</code> is not comparable with previous entries |
| * @since 3.1 |
| */ |
| public void incrementValue(Comparable<?> v, long increment) throws MathIllegalArgumentException { |
| Comparable<?> obj = v; |
| if (v instanceof Integer) { |
| obj = Long.valueOf(((Integer) v).longValue()); |
| } |
| try { |
| Long count = freqTable.get(obj); |
| if (count == null) { |
| freqTable.put(obj, Long.valueOf(increment)); |
| } else { |
| freqTable.put(obj, Long.valueOf(count.longValue() + increment)); |
| } |
| } catch (ClassCastException ex) { |
| //TreeMap will throw ClassCastException if v is not comparable |
| throw new MathIllegalArgumentException( |
| LocalizedFormats.INSTANCES_NOT_COMPARABLE_TO_EXISTING_VALUES, |
| v.getClass().getName()); |
| } |
| } |
| |
| /** |
| * Increments the frequency count for v. |
| * <p> |
| * If other objects have already been added to this Frequency, v must |
| * be comparable to those that have already been added. |
| * </p> |
| * |
| * @param v the value to add. |
| * @param increment the amount by which the value should be incremented |
| * @throws MathIllegalArgumentException if the table contains entries not |
| * comparable to Long |
| * @since 3.3 |
| */ |
| public void incrementValue(int v, long increment) throws MathIllegalArgumentException { |
| incrementValue(Long.valueOf(v), increment); |
| } |
| |
| /** |
| * Increments the frequency count for v. |
| * <p> |
| * If other objects have already been added to this Frequency, v must |
| * be comparable to those that have already been added. |
| * </p> |
| * |
| * @param v the value to add. |
| * @param increment the amount by which the value should be incremented |
| * @throws MathIllegalArgumentException if the table contains entries not |
| * comparable to Long |
| * @since 3.3 |
| */ |
| public void incrementValue(long v, long increment) throws MathIllegalArgumentException { |
| incrementValue(Long.valueOf(v), increment); |
| } |
| |
| /** |
| * Increments the frequency count for v. |
| * <p> |
| * If other objects have already been added to this Frequency, v must |
| * be comparable to those that have already been added. |
| * </p> |
| * |
| * @param v the value to add. |
| * @param increment the amount by which the value should be incremented |
| * @throws MathIllegalArgumentException if the table contains entries not |
| * comparable to Char |
| * @since 3.3 |
| */ |
| public void incrementValue(char v, long increment) throws MathIllegalArgumentException { |
| incrementValue(Character.valueOf(v), increment); |
| } |
| |
| /** Clears the frequency table */ |
| public void clear() { |
| freqTable.clear(); |
| } |
| |
| /** |
| * Returns an Iterator over the set of values that have been added. |
| * <p> |
| * If added values are integral (i.e., integers, longs, Integers, or Longs), |
| * they are converted to Longs when they are added, so the objects returned |
| * by the Iterator will in this case be Longs.</p> |
| * |
| * @return values Iterator |
| */ |
| public Iterator<Comparable<?>> valuesIterator() { |
| return freqTable.keySet().iterator(); |
| } |
| |
| /** |
| * Return an Iterator over the set of keys and values that have been added. |
| * Using the entry set to iterate is more efficient in the case where you |
| * need to access respective counts as well as values, since it doesn't |
| * require a "get" for every key...the value is provided in the Map.Entry. |
| * <p> |
| * If added values are integral (i.e., integers, longs, Integers, or Longs), |
| * they are converted to Longs when they are added, so the values of the |
| * map entries returned by the Iterator will in this case be Longs.</p> |
| * |
| * @return entry set Iterator |
| * @since 3.1 |
| */ |
| public Iterator<Map.Entry<Comparable<?>, Long>> entrySetIterator() { |
| return freqTable.entrySet().iterator(); |
| } |
| |
| //------------------------------------------------------------------------- |
| |
| /** |
| * Returns the sum of all frequencies. |
| * |
| * @return the total frequency count. |
| */ |
| public long getSumFreq() { |
| long result = 0; |
| Iterator<Long> iterator = freqTable.values().iterator(); |
| while (iterator.hasNext()) { |
| result += iterator.next().longValue(); |
| } |
| return result; |
| } |
| |
| /** |
| * Returns the number of values equal to v. |
| * Returns 0 if the value is not comparable. |
| * |
| * @param v the value to lookup. |
| * @return the frequency of v. |
| */ |
| public long getCount(Comparable<?> v) { |
| if (v instanceof Integer) { |
| return getCount(((Integer) v).longValue()); |
| } |
| long result = 0; |
| try { |
| Long count = freqTable.get(v); |
| if (count != null) { |
| result = count.longValue(); |
| } |
| } catch (ClassCastException ex) { // NOPMD |
| // ignore and return 0 -- ClassCastException will be thrown if value is not comparable |
| } |
| return result; |
| } |
| |
| /** |
| * Returns the number of values equal to v. |
| * |
| * @param v the value to lookup. |
| * @return the frequency of v. |
| */ |
| public long getCount(int v) { |
| return getCount(Long.valueOf(v)); |
| } |
| |
| /** |
| * Returns the number of values equal to v. |
| * |
| * @param v the value to lookup. |
| * @return the frequency of v. |
| */ |
| public long getCount(long v) { |
| return getCount(Long.valueOf(v)); |
| } |
| |
| /** |
| * Returns the number of values equal to v. |
| * |
| * @param v the value to lookup. |
| * @return the frequency of v. |
| */ |
| public long getCount(char v) { |
| return getCount(Character.valueOf(v)); |
| } |
| |
| /** |
| * Returns the number of values in the frequency table. |
| * |
| * @return the number of unique values that have been added to the frequency table. |
| * @see #valuesIterator() |
| */ |
| public int getUniqueCount(){ |
| return freqTable.keySet().size(); |
| } |
| |
| /** |
| * Returns the percentage of values that are equal to v |
| * (as a proportion between 0 and 1). |
| * <p> |
| * Returns <code>Double.NaN</code> if no values have been added. |
| * Returns 0 if at least one value has been added, but v is not comparable |
| * to the values set.</p> |
| * |
| * @param v the value to lookup |
| * @return the proportion of values equal to v |
| */ |
| public double getPct(Comparable<?> v) { |
| final long sumFreq = getSumFreq(); |
| if (sumFreq == 0) { |
| return Double.NaN; |
| } |
| return (double) getCount(v) / (double) sumFreq; |
| } |
| |
| /** |
| * Returns the percentage of values that are equal to v |
| * (as a proportion between 0 and 1). |
| * |
| * @param v the value to lookup |
| * @return the proportion of values equal to v |
| */ |
| public double getPct(int v) { |
| return getPct(Long.valueOf(v)); |
| } |
| |
| /** |
| * Returns the percentage of values that are equal to v |
| * (as a proportion between 0 and 1). |
| * |
| * @param v the value to lookup |
| * @return the proportion of values equal to v |
| */ |
| public double getPct(long v) { |
| return getPct(Long.valueOf(v)); |
| } |
| |
| /** |
| * Returns the percentage of values that are equal to v |
| * (as a proportion between 0 and 1). |
| * |
| * @param v the value to lookup |
| * @return the proportion of values equal to v |
| */ |
| public double getPct(char v) { |
| return getPct(Character.valueOf(v)); |
| } |
| |
| //----------------------------------------------------------------------------------------- |
| |
| /** |
| * Returns the cumulative frequency of values less than or equal to v. |
| * <p> |
| * Returns 0 if v is not comparable to the values set.</p> |
| * |
| * @param v the value to lookup. |
| * @return the proportion of values equal to v |
| */ |
| @SuppressWarnings({ "rawtypes", "unchecked" }) |
| public long getCumFreq(Comparable<?> v) { |
| if (getSumFreq() == 0) { |
| return 0; |
| } |
| if (v instanceof Integer) { |
| return getCumFreq(((Integer) v).longValue()); |
| } |
| Comparator<Comparable<?>> c = (Comparator<Comparable<?>>) freqTable.comparator(); |
| if (c == null) { |
| c = new NaturalComparator(); |
| } |
| long result = 0; |
| |
| try { |
| Long value = freqTable.get(v); |
| if (value != null) { |
| result = value.longValue(); |
| } |
| } catch (ClassCastException ex) { |
| return result; // v is not comparable |
| } |
| |
| if (c.compare(v, freqTable.firstKey()) < 0) { |
| return 0; // v is comparable, but less than first value |
| } |
| |
| if (c.compare(v, freqTable.lastKey()) >= 0) { |
| return getSumFreq(); // v is comparable, but greater than the last value |
| } |
| |
| Iterator<Comparable<?>> values = valuesIterator(); |
| while (values.hasNext()) { |
| Comparable<?> nextValue = values.next(); |
| if (c.compare(v, nextValue) > 0) { |
| result += getCount(nextValue); |
| } else { |
| return result; |
| } |
| } |
| return result; |
| } |
| |
| /** |
| * Returns the cumulative frequency of values less than or equal to v. |
| * <p> |
| * Returns 0 if v is not comparable to the values set.</p> |
| * |
| * @param v the value to lookup |
| * @return the proportion of values equal to v |
| */ |
| public long getCumFreq(int v) { |
| return getCumFreq(Long.valueOf(v)); |
| } |
| |
| /** |
| * Returns the cumulative frequency of values less than or equal to v. |
| * <p> |
| * Returns 0 if v is not comparable to the values set.</p> |
| * |
| * @param v the value to lookup |
| * @return the proportion of values equal to v |
| */ |
| public long getCumFreq(long v) { |
| return getCumFreq(Long.valueOf(v)); |
| } |
| |
| /** |
| * Returns the cumulative frequency of values less than or equal to v. |
| * <p> |
| * Returns 0 if v is not comparable to the values set.</p> |
| * |
| * @param v the value to lookup |
| * @return the proportion of values equal to v |
| */ |
| public long getCumFreq(char v) { |
| return getCumFreq(Character.valueOf(v)); |
| } |
| |
| //---------------------------------------------------------------------------------------------- |
| |
| /** |
| * Returns the cumulative percentage of values less than or equal to v |
| * (as a proportion between 0 and 1). |
| * <p> |
| * Returns <code>Double.NaN</code> if no values have been added. |
| * Returns 0 if at least one value has been added, but v is not comparable |
| * to the values set.</p> |
| * |
| * @param v the value to lookup |
| * @return the proportion of values less than or equal to v |
| */ |
| public double getCumPct(Comparable<?> v) { |
| final long sumFreq = getSumFreq(); |
| if (sumFreq == 0) { |
| return Double.NaN; |
| } |
| return (double) getCumFreq(v) / (double) sumFreq; |
| } |
| |
| /** |
| * Returns the cumulative percentage of values less than or equal to v |
| * (as a proportion between 0 and 1). |
| * <p> |
| * Returns 0 if v is not comparable to the values set.</p> |
| * |
| * @param v the value to lookup |
| * @return the proportion of values less than or equal to v |
| */ |
| public double getCumPct(int v) { |
| return getCumPct(Long.valueOf(v)); |
| } |
| |
| /** |
| * Returns the cumulative percentage of values less than or equal to v |
| * (as a proportion between 0 and 1). |
| * <p> |
| * Returns 0 if v is not comparable to the values set.</p> |
| * |
| * @param v the value to lookup |
| * @return the proportion of values less than or equal to v |
| */ |
| public double getCumPct(long v) { |
| return getCumPct(Long.valueOf(v)); |
| } |
| |
| /** |
| * Returns the cumulative percentage of values less than or equal to v |
| * (as a proportion between 0 and 1). |
| * <p> |
| * Returns 0 if v is not comparable to the values set.</p> |
| * |
| * @param v the value to lookup |
| * @return the proportion of values less than or equal to v |
| */ |
| public double getCumPct(char v) { |
| return getCumPct(Character.valueOf(v)); |
| } |
| |
| /** |
| * Returns the mode value(s) in comparator order. |
| * |
| * @return a list containing the value(s) which appear most often. |
| * @since 3.3 |
| */ |
| public List<Comparable<?>> getMode() { |
| long mostPopular = 0; // frequencies are always positive |
| |
| // Get the max count first, so we avoid having to recreate the List each time |
| for(Long l : freqTable.values()) { |
| long frequency = l.longValue(); |
| if (frequency > mostPopular) { |
| mostPopular = frequency; |
| } |
| } |
| |
| List<Comparable<?>> modeList = new ArrayList<Comparable<?>>(); |
| for (Entry<Comparable<?>, Long> ent : freqTable.entrySet()) { |
| long frequency = ent.getValue().longValue(); |
| if (frequency == mostPopular) { |
| modeList.add(ent.getKey()); |
| } |
| } |
| return modeList; |
| } |
| |
| //---------------------------------------------------------------------------------------------- |
| |
| /** |
| * Merge another Frequency object's counts into this instance. |
| * This Frequency's counts will be incremented (or set when not already set) |
| * by the counts represented by other. |
| * |
| * @param other the other {@link Frequency} object to be merged |
| * @throws NullArgumentException if {@code other} is null |
| * @since 3.1 |
| */ |
| public void merge(final Frequency other) throws NullArgumentException { |
| MathUtils.checkNotNull(other, LocalizedFormats.NULL_NOT_ALLOWED); |
| |
| final Iterator<Map.Entry<Comparable<?>, Long>> iter = other.entrySetIterator(); |
| while (iter.hasNext()) { |
| final Map.Entry<Comparable<?>, Long> entry = iter.next(); |
| incrementValue(entry.getKey(), entry.getValue().longValue()); |
| } |
| } |
| |
| /** |
| * Merge a {@link Collection} of {@link Frequency} objects into this instance. |
| * This Frequency's counts will be incremented (or set when not already set) |
| * by the counts represented by each of the others. |
| * |
| * @param others the other {@link Frequency} objects to be merged |
| * @throws NullArgumentException if the collection is null |
| * @since 3.1 |
| */ |
| public void merge(final Collection<Frequency> others) throws NullArgumentException { |
| MathUtils.checkNotNull(others, LocalizedFormats.NULL_NOT_ALLOWED); |
| |
| for (final Frequency freq : others) { |
| merge(freq); |
| } |
| } |
| |
| //---------------------------------------------------------------------------------------------- |
| |
| /** |
| * A Comparator that compares comparable objects using the |
| * natural order. Copied from Commons Collections ComparableComparator. |
| * @param <T> the type of the objects compared |
| */ |
| private static class NaturalComparator<T extends Comparable<T>> implements Comparator<Comparable<T>>, Serializable { |
| |
| /** Serializable version identifier */ |
| private static final long serialVersionUID = -3852193713161395148L; |
| |
| /** |
| * Compare the two {@link Comparable Comparable} arguments. |
| * This method is equivalent to: |
| * <pre>(({@link Comparable Comparable})o1).{@link Comparable#compareTo compareTo}(o2)</pre> |
| * |
| * @param o1 the first object |
| * @param o2 the second object |
| * @return result of comparison |
| * @throws NullPointerException when <i>o1</i> is <code>null</code>, |
| * or when <code>((Comparable)o1).compareTo(o2)</code> does |
| * @throws ClassCastException when <i>o1</i> is not a {@link Comparable Comparable}, |
| * or when <code>((Comparable)o1).compareTo(o2)</code> does |
| */ |
| @SuppressWarnings("unchecked") // cast to (T) may throw ClassCastException, see Javadoc |
| public int compare(Comparable<T> o1, Comparable<T> o2) { |
| return o1.compareTo((T) o2); |
| } |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public int hashCode() { |
| final int prime = 31; |
| int result = 1; |
| result = prime * result + |
| ((freqTable == null) ? 0 : freqTable.hashCode()); |
| return result; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) { |
| return true; |
| } |
| if (!(obj instanceof Frequency)) { |
| return false; |
| } |
| Frequency other = (Frequency) obj; |
| if (freqTable == null) { |
| if (other.freqTable != null) { |
| return false; |
| } |
| } else if (!freqTable.equals(other.freqTable)) { |
| return false; |
| } |
| return true; |
| } |
| |
| } |