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Provides a single jar containing all JAITools modules which you can
use instead of including individual modules in your project. Note:
It does not include the Jiffle scripting language or Jiffle image
operator.
/*
* Copyright (c) 2009-2011, Michael Bedward. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright notice, this
* list of conditions and the following disclaimer in the documentation and/or
* other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.jaitools.numeric;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
/**
* A simple numeric histogram class that uses the {@linkplain Range} class
* to define bins. New bins can be defined even after data had already been
* added to allow a histogram to adapt to the input data, however the new bins
* must not overlap with existing bins.
*
* @param the value type
* @author Michael Bedward
* @since 1.0
* @version $Id$
*/
public class Histogram {
/** Constant indicating that a value does not fall in any bin */
public static final int NO_BIN = -1;
private List bins;
private boolean needsSort;
/**
* Creates a new histogram.
*/
public Histogram() {
bins = new ArrayList();
}
/**
* Adds a new bin to the histogram.
*
* @param range the data range for this bin.
* @throws HistogramException if the new bin overlaps with an existing bin
*/
public void addBin(Range range) throws HistogramException {
for (Bin bin : bins) {
if (range.intersects(bin.range)) {
throw new HistogramException(range.toString() + " overlaps existing bin" + bin.toString());
}
}
bins.add(new Bin(range));
needsSort = true;
}
/**
* Adds a value to the histogram.
*
* @param value the value
*
* @return the index of the bin that the value was allocated to or
* {@link #NO_BIN}
*/
public int addValue(T value) {
int index = getBinForValue(value);
if (index != NO_BIN) {
bins.get(index).count++;
}
return index;
}
/**
* Adds a list of values to the histogram. This will be faster than
* adding values one at a time if the list is at least partially
* sorted.
*
* @param values input values
*/
public void addValues(List values) {
ensureBinsSorted();
int curIndex = NO_BIN;
Bin bin = null;
for (T value : values) {
int index = findBin(value);
if (index != NO_BIN) {
if (index != curIndex) {
bin = bins.get(index);
curIndex = index;
}
bin.count++ ;
}
}
}
/**
* Gets the bin index for a value. The value is not added to the histogram.
*
* @param value the value
*
* @return the bin index or {@link #NO_BIN}
*/
public int getBinForValue(T value) {
ensureBinsSorted();
return findBin(value);
}
/**
* Gets bin indices for a list of input values. The values are not added
* to the histogram.
*
* @param values input values
*
* @return a new {@code List} of bin indices
*/
public List getBinForValues(List values) {
List indices = new ArrayList();
for (T value : values) {
indices.add(getBinForValue(value));
}
return indices;
}
/**
* Gets the number of bins.
*
* @return number of bins
*/
public int size() {
return bins.size();
}
/**
* Gets the count of data items in each bin.
*
* @return the counts
*/
public List getCounts() {
List counts = new ArrayList();
for (Bin bin : bins) {
counts.add(bin.count);
}
return counts;
}
/**
* Finds the bin for the given value.
*
* @param value the value
*
* @return bin index or {@code NO_BIN}
*/
private int findBin(T value) {
int index = 0;
for (Bin bin : bins) {
if (bin.range.contains(value)) {
return index;
}
index++ ;
}
return NO_BIN;
}
/**
* Ensures that bins are sorted in ascending order.
*/
private void ensureBinsSorted() {
if (needsSort) {
Collections.sort(bins, new BinComparator());
needsSort = false;
}
}
/**
* A histogram bin.
*/
private class Bin {
Range range;
int count;
public Bin(Range r) {
this.range = new Range(r);
this.count = 0;
}
}
/**
* A comparator used to sort bins into ascending order based on their
* lower bound.
*/
private class BinComparator implements Comparator {
private RangeExtendedComparator rc = new RangeExtendedComparator();
public int compare(Bin b1, Bin b2) {
RangeExtendedComparator.Result result = rc.compare(b1.range, b2.range);
switch (result.getNotation().charAt(1)) {
case '<': return -1;
case '>': return 1;
default: return 0;
}
}
}
}