com.tdunning.math.stats

Class Sort

java.lang.Object

com.tdunning.math.stats.Sort

public class Sort
extends Object

Static sorting methods

Constructor Summary

Constructors

Constructor and Description
Sort()

Method Summary

Modifier and Type	Method and Description
static void	checkPartition(int[] order, double[] values, double pivotValue, int start, int low, int high, int end) Check that a partition step was done correctly.
static void	reverse(double[] order, int offset, int length) Reverses part of an array.
static void	reverse(int[] order) Reverses an array in-place.
static void	reverse(int[] order, int offset, int length) Reverses part of an array.
static void	sort(double[] key, double[]... values) Quick sort in place of several paired arrays.
static void	sort(double[] key, int start, int n, double[]... values) Quick sort using an index array.
static boolean	sort(int[] order, double[] values, double[] weights, int n) Two-key quick sort on (values, weights) using an index array
static void	stableSort(int[] order, double[] values, int n) Single-key stabilized quick sort on using an index array

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Sort

public Sort()

Method Detail

stableSort

public static void stableSort(int[] order,
                              double[] values,
                              int n)

Single-key stabilized quick sort on using an index array

Parameters:

order - Indexes into values

values - The values to sort.

n - The number of values to sort

sort

public static boolean sort(int[] order,
                           double[] values,
                           double[] weights,
                           int n)

Two-key quick sort on (values, weights) using an index array

Parameters:

order - Indexes into values

values - The values to sort.

weights - The secondary sort key

n - The number of values to sort

Returns:

true if the values were already sorted

sort

public static void sort(double[] key,
                        double[]... values)

Quick sort in place of several paired arrays. On return, keys[...] is in order and the values[] arrays will be reordered as well in the same way.

Parameters:

key - Values to sort on

values - The auxilliary values to sort.

sort

public static void sort(double[] key,
                        int start,
                        int n,
                        double[]... values)

Quick sort using an index array. On return, values[order[i]] is in order as i goes start..n

Parameters:

key - Values to sort on

start - The first element to sort

n - The number of values to sort

values - The auxilliary values to sort.

checkPartition

public static void checkPartition(int[] order,
                                  double[] values,
                                  double pivotValue,
                                  int start,
                                  int low,
                                  int high,
                                  int end)

Check that a partition step was done correctly. For debugging and testing.

Parameters:

order - The array of indexes representing a permutation of the keys.

values - The keys to sort.

pivotValue - The value that splits the data

start - The beginning of the data of interest.

low - Values from start (inclusive) to low (exclusive) are < pivotValue.

high - Values from low to high are equal to the pivot.

end - Values from high to end are above the pivot.

reverse

public static void reverse(int[] order)

Reverses an array in-place.

Parameters:

order - The array to reverse

reverse

public static void reverse(int[] order,
                           int offset,
                           int length)

Reverses part of an array. See reverse(int[])

Parameters:

order - The array containing the data to reverse.

offset - Where to start reversing.

length - How many elements to reverse

reverse

public static void reverse(double[] order,
                           int offset,
                           int length)

Reverses part of an array. See reverse(int[])

Parameters:

order - The array containing the data to reverse.

offset - Where to start reversing.

length - How many elements to reverse