Package etomica.math.discrete

Class PermutationIterator

java.lang.Object

etomica.math.discrete.PermutationIterator

All Implemented Interfaces:

IndexIterator, java.io.Serializable

public class PermutationIterator
extends java.lang.Object
implements IndexIterator, java.io.Serializable

Iterator that returns different permutations of a sequence of integers when called in successive iterations. For example, if constructed with n = 3, will return, in successive calls to next(), the arrays {0,1,2}, {0,2,1}, {2,0,1}, {1,0,2}, {1,2,0}, {2,1,0}.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
PermutationIterator(int n)

Method Summary

Modifier and Type	Method	Description
int	getD()
boolean	hasNext()
static void	main(java.lang.String[] args)
static int[][]	matrixPermutation(int[] p, int[][] a)	Returns a new matrix formed by permuting the rows and columns of the given matrix according to the permuation list p.
int[]	next()
void	reset()

Methods inherited from class java.lang.Object

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

Constructor Detail

PermutationIterator

public PermutationIterator(int n)

Method Detail

reset

public void reset()

Specified by:

reset in interface IndexIterator

hasNext

public boolean hasNext()

Specified by:

hasNext in interface IndexIterator

next

public int[] next()

Specified by:

next in interface IndexIterator

matrixPermutation

public static int[][] matrixPermutation(int[] p,
                                        int[][] a)

Returns a new matrix formed by permuting the rows and columns of the given matrix according to the permuation list p. The list p[i] is such that it gives the (row/column) index in matrix a from which the element of the new matrix is taken. So b(p[i],p[j]) will be equal to a(i,j). The original matrix a is unchanged.

Parameters:

p - permutation list

a - original matrix

Returns:

int[][] permuted matrix

getD

public int getD()

Specified by:

getD in interface IndexIterator

main

public static void main(java.lang.String[] args)