shuffle.c File Reference

Random shuffle and related functions. More...

#include "tpcclibConfig.h"
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#include <string.h>
#include "tpcextensions.h"
#include "tpcrand.h"

Go to the source code of this file.

Functions
void	randomShuffle (int *array, unsigned int n, MERTWI *mt)
	Random shuffle.
void	randomShuffleUnsigned (unsigned int *array, unsigned int n, MERTWI *mt)
	Random shuffle.
void	randomPermutation (int *array, unsigned int n, int a, MERTWI *mt)
	Random permutation for an array of signed integers.
void	randomPermutationUnsigned (unsigned int *array, unsigned int n, unsigned int a, MERTWI *mt)
	Random permutation for an array of unsigned integers.

Detailed Description

Random shuffle and related functions.

Definition in file shuffle.c.

Function Documentation

randomPermutation()

void randomPermutation	(	int *	array,
		unsigned int	n,
		int	a,
		MERTWI *	mt )

Random permutation for an array of signed integers.

Given (allocated) array of length n is filled with random permutation of numbers (signed integers) in the range [a:n+a-1]; that is, each number once in random order.

Precondition

Prepare the Mersenne Twister, for example using code MERTWI mt; mertwiInit(&mt); mertwiInitWithSeed64(&mt, mertwiSeed64());

See also

randomPermutationUnsigned, randomShuffle

Parameters

array	Allocated array to be filled.
n	Length of array.
a	Smallest integer value.
mt	Pointer to data structure for Mersenne Twister MT19937 pseudo-random number generator.

Definition at line 80 of file shuffle.c.

  {
  if(n<1 || array==NULL) return;
  int i;
  for(i=0; i<(int)n; i++) array[i]=i+a;
  randomShuffle(array, n, mt);
}

randomPermutationUnsigned()

void randomPermutationUnsigned	(	unsigned int *	array,
		unsigned int	n,
		unsigned int	a,
		MERTWI *	mt )

Random permutation for an array of unsigned integers.

Given (allocated) array of length n is filled with random permutation of numbers (unsigned integers) in the range [a:n+a-1]; that is, each number once in random order.

Precondition

Prepare the Mersenne Twister, for example using code MERTWI mt; mertwiInit(&mt); mertwiInitWithSeed64(&mt, mertwiSeed64());

See also

randomPermutation, randomShuffleUnsigned

Parameters

array	Allocated array to be filled.
n	Length of array.
a	Smallest integer value.
mt	Pointer to data structure for Mersenne Twister MT19937 pseudo-random number generator.

Definition at line 106 of file shuffle.c.

  {
  if(n<1 || array==NULL) return;
  unsigned int i;
  for(i=0; i<n; i++) array[i]=i+a;
  randomShuffleUnsigned(array, n, mt);
}

randomShuffle()

void randomShuffle	(	int *	array,
		unsigned int	n,
		MERTWI *	mt )

Random shuffle.

Arrange the n elements of integer array in random order. Only effective if N is much smaller than UINT64_MAX.

Precondition

Prepare the Mersenne Twister, for example using code MERTWI mt; mertwiInit(&mt); mertwiInitWithSeed64(&mt, mertwiSeed64());

See also

randomShuffleUnsigned

Parameters

array	Integer array to be shuffled.
n	Array length.
mt	Pointer to data structure for Mersenne Twister MT19937 pseudo-random number generator.

Definition at line 27 of file shuffle.c.

  {
  if(n<=1 || array==NULL) return;
  unsigned int i, j;
  int tmp;
  for(i=0; i<n-1; i++) {
    j=i+mertwiRandomInt64(mt)/(UINT64_MAX/(n-i)+1);
    tmp=array[j]; array[j]=array[i]; array[i]=tmp;
  }
}

Referenced by randomPermutation().

randomShuffleUnsigned()

void randomShuffleUnsigned	(	unsigned int *	array,
		unsigned int	n,
		MERTWI *	mt )

Random shuffle.

Arrange the n elements of unsigned integer array in random order. Only effective if N is much smaller than UINT64_MAX.

Precondition

Prepare the Mersenne Twister, for example using code MERTWI mt; mertwiInit(&mt); mertwiInitWithSeed64(&mt, mertwiSeed64());

See also

randomShuffle, randomPermutation

Parameters

array	Integer array to be shuffled.
n	Array length.
mt	Pointer to data structure for Mersenne Twister MT19937 pseudo-random number generator.

Definition at line 54 of file shuffle.c.

  {
  if(n<=1 || array==NULL) return;
  unsigned int i, j, tmp;
  for(i=0; i<n-1; i++) {
    j=i+mertwiRandomInt64(mt)/(UINT64_MAX/(n-i)+1);
    tmp=array[j]; array[j]=array[i]; array[i]=tmp;
  }
}

Referenced by randomPermutationUnsigned().