umontreal.iro.lecuyer.hups

Class CycleBasedPointSetBase2

java.lang.Object

umontreal.iro.lecuyer.hups.PointSet

umontreal.iro.lecuyer.hups.CycleBasedPointSet

umontreal.iro.lecuyer.hups.CycleBasedPointSetBase2

Direct Known Subclasses:

F2wCycleBasedLFSR, F2wCycleBasedPolyLCG

public abstract class CycleBasedPointSetBase2
extends CycleBasedPointSet

Similar to CycleBasedPointSet, except that the successive values in the cycles are stored as integers in the range {0,..., 2^k -1}, where 1 <= k <= 31. The output values u_{i, j} are obtained by dividing these integer values by 2^k. Point sets where the successive coordinates of each point are obtained via linear recurrences modulo 2 (e.g., linear feedback shift registers or Korobov-type polynomial lattice rules) are naturally expressed in this form. Storing the integers 2^ku_{i, j} instead of the u_{i, j} themselves makes it easier to apply randomizations such as digital random shifts in base 2, which are applied to the bits before transforming the value to a real number u_{i, j}. When a random digital shift is performed, it applies a bitwise exclusive-or of all the points with a single random point.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	CycleBasedPointSetBase2.CycleBasedPointSetBase2Iterator

Nested classes/interfaces inherited from class umontreal.iro.lecuyer.hups.CycleBasedPointSet

CycleBasedPointSet.CycleBasedPointSetIterator

Constructor Summary

Constructors

Constructor and Description
CycleBasedPointSetBase2()

Method Summary

Methods

Modifier and Type	Method and Description
void	addRandomShift(int d1, int d2, RandomStream stream) Adds a random digital shift in base 2 to all the points of the point set, using stream stream to generate the random numbers, for coordinates d1 to d2 - 1.
void	clearRandomShift() Erases the current random shift, if any.
java.lang.String	formatPoints() Same as invoking formatPoints(n, d) with n and d equal to the number of points and the dimension of this object, respectively.
double	getCoordinate(int i, int j) Returns ui, j, the coordinate j of the point i.
PointSetIterator	iterator() Constructs and returns a point set iterator.

Methods inherited from class umontreal.iro.lecuyer.hups.CycleBasedPointSet

getDimension, toString

Methods inherited from class umontreal.iro.lecuyer.hups.PointSet

addRandomShift, addRandomShift, addRandomShift, formatPoints, formatPoints, formatPoints, formatPointsBase, formatPointsBase, formatPointsBase, formatPointsBase, formatPointsNumbered, formatPointsNumbered, getNumPoints, getStream, randomize, randomize, randomize, randomize, randomize, setStream, unrandomize

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

CycleBasedPointSetBase2

public CycleBasedPointSetBase2()

Method Detail

getCoordinate

public double getCoordinate(int i,
                   int j)

Description copied from class: PointSet

Returns u_{i, j}, the coordinate j of the point i.

Overrides:

getCoordinate in class CycleBasedPointSet

Parameters:

i - index of the point to look for

j - index of the coordinate to look for

Returns:

the value of u_{i, j}

iterator

public PointSetIterator iterator()

Description copied from class: PointSet

Constructs and returns a point set iterator. The default implementation returns an iterator that uses the method getCoordinate (i,j) to iterate over the points and coordinates, but subclasses can reimplement it for better efficiency.

Overrides:

iterator in class CycleBasedPointSet

Returns:

point set iterator for the point set

addRandomShift

public void addRandomShift(int d1,
                  int d2,
                  RandomStream stream)

Adds a random digital shift in base 2 to all the points of the point set, using stream stream to generate the random numbers, for coordinates d1 to d2 - 1. This applies a bitwise exclusive-or of all the points with a single random point.

Overrides:

addRandomShift in class CycleBasedPointSet

stream - Stream used to generate random numbers

clearRandomShift

public void clearRandomShift()

Description copied from class: PointSet

Erases the current random shift, if any.

Overrides:

clearRandomShift in class CycleBasedPointSet

formatPoints

public java.lang.String formatPoints()

Description copied from class: PointSet

Same as invoking formatPoints(n, d) with n and d equal to the number of points and the dimension of this object, respectively.

Overrides:

formatPoints in class CycleBasedPointSet

Returns:

string representation of all the points in the point set