SSJ API Documentation
Stochastic Simulation in Java
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umontreal.ssj.hups.StratifiedUnitCube Class Reference

This class implements a stratification of the unit cube in rectangular boxes of same size and orientation. More...

Inheritance diagram for umontreal.ssj.hups.StratifiedUnitCube:
umontreal.ssj.hups.CachedPointSet umontreal.ssj.hups.PointSet

Public Member Functions

 StratifiedUnitCube (int[] k, int dim)
 Builds a stratified points set in dim dimensions, with k[j] intervals in dimension j.
 StratifiedUnitCube (int k, int dim)
 Same as StratifiedUnitCube (int[] k, int dim) with all coordinates of the vector k equal to the integer k.
void randomize (RandomStream stream)
 This randomization generates one point randomly in its corresponding box, for each of the \(n\) boxes.
void addRandomShift (int fromDim, int toDim, RandomStream stream)
 Random shifts and partial randomizations are irrelevant here, so this method is redefined to be equivalent to randomize (stream).
void randomize (PointSetRandomization rand)
 Randomizes the points using stratification, regardless of what rand is.
String toString ()
 Formats a string that contains information about the point set.
Public Member Functions inherited from umontreal.ssj.hups.CachedPointSet
 CachedPointSet (PointSet p, int fromPoint, int toPoint, int fromDim, int toDim)
 Creates a new PointSet object that contains an array storing the coordinates fromDim (inclusive) to toDim (exclusive) of the points numbered fromPoint (inclusive) to toPoint (exclusive) of p.
 CachedPointSet (PointSet p, int n, int dim)
 Same as CachedPointSet(p, 0, n, 0, dim).
 CachedPointSet (PointSet p)
 Creates a new PointSet object that contains an array storing the points of p.
PointSetIterator iterator ()
 Constructs and returns a point set iterator that gets the values directly from the cached array.
void setRandomizeParent (boolean randomizeParent)
 If randomizeParent is true, calls to randomize() will be defered to the parent point set (this is the default); otherwise, the randomize method of the PointSetRandomization instance is invoked with this CachedPointSet instance as its argument.
void sortByCoordinate (int j)
 Sorts the cached points by increasing order of coordinate j.
void stripCoordinates (int d)
 Removes the first d coordinates of each cached point.
double getCoordinate (int i, int j)
 Returns \(u_{i,j}\), the coordinate \(j\) of the point \(i\).
PointSet getParentPointSet ()
 Returns the reference point set that was passed to the constructor.
Public Member Functions inherited from umontreal.ssj.hups.PointSet
int getDimension ()
 Returns the dimension (number of available coordinates) of the points.
int getNumPoints ()
 Returns the number of points.
void addRandomShift (RandomStream stream)
 Same as addRandomShift(0, dim, stream), where dim is the dimension of the point set.
void addRandomShift (int d1, int d2)
 Refreshes the random shift (generates new uniform values for the random shift coordinates) for coordinates d1 to d2-1, using the saved shiftStream.
void addRandomShift ()
 Same as addRandomShift(0, dim), where dim is the dimension of the point set.
void clearRandomShift ()
 Erases the current random shift, if any.
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.
String formatPoints (int n, int d)
 Formats a string that displays the same information as returned by toString, together with the first \(d\) coordinates of the first.
String formatPoints (PointSetIterator iter)
 Same as invoking formatPoints(iter, n, d) with \(n\) and \(d\) equal to the number of points and the dimension, respectively.
String formatPoints (PointSetIterator iter, int n, int d)
 Same as invoking formatPoints(n, d), but prints the points by calling iter repeatedly.
String formatPointsBase (int b)
 Similar to formatPoints(), but the points coordinates are printed in base \(b\).
String formatPointsBase (int n, int d, int b)
 Similar to formatPoints(n, d), but the points coordinates are printed in base \(b\).
String formatPointsBase (PointSetIterator iter, int b)
 Similar to formatPoints(iter), but the points coordinates are printed in base.
String formatPointsBase (PointSetIterator iter, int n, int d, int b)
 Similar to formatPoints(iter, n, d), but the points coordinates are printed in base \(b\).
String formatPointsNumbered ()
 Same as invoking formatPointsNumbered(n, d) with \(n\) and \(d\) equal to the number of points and the dimension, respectively.
String formatPointsNumbered (int n, int d)
 Same as invoking formatPoints(n,d), except that the points are numbered.

Protected Attributes

int[] numDiv
 Number of divisions in each dimension, numDiv[j] for coordinate j.
double[] delta
 Size of divisions in each dimension, delta[j] = 1/numDiv[j].
Protected Attributes inherited from umontreal.ssj.hups.PointSet
double EpsilonHalf = 1.0 / Num.TWOEXP[55]
 To avoid 0 for nextCoordinate when random shifting, we add this to each coordinate.
int dim = 0
 Dimension of the points.
int numPoints = 0
 Number of points.
int dimShift = 0
 Current dimension of the shift.
int capacityShift = 0
 Number of array elements in the shift vector, always >= dimShift.
double[] shift
 This is the shift vector as a double[] array, which contains the current random shift in case we apply a random shift modulo 1.
RandomStream shiftStream
 Stream used to generate the random shifts.

Additional Inherited Members

Static Public Member Functions inherited from umontreal.ssj.hups.PointSet
static int getMaxBits ()
 Returns the maximum number of usable bits.
Protected Member Functions inherited from umontreal.ssj.hups.CachedPointSet
void fillCache (int fromDim, int dim)
 Caches the points, skipping fromDim coordinates and taking the next dim ones.
Static Protected Attributes inherited from umontreal.ssj.hups.PointSet
static final int MAXBITS = 31
 Since Java has no unsigned type, the 32nd bit cannot be used efficiently, so we have only 31 bits.
Package Functions inherited from umontreal.ssj.hups.CachedPointSet
public< T > void sort (MultiDimSort< T > sort)
 Sorts the cached points (only) with the given.

Detailed Description

This class implements a stratification of the unit cube in rectangular boxes of same size and orientation.

In \(s\) dimensions, it divides the

\(j\)th axis in \(k_j \ge1\) equal parts of length \(d_j = 1/k_j\), for \(j=0,…,s-1\). This partitions the unit cube \([0,1)^s\) into \(n = k_0\cdots k_{s-1}\) rectangular boxes of the same size. The point set is defined by generating one random point uniformly in each of those \(n\) boxes.

    We number the boxes (or strata) as follows: The box determined by the
    interval @f$[c_j d_j, (c_j+1)d_j)@f$ for @f$j=0,…,s-1@f$ has
    number @f$i = c_0 + c_1 k_0 + \cdots+ c_{s-1} k_0 \cdots k_{s-2}@f$.
    By default, the points are enumerated by order of their box number.
    One can also create iterators that enumerate the points by order of
    any given coordinate.

    Although this class extends `CachedPointSet`, here there is no
    underlying point set `p` that is cached.

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Definition at line 51 of file StratifiedUnitCube.java.

Constructor & Destructor Documentation

◆ StratifiedUnitCube() [1/2]

umontreal.ssj.hups.StratifiedUnitCube.StratifiedUnitCube ( int[] k,
int dim )

Builds a stratified points set in dim dimensions, with k[j] intervals in dimension j.

Parameters
knumber of intervals in each dimension
diminteger, dimension of the points set

Definition at line 70 of file StratifiedUnitCube.java.

◆ StratifiedUnitCube() [2/2]

umontreal.ssj.hups.StratifiedUnitCube.StratifiedUnitCube ( int k,
int dim )

Same as StratifiedUnitCube (int[] k, int dim) with all coordinates of the vector k equal to the integer k.

This gives \(n = k^s\) strata (and points), with

\(s = {\mathtt{dim}}\).

Definition at line 90 of file StratifiedUnitCube.java.

Member Function Documentation

◆ addRandomShift()

void umontreal.ssj.hups.StratifiedUnitCube.addRandomShift ( int fromDim,
int toDim,
RandomStream stream )

Random shifts and partial randomizations are irrelevant here, so this method is redefined to be equivalent to randomize (stream).

The parameters fromDim and toDim are not used.

Reimplemented from umontreal.ssj.hups.CachedPointSet.

Definition at line 136 of file StratifiedUnitCube.java.

◆ randomize() [1/2]

void umontreal.ssj.hups.StratifiedUnitCube.randomize ( PointSetRandomization rand)

Randomizes the points using stratification, regardless of what rand is.

Equivalent to randomize (rand.getStream).

Reimplemented from umontreal.ssj.hups.CachedPointSet.

Definition at line 144 of file StratifiedUnitCube.java.

◆ randomize() [2/2]

void umontreal.ssj.hups.StratifiedUnitCube.randomize ( RandomStream stream)

This randomization generates one point randomly in its corresponding box, for each of the \(n\) boxes.

The stratified points are defined only after this method has been called.

Parameters
streamRandom stream to generate the \(n\times{\mathtt{dim}}\) uniforms required to randomize the points

Definition at line 111 of file StratifiedUnitCube.java.

◆ toString()

String umontreal.ssj.hups.StratifiedUnitCube.toString ( )

Formats a string that contains information about the point set.

Returns
string representation of the point set information

Reimplemented from umontreal.ssj.hups.CachedPointSet.

Definition at line 148 of file StratifiedUnitCube.java.

Member Data Documentation

◆ delta

double [] umontreal.ssj.hups.StratifiedUnitCube.delta
protected

Size of divisions in each dimension, delta[j] = 1/numDiv[j].

Definition at line 61 of file StratifiedUnitCube.java.

◆ numDiv

int [] umontreal.ssj.hups.StratifiedUnitCube.numDiv
protected

Number of divisions in each dimension, numDiv[j] for coordinate j.

Definition at line 56 of file StratifiedUnitCube.java.


The documentation for this class was generated from the following file: