com.google.uzaygezen.core

Class CompactHilbertCurve

java.lang.Object

com.google.uzaygezen.core.CompactHilbertCurve

All Implemented Interfaces:

IndexCalculator, SpaceFillingCurve

public class CompactHilbertCurve
extends Object
implements SpaceFillingCurve

Compact Hilbert curve implementation that uses the minimum number of bits needed to establish a bijection between the multidimensional space and the compact Hilbert index, that is, sum(i=0..n-1, m[i]).

The main difference from the paper(s) is that we reverse the order of the dimensions so that we keep the natural orientation of the curve.

This class is not thread safe.

Author:

Daniel Aioanei

Constructor Summary

Constructors

Constructor and Description
CompactHilbertCurve(int[] m) Convenience constructor.
CompactHilbertCurve(MultiDimensionalSpec spec)

Method Summary

Methods

Modifier and Type	Method and Description
void	accept(ZoomingNavigator visitor) Shows the space to the visitor, and the process is guided by the visitor through its boolean returning method.
MultiDimensionalSpec	getSpec() Provides the specification of the multidimensional space on which this space filling curve operates.
void	index(BitVector[] p, int minLevel, BitVector index) Computes the compact Hilbert index of the n-point p.
void	indexInverse(BitVector index, BitVector[] p) Computes the unique n-point p having index as its compact Hilbert index in this multidimensional space.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

CompactHilbertCurve

public CompactHilbertCurve(MultiDimensionalSpec spec)

CompactHilbertCurve

public CompactHilbertCurve(int[] m)

Convenience constructor.

Parameters:

m - bits per dimension

Method Detail

getSpec

public MultiDimensionalSpec getSpec()

Description copied from interface: IndexCalculator

Provides the specification of the multidimensional space on which this space filling curve operates.

Specified by:

getSpec in interface IndexCalculator

Returns:

information about the dimensionality of the space

index

public void index(BitVector[] p,
         int minLevel,
         BitVector index)

Computes the compact Hilbert index of the n-point p.

Specified by:

index in interface IndexCalculator

Parameters:

p - point in the multidimensional space. Implementations are not allowed to modify anything in this parameter.

minLevel - the level between 0 and mMax inclusive, inclusive, up to which the index bits should be calculated. If equal to mMax, then the result is always zero since there are no dimensions that have the mMax bit. To get the full compact index specify minLevel = 0.

index - output

indexInverse

public void indexInverse(BitVector index,
                BitVector[] p)

Computes the unique n-point p having index as its compact Hilbert index in this multidimensional space.

Specified by:

indexInverse in interface SpaceFillingCurve

Parameters:

index - the index of a to-be-located point. Implementations must not modify this parameter in any way.

p - output

accept

public void accept(ZoomingNavigator visitor)

Description copied from interface: SpaceFillingCurve

Shows the space to the visitor, and the process is guided by the visitor through its boolean returning method. Thus the visitor has a double role as a driver of the navigation since at each call it decides if it wants to zoom in or not. The visitor is guaranteed to see the space in index order in-depth traversal.

Specified by:

accept in interface SpaceFillingCurve

Parameters:

visitor - driver-visitor

toString

public String toString()

Overrides:

toString in class Object