org.davidmoten.hilbert

Class HilbertCurve

java.lang.Object

org.davidmoten.hilbert.HilbertCurve

public final class HilbertCurve
extends Object

Converts between Hilbert index (BigInteger) and N-dimensional points.

Note: This algorithm is derived from work done by John Skilling and published in "Programming the Hilbert curve". (c) 2004 American Institute of Physics. With thanks also to Paul Chernoch who published a C# algorithm for Skilling's work on StackOverflow and GitHub).

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	HilbertCurve.Builder Builds a HilbertCurve instance.

Method Summary

Modifier and Type	Method and Description
static HilbertCurve.Builder	bits(int bits) Returns a builder for and object that performs transformations for a Hilbert curve with the given number of bits.
BigInteger	index(long... point) Converts a point to its Hilbert curve index.
long[]	point(BigInteger index) Converts a BigInteger index (distance along the Hilbert Curve from 0) to a point of dimensions defined in the constructor of this.
long[]	point(long index) Converts a long index (distance along the Hilbert Curve from 0) to a point of dimensions defined in the constructor of this.
static SmallHilbertCurve.Builder	small()

Methods inherited from class java.lang.Object

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

Method Detail

bits

public static HilbertCurve.Builder bits(int bits)

Returns a builder for and object that performs transformations for a Hilbert curve with the given number of bits.

Parameters:

bits - depth of the Hilbert curve. If bits is one, this is the top-level Hilbert curve

Returns:

builder for object to do transformations with the Hilbert Curve

small

public static SmallHilbertCurve.Builder small()

index

public BigInteger index(long... point)

Converts a point to its Hilbert curve index.

Parameters:

point - an array of long. Each coordinate can be between 0 and 2^bits-1.

Returns:

index (nonnegative BigInteger)

Throws:

IllegalArgumentException - if length of point array is not equal to the number of dimensions.

point

public long[] point(BigInteger index)

Converts a BigInteger index (distance along the Hilbert Curve from 0) to a point of dimensions defined in the constructor of this.

Parameters:

index - index along the Hilbert Curve from 0. Maximum value 2 ^{bits * dimensions}-1.

Returns:

array of longs being the point

Throws:

NullPointerException - if index is null

IllegalArgumentException - if index is negative

point

public long[] point(long index)

Converts a long index (distance along the Hilbert Curve from 0) to a point of dimensions defined in the constructor of this.

Parameters:

index - index along the Hilbert Curve from 0. Maximum value 2 ^bits+1-1.

Returns:

array of longs being the point

Throws:

IllegalArgumentException - if index is negative