/ 
Path-Hilbert-1
River stage zero No dependents
/ Path::Hilbert

NAME

Path::Hilbert - A no-frills converter between 1D and 2D spaces using the Hilbert curve

SYNOPSIS

use Path::Hilbert;
my ($x, $y) = d2xy(16, 127);
my $d = xy2d(16, $x, $y);
die unless $d == 127;

my $space = Path::Hilbert->new(16);
my ($u, $v) = $space->d2xy(127);
my $t = $space->xy2d($u, $v);
die unless $t == 127;

Description

See Wikipedia for a description of the Hilbert curve, and why it's a good idea.

Most (all?) of the existing CPAN modules for dealing with Hilbert curves state "only works for $foo data", "optimized for foo situations", or "designed to work as part of the foo framework". This module is based directly on the example algorithm given on Wikipedia, and thus is subject only to the single strict limitation of Hilbert curves: that the side-length 'n' MUST be an integer power of 2.

Function-Oriented Interface

($X, $Y) = d2xy($SIDE, $INDEX)

Returns the X and Y coordinates (each in the range 0 .. n - 1) of the supplied INDEX (in the range 0 .. SIDE ** 2 - 1), where SIDE itself is an integer power of 2.

$INDEX = xy2d($SIDE, $X, $Y)

Returns the INDEX (in the range 0 .. SIDE ** 2 - 1) of the point corresponding to the supplied X and Y coordinates (each in the range 0 .. n - 1), where SIDE itself is an integer power of 2.

Object-Oriented Interface

$object = Path::Hilbert->new(SIDE)

Create a new Path::Hilbert object with the specified SIDE (which must be an integer power of 2).

($X, $Y) = $object->d2xy($INDEX)

Returns the X and Y coordinates (each in the range 0 .. n - 1) of the supplied INDEX (in the range 0 .. SIDE ** 2 - 1), where SIDE was provided via new().

$INDEX = $object->xy2d($X, $Y)

Returns the INDEX (in the range 0 .. SIDE ** 2 - 1) of the point corresponding to the supplied X and Y coordinates (each in the range 0 .. n - 1), where SIDE was provided via new().

BUGS

Please let me know via the CPAN RT if you find any algorithmic defects. I'm well aware that there are a number of opportunities to speed it up.

TODO

Speed it up. XS? Memoization?

AUTHOR

PWBENNETT <paul.w.bennett@gmail.com>

LICENSE

Same as Perl.