hilbert-bytes project

hilbert_bytes module

Hilbert bytes.

Hilbert Bytes is a python library for converting to and from points in d-dimensions and their corresponding index on a hilbert curve. It’s similar to hilbertcurve and numpy-hilbert-curve but is faster and more space efficient than either by keeping manipulations at the byte level, and using numba to compile the results. It also uses arbitrary precision integers, allowing you to make the grid arbitrarily fine.

Use encode and decode to convert between the spaces.

hilbert_bytes.decode(indices: NDArray[uint8], ndim: int) → NDArray[uint8]

Decode dp-byte indices into d-dimensional points.

This function takes indices on the hilbert curve, and the output dimension and converts them to their corresponding points. All numbers are represented as arbitrary precision integers in big-endian form.

ndim must divide the last dimension. If it doesn’t this will error. You may want to treat the input as a smaller number in a higher dimensional space, in which case you just need to prefix with correct number of zero bytes so that ndim does divide.

Example

If you want to use this with native multi-byte integers, you can first cast them to a big-endian variant, then view it as bytes.

indices = ...
index_bytes = indices[..., None].astype(">u8").view("u1")
res = hilbert_bytes.decode(index_bytes, 2)
Parameters:

  • indices ((n, dp)) – A collection of n indices stored as dp-byte big-endian unsigned integers.

  • ndim (d) – The dimension of points to decode into. It must divide dp, but you can always zero pad the left of indices.

Returns:

points – A collection of n d-dimensional points that correspond to the indices along the hilbert-curve.

Return type:

(n, d, p)

Raises:

  • TypeError – If indices isn’t a uint8 array, or ndim isn’t an integer.

  • ValueError – If indices doesn’t have two dimensions, or ndim isn’t positive or doesn’t divide dp.

hilbert_bytes.encode(points: NDArray[uint8]) → NDArray[uint8]

Encode d-dimensional points into their indices on a hilbert curve.

This function takes points in a d-dimensional space, and converts them to their index on the hilbert curve. All numbers are represented as arbitrary precision integers in big-endian form.

Example

If you want to use this with native multi-byte integers, you can first cast them to a big-endian variant, then view it as bytes.

points = ...
point_bytes = points[..., None].astype(">u8").view("u1")
res = hilbert_bytes.encode(point_bytes)
Parameters:

points ((n, d, p)) – A collection of n, d-dimensional points stored as p-byte big-endian unsigned integers.

Returns:

indices – A collection of n big-endian unsigned integers that correspond to the index along the hilbert-curve for the input points.

Return type:

(n, dp)

Raises:

  • TypeError – If points isn’t a uint8 array.

  • ValueError – If points doesn’t have three dimensions.

Indices and tables