Lodestar.Gpu 0.1.0. This page is frozen at that release. Read the current documentation for what main says now. A link to a decision or a migration page follows main, and leaves the archive.

The signature of every document in a resident batch.

public IReadOnlyList<uint[]> Signatures(DeviceTokenHashes documents, ReadOnlySpan<ulong> multipliers, ReadOnlySpan<ulong> addends)

Parameters — documents is the resident token hashes. multipliers holds the a coefficient of each permutation and addends the b, one per multiplier.

Returns — one signature per document, each as long as there are permutations.

Exceptions — ArgumentNullException when documents is null; ArgumentException when the two coefficient spans are not the same non-zero length.

Example — an empty document gives every slot its maximum.

using Lodestar.Gpu.Compute;

using var context = GpuContext.Create(preferCpu: true);
using var resident = DeviceTokenHashes.Upload(context, [[]]);

IReadOnlyList<uint[]> signatures =
    new TiledMinHashSignatures(context).Signatures(resident, [3UL], [13UL]);

bool atMaximum = signatures[0][0] == uint.MaxValue;  // => True

Remarks — that maximum is the identity a minimum starts from, not a sentinel, so two empty documents estimate a similarity of 1 — exactly as they do on the CPU path. A caller who wants an empty document to match nothing has to check for it before comparing.

The coefficients are uploaded per call and the batch is not, which is the same division every kernel here makes: the small operand travels, the corpus stays. With 128 permutations that upload is two kilobytes against a corpus of any size.

Signatures come back as one array per document rather than one flat block, because what a caller does next is compare two of them — and MinHash.Jaccard takes two spans.

Applies to — net10.0, netstandard2.1.

See also — TiledMinHashSignatures.