Overlap

SQL function: cugraph_overlap

Official cuGraph reference: C API

Compare explicit vertex pairs by dividing their shared-neighbor count by the smaller of their two neighbor counts.

Quickstart

The call below supplies edges from registered relation target_edges with canonical src and dst columns and may include weight, plus the registered relation candidate_pairs (the vertex_pairs relation with columns first, second). Substitute your own registered relations.

SELECT * FROM cugraph_overlap(edges => (SELECT src, dst FROM target_edges), vertex_pairs => (SELECT first, second FROM candidate_pairs));

Inputs

Every relation is a named parenthesized SELECT subquery. The required edges role uses canonical src and dst columns; every role, its canonical columns, and their accepted Arrow types are listed under Relation arguments. Metadata validation resolves registered tables named in its JSON request.

Endpoint columns accept numeric Int32, Int64 vertex IDs or logical string Utf8, LargeUtf8, Utf8View vertex IDs; string vertex-identity outputs are canonicalized to Utf8 (native mapping Int64) while scores, distances, counts, coordinates, and opaque labels stay numeric. The shared vertex-ID contract is summarized in Vertex ID support; the concrete call-specific schema comes from gpu_validate_call.

Logical string side-input limitations:

• edge ID columns and edge-ID predicate side inputs are not supported for logical string graphs
• candidate-pair columns must match the graph vertex domain; logical string graphs accept Utf8, LargeUtf8, or Utf8View independently per column

Arguments and options

Relation arguments

Argument	Required	Columns	Description
edges	yes	src, dst: Int32, Int64, Utf8, LargeUtf8, Utf8View weight (optional): Float32, Float64 edge_id (optional): Int32, Int64	edge relation with canonical src and dst columns, plus optional weight and edge_id columns
vertex_pairs	yes	first, second: Int32, Int64, Utf8, LargeUtf8, Utf8View	explicit vertex pairs used by similarity scoring

Vertex columns of vertex_pairs must use the same vertex domain as edges: the integer type of src and dst, or any listed string type when the endpoints are strings. Every edge_id column must have the integer type of src and dst; string-keyed graphs accept no edge IDs.

Named value arguments

This function has no algorithm-specific value arguments. Its inputs are the relation arguments above and the graph construction options below.

Graph construction options

This function requires directed=false (undirected/symmetric graph); all other graph construction options follow the shared defaults documented in Graph Construction Options.

Output

Column	Type	Nullable	Description
first	Int64|Utf8	no	First vertex from the explicit candidate-pair relation.
second	Int64|Utf8	no	Second vertex from the explicit candidate-pair relation.
similarity	Float64	no	Similarity coefficient for the explicit candidate pair.

These are generic descriptor schemas; run gpu_validate_call to get the concrete, table-specific output schema.

Examples

Canonical call shape using target_edges as the edge table:

SELECT * FROM cugraph_overlap(
  edges => (SELECT src, dst FROM target_edges),
  vertex_pairs => (SELECT first, second FROM candidate_pairs))

Use the same shape with your registered relations; pass algorithm and graph values as additional named arguments, for example directed => false or construction_policy => 'raw_libcugraph'.

Limits

• similarity is explicit-pair only; all-pairs candidate generation and all-pairs top-k search are not exposed
• vertex_pairs is a required relation with canonical first and second columns
• candidate-pair columns must match the graph vertex domain; logical string graphs accept Utf8, LargeUtf8, or Utf8View independently per column
• null candidate-pair values are rejected at execution and are never dropped
• candidate pairs are a multiset: duplicate, reversed, and self pairs remain distinct output rows
• result rows have no global ordering; use ORDER BY when order is required
• providing edges.weight selects weighted similarity; omitting it selects unit-weight similarity
• cuGraph requires directed=false so the graph is constructed as an undirected/symmetric view

To dry-run validate relation metadata, column types, and options without execution, see gpu_validate_call.