SSSP

SQL function: cugraph_sssp

Compute single-source shortest paths.

Signature

cugraph_sssp(table_name, source_vertex [, src_col, dst_col [, weight_col [, options_json]]])

Allowed argument counts: 2, 4, 5, 6.

Quickstart

SELECT * FROM cugraph_sssp('target_edges', 123)

Positional arguments

Argument	Type	Required	Default	Notes
table_name	Utf8	yes
source_vertex	Int64	yes
src_col	Utf8	no	src
dst_col	Utf8	no	dst
weight_col	Utf8|null	no		optional edge weight column for graph construction when supported by the algorithm; semantic effect: edge weights affect algorithm results when provided
options_json	Utf8	no

JSON options

Option	Type	Default	Constraints	Description
cutoff	Float64|null	null	min 0

Graph construction options

Shared by all cuGraph functions, shown here with this function's defaults. The construction_policy option controls whether Nexus requests Python cuGraph-compatible edge normalization or bypasses it for raw libcugraph-style construction; see graph construction options for the full policy guide.

Option	Type	Default	Constraints	Description
construction_policy	Utf8	"python_cugraph"	one of "python_cugraph", "raw_libcugraph"	Edge-list construction semantics used before calling libcugraph.
directed	Boolean	true		Whether graph construction treats edges as directed.
renumber	Boolean	true		Whether graph construction may renumber external vertex identifiers internally.

Output schema

Column	Type	Nullable	Description
vertex	Int64	no	Vertex reached by the shortest-path traversal.
distance	Float64	no	Shortest weighted-path distance from the source vertex.
predecessor	Int64	yes	Previous vertex on the shortest-path tree, null for the source or unreachable vertices.

note

These are the generic registry schemas. Run cugraph_validate_call for the concrete, table-specific output schema of a particular call.

Examples

This example runs on the citation network demo dataset.

SQL-derived edge weights: the time-cost of an idea

The citation edges carry a constant weight, but the weight column handed to SSSP can be computed by SQL. Joining papers on both endpoints prices each citation hop at the number of years it jumps back — so SSSP distance becomes the cumulative "travel through time" along the cheapest reference chain:

CREATE VIEW edges_time_cost AS
SELECT e.src, e.dst,
       CAST(GREATEST(1, ps.year - pd.year) AS DOUBLE) AS weight
FROM citation_edges e
JOIN papers ps ON ps.paper_id = e.src
JOIN papers pd ON pd.paper_id = e.dst
WHERE ps.year > 1900 AND pd.year > 1900;

SELECT CAST(ROUND(s.distance) AS BIGINT) AS time_cost, p.year, p.title
FROM cugraph_sssp('edges_time_cost', 2963403868, 'src', 'dst', 'weight') s
JOIN papers p ON p.paper_id = s.vertex
WHERE s.distance < 1e300
ORDER BY p.year ASC, s.distance ASC
LIMIT 6;

time_cost	year	title
84	1933	Algebraic Functions
82	1935	When is a Trigonometric Polynomial Not a Trigonometric Polynomial
81	1936	Correction to a Note on the Entscheidungsproblem
81	1936	Toward a Calculus of Concepts
81	1936	Set-Theoretic Foundations for Logic
81	1936	A System of Formal Logic without an Analogue to the Curry W. Operator

Starting from Attention Is All You Need (2017), the cheapest reference chains reach the 1936 foundations of computability and formal logic at a time-cost of 81 years. The GREATEST(1, …) clamp keeps weights positive (same-year and forward-dated citations cost 1), and the WHERE clause drops the handful of bogus pre-1900 years in the source data. Unreached vertices report an infinite distance, filtered here with s.distance < 1e300.

Limitations & notes

• dry-run validates table resolution, column presence, static dtypes, and options only
• dry-run does not scan edge data, construct a graph, or prove source-vertex existence

Validate before running

Always dry-run a call before executing it. Validation checks the function, table, columns, dtypes, and options without touching the GPU:

SELECT * FROM cugraph_validate_call(
  'cugraph_sssp',
  'your_edges_table',
  '{"src_col":"src","dst_col":"dst"}'
);

See Discovery & validation for the full cugraph_validate_call contract.