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Graph Analytics and Pre‑Defined Functions in Vadalog

Why graph analytics inside a reasoning language?​

Many real‑world knowledge‑management tasks (supply‑chain optimisation, fraud detection, recommendation, etc.) are both graph‑shaped and rule‑driven.
Vadalog lets you run industrial‑strength graph algorithms and logical reasoning in the same declarative program.
Execution is automatically parallel and distributed.

Using Graph Functions​

A graph algorithm appears as a function literal that starts with # and lives in a rule body:

tc_function(X,Y)  :-  #TC(edge).          % transitive closure on edge/2
asp_function(X,Y,Z) :-  #ASP(edge).         % all‑shortest paths on weighted edge/3

Variables on the head of the rule with the function receive the algorithm’s results.

Built‑in graph function catalogue​

FunctionProblem solvedInput predicate (arity)Output variablesNotes
#TC(P)Transitive Closure – reachability.P/2 edge(U,V)(X,Y)Directed graph. No duplicates.
#ASP(P)All‑Shortest Paths (weighted).P/3 edge(U,V,W)(X,Y,Z)Parallel multi‑source Dijkstra.
#SSSP(P,Src)Single‑Source Shortest Path.same as #ASP plus constant Src(Y,Dist)
#BFS(P)Breadth‑First Levels.P/2(X,Level)Unweighted tiers.
#PR(P[,d])PageRank scores.P/2(X,Score)Optional damping d (default 0.85).
#CC(P)Connected Components (undirected).P/2(X,Comp)
#WCC(P)Weakly Connected Components.P/2(X,Comp)Treats edges as undirected.
#TRI(P)Triangle Enumeration.P/2(X,Y,Z)Unordered triangles.
#BC(P)Betweenness Centrality (approx.).P/2(X,Score)Brandes with sampling.

Examples​

1  Transitive closure​

edge(1,2).
edge(2,3).
edge(3,4).
edge(4,1).

tc_function(X,Y) :- #TC(edge).
@output("tc_function").

2  All shortest paths​

edge(1,2,9).
edge(2,3,5).
edge(3,4,6).
edge(4,1,8).

asp_function(X,Y) :- #ASP(edge).
@output("asp_function").

Reasoning + Graph Analytics​

edge_large(1,2,9).
edge_large(3,4,6).

edge_short(2,3,2).
edge_short(4,1,1).

unweighted_edge(1,5).
unweighted_edge(5,2).

edge(X,Y,Z) :- edge_large(X,Y,Z).
edge(X,Y,Z) :- edge_short(X,Y,Z).
edge(X,Y,1) :- unweighted_edge(X,Y). % We assign a default distance = 1

asp_function(X,Y,Z) :- #ASP(edge).
max_asp(X,Y,M) :- asp_function(X,Y,Z), M = mmax(Z).
@output("max_asp").
highly_connected(Z) :-
      vertex(Z),
      #PR(edge)(Z,Score),
      Score > 0.02.

@output("highly_connected").