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Input Formats

Table Functions

Table functions expect edges as a subquery with two bigint columns:

create table my_edges as select * from (values (1::bigint, 2::bigint), (2, 3)) t(src, dst);

select *
from onager_ctr_pagerank((select src, dst from my_edges));

Named Graphs

Scalar functions operate on named graphs stored in the registry:

select onager_create_graph('social', true);
select onager_add_node('social', 1);
select onager_node_in_degree('social', 1);

Edge list format

Onager uses edge lists, not adjacency matrices. Each row represents one edge with a source and destination node.

Node IDs

Node IDs must be bigint integers. They do not need to be continuous or start from zero. Any integer value works, like 1, 2, 3 or 100, 200, 500.

Directed vs undirected

Most functions treat graphs as undirected by default. Use the directed := true parameter where available to treat edges as one-way.

Weighted functions

Some functions accept edge weights as a third column. These include:

  • onager_pth_bellman_ford — shortest paths with negative weights
  • onager_pth_floyd_warshall — all-pairs shortest paths
  • onager_mst_kruskal — minimum spanning tree
  • onager_apx_tsp — traveling salesman approximation

Pass weights like this: 

create table edges as select * from (values
  (1::bigint, 2::bigint, 1.0::double), (2, 3, 2.0), (3, 4, 1.5)
) t(src, dst, weight);

select * from onager_mst_kruskal((select src, dst, weight from edges));