num_triangles()#

relationalai.std.graphs.Compute
num_triangles(node: Producer | None = None) -> Expression

Compute the number of unique triangles in the graph. A triangle is a set of three nodes x, y, and z such that there is an edge between x and y, y and z, and z and x. If node is not None, the number of unique triangles that node is part of is computed. Must be called in a rule or query context.

Supported Graph Types#

Graph TypeSupportedNotes
DirectedYes
UndirectedYes
WeightedYesWeights are ignored.
UnweightedYes

Parameters#

NameTypeDescription
nodeProducer or NoneA node in the graph. If not None, the number of unique triangles that node is part of is computed. Otherwise, the total number of unique triangles in the graph is computed. Default is None.

Returns#

Returns an Expression object that produces the number of unique triangles in the graph as an integer value, if node is None, or the number of unique triangles that node is part of as an integer value, if node is not None.

Example#

Use .num_triangles() to compute the number of unique triangles in a graph. You access the .num_triangles() method from a Graph object’s .compute attribute:

import relationalai as rai
from relationalai.std import alias
from relationalai.std.graphs import Graph

# Create a model named "socialNetwork" with a Person type.
model = rai.Model("socialNetwork")
Person = model.Type("Person")

# Add some people to the model and connect them with a multi-valued `follows` property.
with model.rule():
    alice = Person.add(name="Alice")
    bob = Person.add(name="Bob")
    charlie = Person.add(name="Charlie")
    diana = Person.add(name="Diana")
    alice.follows.add(bob)
    bob.follows.add(charlie)
    charlie.follows.extend([alice, diana])

# Create a directed graph with Person nodes and edges between followers.
# Note that graphs are directed by default.
graph = Graph(model)
graph.Node.extend(Person)
graph.Edge.extend(Person.follows)

# Compute the number of unique triangles in the graph.
with model.query() as select:
    num_triangles = graph.compute.num_triangles()
    response = select(alias(num_triangles, "num_triangles"))

print(response.results)
# Output:
#    num_triangles
# 0              1

# Compute the number of unique triangles that each node is part of.
with model.query() as select:
    person = Person()
    num_triangles = graph.compute.num_triangles(person)
    response = select(person.name, alias(num_triangles, "num_triangles"))

print(response.results)
# Output:
#       name  num_triangles
# 0    Alice              1
# 1      Bob              1
# 2  Charlie              1
# 3    Diana              0

See Also#