- cugraph.ktruss_subgraph(G: Union[Graph, networkx.Graph], k: int, use_weights=True) Graph #
Returns the K-Truss subgraph of a graph for a specific k.
NOTE: this function is currently not available on CUDA 11.4 systems.
The k-truss of a graph is a subgraph where each edge is part of at least (k−2) triangles. K-trusses are used for finding tighlty knit groups of vertices in a graph. A k-truss is a relaxation of a k-clique in the graph and was define in . Finding cliques is computationally demanding and finding the maximal k-clique is known to be NP-Hard.
In contrast, finding a k-truss is computationally tractable as its key building block, namely triangle counting, can be executed in polnymomial time.Typically, it takes many iterations of triangle counting to find the k-truss of a graph. Yet these iterations operate on a weakly monotonically shrinking graph. Therefore, finding the k-truss of a graph can be done in a fairly reasonable amount of time. The solution in cuGraph is based on a GPU algorithm first shown in  and uses the triangle counting algorithm from .
cuGraph graph descriptor with connectivity information. k-Trusses are defined for only undirected graphs as they are defined for undirected triangle in a graph. The current implementation only supports undirected graphs.
The desired k to be used for extracting the k-truss subgraph.
- use_weightsbool, optional (default=True)
Whether the output should contain the edge weights if G has them.
Deprecated: If ‘weights’ were passed at the graph creation, they will be used.
A cugraph graph descriptor with the k-truss subgraph for the given k.
 Cohen, J., “Trusses: Cohesive subgraphs for social network analysis” National security agency technical report, 2008
 O. Green, J. Fox, E. Kim, F. Busato, et al. “Quickly Finding a Truss in a Haystack” IEEE High Performance Extreme Computing Conference (HPEC), 2017 https://doi.org/10.1109/HPEC.2017.8091038
 O. Green, P. Yalamanchili, L.M. Munguia, “Fast Triangle Counting on GPU” Irregular Applications: Architectures and Algorithms (IA3), 2014
>>> from cugraph.datasets import karate >>> G = karate.get_graph(download=True) >>> k_subgraph = cugraph.ktruss_subgraph(G, 3)