Class RandomRegularGraphGenerator<V,​E>

  • Type Parameters:
    V - graph node type
    E - graph edge type
    All Implemented Interfaces:
    GraphGenerator<V,​E,​V>

    public class RandomRegularGraphGenerator<V,​E>
    extends java.lang.Object
    implements GraphGenerator<V,​E,​V>
    Generate a random $d$-regular undirected graph with $n$ vertices. A regular graph is a graph where each vertex has the same degree, i.e. the same number of neighbors.

    The algorithm for the simple case, proposed in [SW99] and extending the one for the non-simple case [W99], runs in expected $\mathcal{O}(nd^2)$ time. It has been proved in [KV03] to sample from the space of random d-regular graphs in a way which is asymptotically uniform at random when $d = \mathcal{O}(n^{1/3 - \epsilon})$.

    [KV03] Kim, Jeong Han, and Van H. Vu. "Generating random regular graphs." Proceedings of the thirty-fifth annual ACM symposium on Theory of computing. ACM, 2003. [SW99] Steger, Angelika, and Nicholas C. Wormald. "Generating random regular graphs quickly." Combinatorics, Probability and Computing 8.4 (1999): 377-396. [W99] Wormald, Nicholas C. "Models of random regular graphs." London Mathematical Society Lecture Note Series (1999): 239-298.

    Author:
    Emilio Cruciani
    • Constructor Detail

      • RandomRegularGraphGenerator

        public RandomRegularGraphGenerator​(int n,
                                           int d)
        Construct a new RandomRegularGraphGenerator.
        Parameters:
        n - number of nodes
        d - degree of nodes
        Throws:
        java.lang.IllegalArgumentException - if number of nodes is negative
        java.lang.IllegalArgumentException - if degree is negative
        java.lang.IllegalArgumentException - if degree is greater than number of nodes
        java.lang.IllegalArgumentException - if the value "n * d" is odd
      • RandomRegularGraphGenerator

        public RandomRegularGraphGenerator​(int n,
                                           int d,
                                           long seed)
        Construct a new RandomRegularGraphGenerator.
        Parameters:
        n - number of nodes
        d - degree of nodes
        seed - seed for the random number generator
        Throws:
        java.lang.IllegalArgumentException - if number of nodes is negative
        java.lang.IllegalArgumentException - if degree is negative
        java.lang.IllegalArgumentException - if degree is greater than number of nodes
        java.lang.IllegalArgumentException - if the value "n * d" is odd
      • RandomRegularGraphGenerator

        public RandomRegularGraphGenerator​(int n,
                                           int d,
                                           java.util.Random rng)
        Construct a new RandomRegularGraphGenerator.
        Parameters:
        n - number of nodes
        d - degree of nodes
        rng - the random number generator to use
        Throws:
        java.lang.IllegalArgumentException - if number of nodes is negative
        java.lang.IllegalArgumentException - if degree is negative
        java.lang.IllegalArgumentException - if degree is greater than number of nodes
        java.lang.IllegalArgumentException - if the value "n * d" is odd
    • Method Detail

      • generateGraph

        public void generateGraph​(Graph<V,​E> target,
                                  java.util.Map<java.lang.String,​V> resultMap)
        Generate a random regular graph.
        Specified by:
        generateGraph in interface GraphGenerator<V,​E,​V>
        Parameters:
        target - the target graph
        resultMap - the result map
        Throws:
        java.lang.IllegalArgumentException - if target is not an undirected graph
        java.lang.IllegalArgumentException - if "n == d" and the graph is simple