Package com.jgalgo.graph

Interface IndexIntIdMap

  • All Superinterfaces:
    IndexIdMap<Integer>
    public interface IndexIntIdMap
extends IndexIdMap<Integer>
    A mapping between IntGraph IDs to IndexGraph indices.

    This interface is a specific version of IndexIdMap for IntGraph.

    A regular graph contains vertices and edges which are identified by a fixed int IDs. An IndexGraph view is provided by the Graph.indexGraph() method, which is a graph in which all methods are accessed with indices rather than fixed IDs. This interface maps between the indices and the fixed IDs of the graph vertices or edges.

    Note that the mapping may change during the graph lifetime, as vertices and edges are added and removed from the graph, and a regular graph IDs are fixed, while a index graph indices are always (0,1,2, ...,verticesNum-1) and (0,1,2, ...,edgesNum-1). The mapping object will be updated automatically in such cases.

    The mapping interface is used for both vertices and edges, and we use a unify term element in the documentation to describe both of them. If the mapping was obtained by IntGraph.indexGraphVerticesMap() it will map between vertices IDs and indices, and if it was obtained by IntGraph.indexGraphEdgesMap() it will map between edges IDs and indices.

    Author:
    Barak Ugav
    See Also:
    IndexGraph

    • Method Detail

      • indexToIdInt

        int indexToIdInt​(int index)
        Get the ID of an element by its index.

        Whether this method maps vertices or edges depends if the mapping object was obtained by IntGraph.indexGraphVerticesMap() or IntGraph.indexGraphEdgesMap().

        Parameters:
        index - an index of an element (vertex/edge)
        Returns:
        the ID of the element
        Throws:
        IndexOutOfBoundsException - if index is not in range [, elementsNum) where elementsNum is the number of either vertices or edges, depending on the context

      • indexToIdIfExistInt

        int indexToIdIfExistInt​(int index)
        Get the identifier of an element by its index if it exists, or -1 if it doesn't.

        Whether this method maps vertices or edges depends if the mapping object was obtained by Graph.indexGraphVerticesMap() or Graph.indexGraphEdgesMap().

        Parameters:
        index - the index of an element (vertex/edge)
        Returns:
        the identifier of the element, or -1 if there is not such element

      • idToIndex

        int idToIndex​(int id)
        Get the index of an element by its ID.

        Whether this method maps vertices or edges depends if the mapping object was obtained by IntGraph.indexGraphVerticesMap() or IntGraph.indexGraphEdgesMap().

        Parameters:
        id - an ID of an element (vertex/edge)
        Returns:
        the index of the element
        Throws:
        NoSuchVertexException - if this map maps vertices to ids and id is not a valid identifier of a vertex
        NoSuchEdgeException - if this map maps edges to ids and id is not a valid identifier of an edge

      • idToIndexIfExist

        int idToIndexIfExist​(int id)
        Get the index of an element by its identifier if it exists, or -1 if it doesn't.

        Whether this method maps vertices or edges depends if the mapping object was obtained by Graph.indexGraphVerticesMap() or Graph.indexGraphEdgesMap().

        Parameters:
        id - an identifier of an element (vertex/edge)
        Returns:
        the index of the element, or -1 if there is not such element

      • identityVerticesMap

        static IndexIntIdMap identityVerticesMap​(IntSet vertexSet)
        Create an identity mapping between the elements IDs and indices.

        The identity mapping is a mapping in which the ID of an element is equal to its index. This mapping is used by index graphs. The passed set of vertices is expected to be 0,1,2, ..., n-1 where n is the number of vertices in the graph, as only for this set of vertices the identity mapping is possible. The given set is not validated for this condition. The number of vertices, n, is accessible to the mapping by vertexSet.size(), and it is used to determine if an index/id is in range. If the graph is mutable and the mapping should be used during the graph lifetime, the given set should be a view of the graph vertices, so the range checks will be valid.

        Parameters:
        vertexSet - the set of vertices in the graph. The set will be used t
        Returns:
        an identity mapping of the vertices

      • identityEdgesMap

        static IndexIntIdMap identityEdgesMap​(IntSet edgeSet)
        Create an identity mapping between the elements IDs and indices.

        The identity mapping is a mapping in which the ID of an element is equal to its index. This mapping is used by index graphs. The passed set of edges is expected to be 0,1,2, ..., m-1 where m is the number of edges in the graph, as only for this set of edges the identity mapping is possible. The given set is not validated for this condition. The number of edges, m, is accessible to the mapping by edgeSet.size(), and it is used to determine if an index/id is in range. If the graph is mutable and the mapping should be used during the graph lifetime, the given set should be a view of the graph edges, so the range checks will be valid.

        Parameters:
        edgeSet - the set of edges in the graph. The set will be used t
        Returns:
        an identity mapping of the edges