next up previous contents index
Next: Edge Maps ( edge_map Up: Graphs and Related Data Previous: Face Arrays ( face_array   Contents   Index


Node Maps ( node_map )

Definition

An instance of the data type node_map<E> is a map for the nodes of a graph G, i.e., equivalent to map<node,E> (cf. Maps). It can be used as a dynamic variant of the data type node_array (cf. Node Arrays). New: Since node_map<E> is derived from node_array<E> node maps can be passed (by reference) to functions with node array parameters. In particular, all LEDA graph algorithms expecting a node_array<E>& argument can be passed a node_map<E> instead.

#include < LEDA/node _map.h >

Creation

node_map<E> M introduces a variable M of type node_map<E> and initializes it to the map with empty domain.

node_map<E> M(graph G) introduces a variable M of type node_map<E> and initializes it with a mapping m from the set of all nodes of G into the set of variables of type E. The variables in the range of m are initialized by a call of the default constructor of type E.

node_map<E> M(graph G, E x) introduces a variable M of type node_map<E> and initializes it with a mapping m from the set of all nodes of G into the set of variables of type E. The variables in the range of m are initialized with a copy of x.

Operations

graph M.get_graph() returns a reference to the graph of M.

void M.init() makes M a node map with empty domain.

void M.init(graph G) makes M a mapping m from the set of all nodes of G into the set of variables of type E. The variables in the range of m are initialized by a call of the default constructor of type E.

void M.init(graph G, E x) makes M a mapping m from the set of all nodes of G into the set of variables of type E. The variables in the range of m are initialized with a copy of x.

E& M[node v] returns the variable M(v).

Implementation

Node maps are implemented by an efficient hashing method based on the internal numbering of the nodes. An access operation takes expected time O(1).


next up previous contents index
Next: Edge Maps ( edge_map Up: Graphs and Related Data Previous: Face Arrays ( face_array   Contents   Index
LEDA research project
2000-02-09