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Face Maps ( face_map )

Definition

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

#include < LEDA/graph/face_map.h >

Creation

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

face_map< E> M(const graph_t& G) introduces a variable M of type face_map<E> and initializes it with a mapping m from the set of all faces 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 .

face_map< E> M(const graph_t& G, E x) introduces a variable M of type face_map<E> and initializes it with a mapping m from the set of all faces 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

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

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

void M.init(const graph_t& G) makes M a mapping m from the set of all faces 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(const graph_t& G, E x)
    makes M a mapping m from the set of all faces 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[face f] returns the variable M(v) .

Implementation

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


next up previous contents index
Next: Two Dimensional Node Arrays Up: Graphs and Related Data Previous: Edge Maps ( edge_map   Contents   Index
Christian Uhrig 2017-04-07