Version 5.0 The LEDA User Manual

11.10 Face Arrays ( face array )
1. Definition
An instance A of the parameterized data type face array is a partial mapping from
the face set of a graph G to the set of variables of type E, called the element type of the
array. The domain I of A is called the index set of A and A(f) is called the element at
position f. A is said to be valid for all faces in I. The array access operator A[f] checks
its precondition (A must be valid for f). The check can be turned off by compiling with
the flag -DLEDA_CHECKING_OFF.
#include < LEDA/graph/face array.h >
2. Creation
face array A;
creates an instance A of type face array with empty index set.
face array A(const graph t& G);
face array A(const graph t& G, E x);
creates an instance A of type face array and initializes the index
set of A to the current face set of graph G.
creates an instance A of type face array, sets the index set of
A to the current face set of graph G and initializes A(f) with x for
all faces f of G.
face array A(const graph t& G, int n, E x);
creates an instance A of type face array valid for up to n faces
of graph G and initializes A(f) with x for all faces f of G.
Precondition: n ≥ |V |.
A is also valid for the next n − |V | faces added to G.
3. Operations
const graph t& A.get graph( ) returns a reference to the graph of A.
E& A[face f] returns the variable A(f).
Precondition: A must be valid for f.
void
A.init(const graph t& G) sets the index set I of A to the face set of G, i.e., makes
A valid for all faces of G.
void A.init(const graph t& G, E x)
makes A valid for all faces of G and sets A(f) = x for
all faces f of G.