Definition
An instance of the data type node_map2<E> is a map2 for the pairs of nodes of a graph G, i.e., equivalent to map2<node,node,E> (cf. Two-Dimensional Maps). It can be used as a dynamic variant of the data type node_matrix (cf. Two Dimensional Node Arrays).
Creation
node_map2<E> | M; | introduces a variable M of type node_map2<E> and initializes it to the map2 with empty domain. |
node_map2<E> |
M(graph G); | introduces a variable M of type node_map2<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_map2<E> |
M(graph G, E x); | introduces a variable M of type node_map2<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. |
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Operations
void | M.init() | makes M a node map2 with empty domain. |
void | M.init(graph G) | makes M to 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 to 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, node w) | returns the variable M(v,w). |
bool | M.defined(node v, node w) | returns true if (v,w) in dom(m) and false otherwise. |
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).