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GridGraph Class Reference

Detailed Description

GridGraph implements a special graph type. The nodes of the graph can be indexed by two integer values (i,j) where i is in the range [0..width()-1] and j is in the range [0..height()-1]. Two nodes are connected in the graph if the indices differ exactly on one position and the difference is also exactly one. The nodes of the graph can be obtained by position using the operator()() function and the indices of the nodes can be obtained using pos(), col() and row() members. The outgoing arcs can be retrieved with the right(), up(), left() and down() functions, where the bottom-left corner is the origin.

This class is completely static and it needs constant memory space. Thus you can neither add nor delete nodes or edges, however the structure can be resized using resize().

grid_graph.png

A short example about the basic usage:

* GridGraph graph(rows, cols);
* GridGraph::NodeMap<int> val(graph);
* for (int i = 0; i < graph.width(); ++i) {
* for (int j = 0; j < graph.height(); ++j) {
* val[graph(i, j)] = i + j;
* }
* }
*

This type fully conforms to the Graph concept. Most of its member functions and nested classes are documented only in the concept class.

This class provides constant time counting for nodes, edges and arcs.

#include <lemon/grid_graph.h>

Inherits GraphExtender< Base >.

Classes

class  ColMap
 Map to get the column of the nodes. More...
 
class  IndexMap
 Map to get the indices of the nodes as dim2::Point<int>. More...
 
class  RowMap
 Map to get the row of the nodes. More...
 

Public Member Functions

 GridGraph (int width, int height)
 Constructor. More...
 
void resize (int width, int height)
 Resizes the graph. More...
 
Node operator() (int i, int j) const
 The node on the given position. More...
 
int col (Node n) const
 The column index of the node. More...
 
int row (Node n) const
 The row index of the node. More...
 
dim2::Point< int > pos (Node n) const
 The position of the node. More...
 
int width () const
 The number of the columns. More...
 
int height () const
 The number of the rows. More...
 
Arc right (Node n) const
 The arc goes right from the node. More...
 
Arc left (Node n) const
 The arc goes left from the node. More...
 
Arc up (Node n) const
 The arc goes up from the node. More...
 
Arc down (Node n) const
 The arc goes down from the node. More...
 
IndexMap indexMap () const
 Index map of the grid graph. More...
 
RowMap rowMap () const
 Row map of the grid graph. More...
 
ColMap colMap () const
 Column map of the grid graph. More...
 

Constructor & Destructor Documentation

GridGraph ( int  width,
int  height 
)
inline

Construct a grid graph with the given size.

Member Function Documentation

void resize ( int  width,
int  height 
)
inline

This function resizes the graph. It fully destroys and rebuilds the structure, therefore the maps of the graph will be reallocated automatically and the previous values will be lost.

Node operator() ( int  i,
int  j 
) const
inline

Gives back the node on the given position.

int col ( Node  n) const
inline

Gives back the column index of the node.

int row ( Node  n) const
inline

Gives back the row index of the node.

dim2::Point<int> pos ( Node  n) const
inline

Gives back the position of the node, ie. the (col,row) pair.

int width ( ) const
inline

Gives back the number of the columns.

int height ( ) const
inline

Gives back the number of the rows.

Arc right ( Node  n) const
inline

Gives back the arc goes right from the node. If there is not outgoing arc then it gives back INVALID.

Arc left ( Node  n) const
inline

Gives back the arc goes left from the node. If there is not outgoing arc then it gives back INVALID.

Arc up ( Node  n) const
inline

Gives back the arc goes up from the node. If there is not outgoing arc then it gives back INVALID.

Arc down ( Node  n) const
inline

Gives back the arc goes down from the node. If there is not outgoing arc then it gives back INVALID.

IndexMap indexMap ( ) const
inline

Just returns an IndexMap for the grid graph.

RowMap rowMap ( ) const
inline

Just returns a RowMap for the grid graph.

ColMap colMap ( ) const
inline

Just returns a ColMap for the grid graph.