Documentation / Generators

Generator for square grids

This generate square grid graphs of any size with each node not on the border of the graph having four neighbours for regular grids or height neighbours for cross grids. The nodes at each of the four corners of the grid consequently have only two or three (cross) neighbours. The nodes on the side of the grid have three or five (cross) neighbours.

The generated grid can be closed as a torus, meaning that there is no border nodes will exist, therefore all nodes will have the same degree four or height (cross).

Usage

At the contrary of most generators, this generator does not produce only one node when you call nextEvents(). It adds a row and column to the grid, making the side of the square grow by one. Therfore if you call the nextEvents() methode n times you will have n^2 nodes.

You can indicate at construction time if the graph will be a regular grid (no argument) or if it must be a cross-grid (first boolean argument to true) and a tore (second boolean argument to true).

A constructor with a third boolean parameter allows to indicate that nodes must have a xyz attribute to position them or not. This is the default behaviour.

Complexity

At each call to nextEvents() ((n+1)2)* new nodes are generated with n the size of a side of the grid.

Example

Here is an exemple of use:

Graph graph = new SingleGraph("grid");
Generator gen = new GridGenerator();

gen.addSink(graph);
gen.begin();

for(int i=0; i<10; i++) {
	gen.nextEvents();
}

gen.end();

// Nodes already have a position.
graph.display(false);