org.graphstream.algorithm.generator
Class GridGenerator

java.lang.Object
  org.graphstream.stream.SourceBase
      org.graphstream.algorithm.generator.BaseGenerator
          org.graphstream.algorithm.generator.GridGenerator

All Implemented Interfaces:

Generator, org.graphstream.stream.Source

public class GridGenerator
extends BaseGenerator

Generator for square grids of any size.

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

 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);
 

Since:

2007

Nested Class Summary

Nested classes/interfaces inherited from class org.graphstream.stream.SourceBase

org.graphstream.stream.SourceBase.ElementType

Constructor Summary

GridGenerator()
New grid generator.

GridGenerator(boolean cross, boolean tore)
New grid generator.

GridGenerator(boolean cross, boolean tore, boolean generateXY)
New grid generator.

GridGenerator(boolean cross, boolean tore, boolean generateXY, boolean directed)
New grid generator.

Method Summary

void	begin() Add an initial node.
void	end() If grid is a tore, a call to this method will close the tore.
boolean	nextEvents() Grow the graph.

Methods inherited from class org.graphstream.algorithm.generator.BaseGenerator

addEdgeAttribute, addEdgeLabels, addNodeAttribute, addNodeLabels, isUsingInternalGraph, removeEdgeAttribute, removeNodeAttribute, setDirectedEdges, setEdgeAttributesRange, setNodeAttributesRange, setRandomSeed, setUseInternalGraph

Methods inherited from class org.graphstream.stream.SourceBase

addAttributeSink, addElementSink, addSink, attributeSinks, clearAttributeSinks, clearElementSinks, clearSinks, elementSinks, removeAttributeSink, removeElementSink, removeSink, sendAttributeChangedEvent, sendAttributeChangedEvent, sendEdgeAdded, sendEdgeAdded, sendEdgeAttributeAdded, sendEdgeAttributeAdded, sendEdgeAttributeChanged, sendEdgeAttributeChanged, sendEdgeAttributeRemoved, sendEdgeAttributeRemoved, sendEdgeRemoved, sendEdgeRemoved, sendGraphAttributeAdded, sendGraphAttributeAdded, sendGraphAttributeChanged, sendGraphAttributeChanged, sendGraphAttributeRemoved, sendGraphAttributeRemoved, sendGraphCleared, sendGraphCleared, sendNodeAdded, sendNodeAdded, sendNodeAttributeAdded, sendNodeAttributeAdded, sendNodeAttributeChanged, sendNodeAttributeChanged, sendNodeAttributeRemoved, sendNodeAttributeRemoved, sendNodeRemoved, sendNodeRemoved, sendStepBegins, sendStepBegins

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.graphstream.stream.Source

addAttributeSink, addElementSink, addSink, clearAttributeSinks, clearElementSinks, clearSinks, removeAttributeSink, removeElementSink, removeSink

Constructor Detail

GridGenerator

public GridGenerator()

New grid generator. By default no diagonal links are made and the grid is not a tore.

GridGenerator

public GridGenerator(boolean cross,
                     boolean tore)

New grid generator.

Parameters:

cross - Create diagonal links?.

tore - Close the grid as a tore?.

GridGenerator

public GridGenerator(boolean cross,
                     boolean tore,
                     boolean generateXY)

New grid generator.

Parameters:

cross - Create diagonal links?

tore - Close the grid as a tore?

generateXY - Generate coordinates of nodes.

GridGenerator

public GridGenerator(boolean cross,
                     boolean tore,
                     boolean generateXY,
                     boolean directed)

New grid generator.

Parameters:

cross - Create diagonal links ?

tore - Close the grid as a tore ?

generateXY - Generate coordinates of nodes.

directed - Are edges directed ?

Method Detail

begin

public void begin()

Add an initial node.

See Also:

Generator.begin()

nextEvents

public boolean nextEvents()

Grow the graph. If grid dimensions are width x height, then after a call to this method dimensions will be (width+1)x(height+1).

Returns:

true while there are elements to add to the graph.

See Also:

Generator.nextEvents()

end

public void end()

If grid is a tore, a call to this method will close the tore.

Specified by:

end in interface Generator

Overrides:

end in class BaseGenerator

See Also:

Generator.end()