layout.drl {igraph} | R Documentation

## The DrL graph layout generator

### Description

DrL is a force-directed graph layout toolbox focused on real-world large-scale graphs, developed by Shawn Martin and colleagues at Sandia National Laboratories.

### Usage

    layout.drl (graph, use.seed = FALSE, seed = matrix(runif(vcount(graph) *
        2), nc = 2), options = igraph.drl.default, weights = E(graph)$weight,
        fixed = NULL, dim = 2)

### Arguments

`graph` | The input graph, in can be directed or undirected.
`use.seed` | Logical scalar, whether to use the coordinates given in the `seed` argument as a starting point.
`seed` | A matrix with two columns, the starting coordinates for the vertices is `use.seed` is `TRUE`. It is ignored otherwise.
`options` | Options for the layout generator, a named list. See details below.
`weights` | Optional edge weights. Supply `NULL` here if you want to weight edges equally. By default the `weight` edge attribute is used if the graph has one.
`fixed` | Logical vector, it can be used to fix some vertices. All vertices for which it is `TRUE` are kept at the coordinates supplied in the `seed` matrix. It is ignored it `NULL` or if `use.seed` is `FALSE`.
`dim` | Either ‘2’ or ‘3’, it specifies whether we want a two dimensional or a three dimensional layout. Note that because of the nature of the DrL algorithm, the three dimensional layout takes significantly longer to compute.

### Details

This function implements the force-directed DrL layout generator.

The generator has the following parameters:

edge.cut
  Edge cutting is done in the late stages of the algorithm in order to achieve less dense layouts. Edges are cut if there is a lot of stress on them (a large value in the objective function sum). The edge cutting parameter is a value between 0 and 1 with 0 representing no edge cutting and 1 representing maximal edge cutting.
init.iterations
  Number of iterations in the first phase.
init.temperature
  Start temperature, first phase.
init.attraction
  Attraction, first phase.
init.damping.mult
  Damping, first phase.
liquid.iterations
  Number of iterations, liquid phase.
liquid.temperature
  Start temperature, liquid phase.
liquid.attraction
  Attraction, liquid phase.
liquid.damping.mult
  Damping, liquid phase.
expansion.iterations
  Number of iterations, expansion phase.
expansion.temperature
  Start temperature, expansion phase.
expansion.attraction
  Attraction, expansion phase.
expansion.damping.mult
  Damping, expansion phase.
cooldown.iterations
  Number of iterations, cooldown phase.
cooldown.temperature
  Start temperature, cooldown phase.
cooldown.attraction
  Attraction, cooldown phase.
cooldown.damping.mult
  Damping, cooldown phase.
crunch.iterations
  Number of iterations, crunch phase.
crunch.temperature
  Start temperature, crunch phase.
crunch.attraction
  Attraction, crunch phase.
crunch.damping.mult
  Damping, crunch phase.
simmer.iterations
  Number of iterations, simmer phase.
simmer.temperature
  Start temperature, simmer phase.
simmer.attraction
  Attraction, simmer phase.
simmer.damping.mult
  Damping, simmer phase.

There are five pre-defined parameter settings as well, these are called `igraph.drl.default`, `igraph.drl.coarsen`, `igraph.drl.coarsest`, `igraph.drl.refine` and `igraph.drl.final`.

### Value

A numeric matrix with two columns.

### Author(s)

Shawn Martin google@for.it and Gabor Csardi csardi@rmki.kfki.hu for the R/igraph interface and the three dimensional version.

### References

http://www.cs.sandia.gov/~smartin/software.html

### See Also

`layout` for other layout generators.

### Examples

    g <- as.undirected(ba.game(100, m=1))
    l <- layout.drl(g, options=list(simmer.attraction=0))
    ## Not run:
    plot(g, layout=l, vertex.size=3, vertex.label=NA)
    ## End(Not run)

[Package igraph version 0.5.2 Index]