# R igraph manual pages

Use this if you are using igraph from R

## The Fruchterman-Reingold layout algorithm

### Description

Place vertices on the plane using the force-directed layout algorithm by Fruchterman and Reingold.

### Usage

layout_with_fr(
graph,
coords = NULL,
dim = 2,
niter = 500,
start.temp = sqrt(vcount(graph)),
grid = c("auto", "grid", "nogrid"),
weights = NULL,
minx = NULL,
maxx = NULL,
miny = NULL,
maxy = NULL,
minz = NULL,
maxz = NULL,
coolexp,
maxdelta,
area,
maxiter
)

with_fr(...)


### Arguments

 graph The graph to lay out. Edge directions are ignored. coords Optional starting positions for the vertices. If this argument is not NULL then it should be an appropriate matrix of starting coordinates. dim Integer scalar, 2 or 3, the dimension of the layout. Two dimensional layouts are places on a plane, three dimensional ones in the 3d space. niter Integer scalar, the number of iterations to perform. start.temp Real scalar, the start temperature. This is the maximum amount of movement alloved along one axis, within one step, for a vertex. Currently it is decreased linearly to zero during the iteration. grid Character scalar, whether to use the faster, but less accurate grid based implementation of the algorithm. By default (“auto”), the grid-based implementation is used if the graph has more than one thousand vertices. weights A vector giving edge weights. The weight edge attribute is used by default, if present. If weights are given, then the attraction along the edges will be multiplied by the given edge weights. This places vertices connected with a highly weighted edge closer to each other. minx If not NULL, then it must be a numeric vector that gives lower boundaries for the ‘x’ coordinates of the vertices. The length of the vector must match the number of vertices in the graph. maxx Similar to minx, but gives the upper boundaries. miny Similar to minx, but gives the lower boundaries of the ‘y’ coordinates. maxy Similar to minx, but gives the upper boundaries of the ‘y’ coordinates. minz Similar to minx, but gives the lower boundaries of the ‘z’ coordinates. maxz Similar to minx, but gives the upper boundaries of the ‘z’ coordinates. coolexp, maxdelta, area, repulserad These arguments are not supported from igraph version 0.8.0 and are ignored (with a warning). maxiter A deprecated synonym of niter, for compatibility. ... Passed to layout_with_fr.

### Details

See the referenced paper below for the details of the algorithm.

This function was rewritten from scratch in igraph version 0.8.0.

### Value

A two- or three-column matrix, each row giving the coordinates of a vertex, according to the ids of the vertex ids.

### Author(s)

Gabor Csardi csardi.gabor@gmail.com

### References

Fruchterman, T.M.J. and Reingold, E.M. (1991). Graph Drawing by Force-directed Placement. Software - Practice and Experience, 21(11):1129-1164.

layout_with_drl, layout_with_kk for other layout algorithms.

Other graph layouts: add_layout_(), component_wise(), layout_as_bipartite(), layout_as_star(), layout_as_tree(), layout_in_circle(), layout_nicely(), layout_on_grid(), layout_on_sphere(), layout_randomly(), layout_with_dh(), layout_with_gem(), layout_with_graphopt(), layout_with_kk(), layout_with_lgl(), layout_with_mds(), layout_with_sugiyama(), layout_(), merge_coords(), norm_coords(), normalize()

### Examples


# Fixing ego
g <- sample_pa(20, m=2)
minC <- rep(-Inf, vcount(g))
maxC <- rep(Inf, vcount(g))
minC[1] <- maxC[1] <- 0
co <- layout_with_fr(g, minx=minC, maxx=maxC,
miny=minC, maxy=maxC)
co[1,]
plot(g, layout=co, vertex.size=30, edge.arrow.size=0.2,
vertex.label=c("ego", rep("", vcount(g)-1)), rescale=FALSE,
xlim=range(co[,1]), ylim=range(co[,2]), vertex.label.dist=0,
vertex.label.color="red")
axis(1)
axis(2)



[Package igraph version 1.2.5 Index]