layout_gephi_fr: Gephi Fruchterman-Reingold Layout

In cograph: Analysis and Visualization of Complex Networks

Gephi Fruchterman-Reingold Layout

Description

Force-directed layout that replicates Gephi's Fruchterman-Reingold algorithm. This is a strict port of the Java implementation from Gephi's source code, with additional improvements for reproducibility and flexibility.

Usage

layout_gephi_fr(
  g,
  area = 10000,
  gravity = 1,
  speed = 1,
  niter = 100,
  seed = NULL,
  initial = NULL,
  normalize = TRUE,
  gravity_mode = c("linear", "degree", "none"),
  cooling_mode = c("constant", "vcf", "linear"),
  anchor_strength = 0
)

Arguments

g	An igraph graph object.
area	Area parameter controlling node spread. Default 10000.
gravity	Gravity force pulling nodes toward center. Default 1.0. (Note: Reduced from Gephi's default of 10.0 to prevent circular layouts)
speed	Speed/cooling parameter. Default 1.0.
niter	Number of iterations. Default 100.
seed	Random seed for reproducibility. Default NULL.
initial	Optional initial coordinates (matrix or data frame). Useful for warm-starting or animations.
normalize	Logical. If TRUE (default), normalize output to [0,1] range. If FALSE, return raw Gephi-scale coordinates.
gravity_mode	Gravity behavior: "linear" (default, standard gravity), "degree" (high-degree nodes feel stronger gravity, creates hub structure), or "none" (no gravity, like igraph FR).
cooling_mode	Cooling schedule: "constant" (default, no cooling), "vcf" (Variable Cooling Factor - adapts based on movement), or "linear" (linear decrease over iterations).
anchor_strength	Strength of force pulling nodes toward initial positions (default: 0). Only applies when initial is provided.

Details

This layout is a direct port of Gephi's ForceAtlas algorithm variant of Fruchterman-Reingold. Key differences from igraph's layout_with_fr:

• Uses Gephi's specific constants (SPEED_DIVISOR=800, AREA_MULTIPLICATOR=10000)

• Includes configurable gravity toward center

• Different cooling/speed mechanism

• Supports multiple gravity modes for different layout styles

Value

A matrix with x,y coordinates for each node.

cograph documentation built on April 1, 2026, 1:07 a.m.