CODEWITHSUNDEEP
python-3.xigraphnetworkx
DanielTheRocketMan
DanielTheRocketMan

Reputation: 3249

i-graph-python argument equivalent to pos in networkx

In networkx I am able to input the positions of node to be drawn using the second argument of

nx.draw(G, pos)

For instance I can do something like this:

    pos[sourceNode]=(x1,y1)
    pos[targetNode]=(x2,y2)

I know that i-graph has an argument layout, but I was not able to discover how to use it!

Can you help me?

Upvotes: 1

Views: 114

Answers (1)

G5W
G5W

Reputation: 37661

You are right; in order to position the nodes yourself, you need to use the layout argument to plot. Here are some basic examples showing how to use the automatic layout functions and how to make your own.

First, let's make a simple graph as an example. I am setting the random seed so that my results will be reproducible.

from igraph import * 
import random

random.seed(123)
g = Graph.Erdos_Renyi(5, 0.5)
plot(g)

First plot - no layout

When you just plot like this, you have no control of the layout.

There are a number of built-in functions to use specific algorithms for generating layouts. 

LO = g.layout_kamada_kawai()
plot(g, layout=LO)

Kamada-Kawai Layout

But if you want to take complete control, you need to build your own layout. A layout is just a sequence of [x,y] pairs that say where to place the nodes. While x works the expected way, the low y coordinates are at the top and the high y-values are at the bottom, so you need to do a little transposition to set up your layout. 

LO = [[0.0,1.0], [1.0,0.0], [1.0,1.0], [0.0,0.0], [0.5,-0.5]]
plot(g, layout=LO)

Hand-crafted layout

Upvotes: 1

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