javascript - d3 clustered force layout, distance between cluster center -

(i'm d3js newbie)

i'm using d3.layout.force visualize graph of nodes divided clusters, (even if in version every cluster's node keep gravity focus set cluster's center):

http://bl.ocks.org/mbostock/1747543

what i'd accomplish keep each cluster separated other min distance.

i set random points each cluster center @ initial stage:

for(var = 0; < clusterlength; i++) {     var basex = 3     var basey = 7      var x = halton(i + 1, basex) * width + (math.random() * 50)     var y = halton(i + 1, basey) * height + (math.random() * 50)           clustercoords.push({        x: x,       y: y     })      j += 1   } 

then i'd able reposition each cluster keeping distance between others.

hope it's clear.

this padding variable used in mbostock example.

see example padding set 30: http://bl.ocks.org/mccannf/5548435