collide.radius()

collide.radius([radius])

If radius is specified, sets the radius accessor to the specified number or function, re-evaluates the radius accessor for each node, and returns this force. If radius is not specified, returns the current radius accessor, which defaults to:

function radius() {
  return 1;
}

The radius accessor is invoked for each node in the simulation, being passed the node and its zero-based index. The resulting number is then stored internally, such that the radius of each node is only recomputed when the force is initialized or when this method is called with a new radius, and not on every application of the force.