link.id([id]) If id is specified, sets the node id accessor to the specified function and returns this force

manyBody.theta([theta]) If theta is specified, sets the Barnes–Hut approximation criterion to the specified

manyBody.strength([strength]) If strength is specified, sets the strength accessor to the specified number

collide.iterations([iterations]) If iterations is specified, sets the number of iterations per application

simulation.find(x, y[, radius]) Returns the node closest to the position ⟨x,y⟩ with

simulation.velocityDecay([decay]) If decay is specified, sets the velocity decay factor to the specified number

simulation.alphaDecay([decay]) If decay is specified, sets the

x.x([x]) If x is specified, sets the x-coordinate accessor to the specified number or function, re-evaluates

d3.forceCenter([x, y]) Creates a new centering force with the specified

force.initialize(nodes) Assigns the array of nodes to this force. This method is called when a force is bound