ADE- Difference between Node Set and Initial Condition

Hello,

I have a very basic question: in ADE -> Simulation -> Convergence Aids, what is the difference between Node Set and Initial Condition? When should I use the formar and when the latter?

In Spectre Circuit Simulator Reference, it is stated: "The nodeset statement is used to provide an initial guess for nodes in any DC analysis or the initial condition calculation for the transient analysis."

This confuses me, because I don't see the difference with Initial condition, then..

Thanks!