layout_physics

defaults to force-directed layout ( fcose ) with animation on, but callers can select other options offered by cytoscape. js.
a toggle leaves layout animation and live physics on for force-directed layouts instead of settling immediately.
live physics is the custom obsidian-style simulation in graph-physics.ts ( force core: physics-core.js ), regardless of which force-directed batch layout produced the initial settle.
forces are central gravity toward the centroid, linear edge springs, and inverse-square node repulsion; every childless node participates, including disconnected orphans.
group container constraints live in graph-groups.ts: each leaf carries data ( ' groupIds' ); disjoint groups are pushed apart after batch cola / fcose and during Animate; groups that share a member ( multi-membership, e. g. tags ) may overlap around the shared node.
the simulation is deterministic ( no randomness ) and converges slowly over tens of seconds, then sleeps; interactions wake it instead of restarting it.
dragging pins the held node while the sim keeps running around it; release rejoins the node at rest with no snap; clicks never disturb the sim.
cycling the Animate toggle pauses and resumes the same simulation state, so it converges to the same attractor as leaving it on.

Interactive page: layout_physics