Fast Multipole Gravity Lab

Adaptive-quadtree FMM with order 1–5 Cartesian multipole / local expansions and a dual-tree far/near decomposition.

M2M → M2L → L2L → P2P

Settings

Scene

Preset Spiral galaxy Binary galaxies Orbital ring Cold collapse Three-body tracers

Particles 1024

↺ Reset ❚❚ Pause ▶ Step

FMM solver

Expansion order 3

Separation ratio 1.60

Leaf capacity 32

Physics

Gravity 0.65

Softening 0.018

Timestep 0.003

View

Trails Quadtree Accel vectors Sampled error

Click to inject a particle cloud · Shift-click to add a massive body · Space pauses