Hierarchical N-body solver

Fast Multipole Gravity Lab

Interactive 2D N-body with a Barnes-Hut/FMM-like multipole hierarchy. Click to inject, Shift-click for a massive body. Space pauses.

M2M → M2L → L2L → P2P

Particles0

FPS0

Solve ms0

Nodes0

M2L0

Sample error0

Preset

Particle count 1024

Expansion order 3 Separation ratio 1.60 Leaf capacity 32

Gravity 0.65 Softening 0.018 Timestep 0.003

Particle trails

Quadtree overlay

Acceleration vectors

Sample error

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