Chaos Lab

Discrete map · 2D · dim 2

Arnold cat map

Toral automorphism with eigenvalues (3 ± √5)/2. Exponential stretching along the unstable eigendirection, then folding by mod 1. Mixes phase space exponentially; popular in image scrambling.

Three iterations of the Arnold cat map on a 32×32 quadrant pattern: mixing in action.

Equations

(x, y) ↦ ((2x + y) mod 1, (x + y) mod 1)

At a glance

Parameters(no free parameter)
Chaotic foralways
Lyapunov exponentλ = ln((3 + √5)/2) ≈ 0.962
HistoryVladimir Arnold's 1960s illustration of hyperbolic mixing.

Try it

Open the interactive playground at /tools/arnold-cat.

See also

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8-question flashcard quiz on arnold cat map

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