← moiseevigor/elliptic

Celestial mechanics & orbital dynamics

Elliptic integrals · 3D visualisation

Arc Length & Celestial Mechanics

Derive the arc length of an ellipse via $E(\varphi|m)$, trace Keplerian orbits in 3D, solve Kepler's equation numerically, and watch the Carlson duplication algorithm converge. Includes a live Mercury perihelion precession demo.

elliptic12 ellipticBDJ carlsonRF arclength_ellipse

Jacobi elliptic functions

Nonlinear dynamics · Jacobi sn/cn/dn

Physical Pendulum & Exact Trajectories

Exact period for large-amplitude oscillations via $K(k^2)$, live pendulum animation using $\mathrm{sn}(t|m)$, phase-portrait with separatrix, and period divergence as $\theta_0 \to \pi$. Extends to compound pendula.

ellipj elliptic12 carlsonRF cel1

Rigid body rotation coming soon

Euler–Poinsot Motion

Torque-free rotation of an asymmetric top: $\omega_1 = \omega_0\,\mathrm{cn}(t|m)$, polhode animation, and Euler angle integration.

ellipj jacobiEDJ elliptic12

Nonlinear waves & signal processing

KdV equation coming soon

Cnoidal Waves

Exact KdV cnoidal wave solution $u(x,t) = A\,\mathrm{cn}^2(\kappa(x-vt)|m)$ animated across the soliton limit $m \to 1$.

ellipj

Weierstrass & modular forms

Complex analysis coming soon

Weierstrass ℘ Function & Elliptic Curves

Domain-colouring of $\wp(z)$ over the complex plane, lattice geometry from invariants $g_2, g_3$, and the group law on $y^2 = 4x^3 - g_2 x - g_3$.

weierstrassP weierstrassZeta weierstrassInvariants