API Reference: Classical Mechanics

The Python surface exposes classical-mechanics routines at top level (from pysicrs import euler_equations). See also Algorithms: Classical Mechanics.

import pysicrs

Rigid body

euler_equations

euler_equations(omega: list[float], moments: list[float], torque: list[float])
    -> list[float]

Rates \(\dot{\boldsymbol\omega}\) from Euler’s equations \(I_i\dot\omega_i = (I_j - I_k)\omega_j\omega_k + N_i\).

d = euler_equations([1.0, 0.0, 2.0], [2.0, 2.0, 1.0], [0.0, 0.0, 0.0])
print(d)   # torque-free rates

inertia_tensor

inertia_tensor(masses: list[float], positions: list[list[float]]) -> list[list[float]]

\(I_{ij}=\sum_a m_a(\|r_a\|^2\delta_{ij}-r_{a,i}r_{a,j})\).

euler_to_rotation

euler_to_rotation(phi: float, theta: float, psi: float) -> list[list[float]]

3D rotation matrix from ZXZ Euler angles \((\phi,\theta,\psi)\).

Rust-only (not yet bound)

function	purpose
hamiltonian_h, canonical_equations, poisson_bracket, canonical_transform	Hamiltonian picture
lagrangian_l, euler_lagrange, kinetic_energy, potential_energy	Lagrangian picture
torque_free	time-integrated free top
angular_momentum	\(\mathbf L = I\boldsymbol\omega\)
quaternion_to_rotation	quaternion parameterization