verry.integrate.variationaleq

verry.integrate.variationaleq(fun, sol)

Return the right-hand side of variational equations.

Parameters:

• fun (Callable) – Right-hand side of the system.

• sol (Callable) – Solution of ODEs.

Return type:

Callable

Warning

fun must neither be a constant nor contain conditional branches (cf. Common pitfalls).

Notes

Variational equations of ODEs \(\mathrm{d}y/\mathrm{d}t=f(t,y)\) are defined as

\[\frac{\mathrm{d}v}{\mathrm{d}t} = (v\cdot\nabla)f(t,y),\]

where \(y=\phi(t)\) is a solution of ODEs.