lyapunov_max¶
-
gala.dynamics.
lyapunov_max
(w0, integrator, dt, n_steps, d0=1e-05, n_steps_per_pullback=10, noffset_orbits=8, t1=0.0, units=None)[source]¶ Compute the maximum Lyapunov exponent of an orbit by integrating many nearby orbits (
noffset
) separated with isotropically distributed directions but the same initial deviation length,d0
. This algorithm re-normalizes the offset orbits everyn_steps_per_pullback
steps.Parameters: w0 :
PhaseSpacePosition
, array_likeInitial conditions.
integrator :
Integrator
An instantiated
Integrator
object. Must have a run() method.dt : numeric
Timestep.
n_steps : int
Number of steps to run for.
d0 : numeric (optional)
The initial separation.
n_steps_per_pullback : int (optional)
Number of steps to run before re-normalizing the offset vectors.
noffset_orbits : int (optional)
Number of offset orbits to run.
t1 : numeric (optional)
Time of initial conditions. Assumed to be t=0.
units :
UnitSystem
(optional)If passing in an array (not a
PhaseSpacePosition
), you must specify a unit system.Returns: LEs :
Quantity
Lyapunov exponents calculated from each offset / deviation orbit.
orbit :
CartesianOrbit