RK5Integrator¶

class
gala.integrate.
RK5Integrator
(func, func_args=(), func_units=None, progress=False)[source]¶ Bases:
gala.integrate.core.Integrator
Initialize a 5th order RungeKutta integrator given a function for computing derivatives with respect to the independent variables. The function should, at minimum, take the independent variable as the first argument, and the coordinates as a single vector as the second argument. For notation and variable names, we assume this independent variable is time, t, and the coordinate vector is named x, though it could contain a mixture of coordinates and momenta for solving Hamilton’s equations, for example.
 Parameters
 funcfunc
A callable object that computes the phasespace coordinate derivatives with respect to the independent variable at a point in phase space.
 func_argstuple (optional)
Any extra arguments for the function.
 func_units
UnitSystem
(optional) If using units, this is the unit system assumed by the integrand function.
Methods Summary
run
(w0[, mmap])Run the integrator starting from the specified phasespace position.
step
(t, w, dt)Step forward the vector w by the given timestep.
Methods Documentation

run
(w0, mmap=None, **time_spec)[source]¶ Run the integrator starting from the specified phasespace position. The initial conditions
w0
should be aPhaseSpacePosition
instance.There are a few combinations of keyword arguments accepted for specifying the timestepping. For example, you can specify a fixed timestep (
dt
) and a number of steps (n_steps
), or an array of times:dt, n_steps[, t1] : (numeric, int[, numeric]) A fixed timestep dt and a number of steps to run for. dt, t1, t2 : (numeric, numeric, numeric) A fixed timestep dt, an initial time, and a final time. t : array_like An array of times to solve on.
Warning
Right now, this always returns a
Orbit
instance. This is wrong and will change!Todo
Allow specifying the return orbit class.
 Parameters
 w0
PhaseSpacePosition
Initial conditions.
 **time_spec
Timestep information passed to
parse_time_specification
.
 w0
 Returns
 orbit
Orbit
 orbit