ostk.astrodynamics.trajectory.state.NumericalSolver¶

class NumericalSolver( self: ostk.astrodynamics.trajectory.state.NumericalSolver, log_type: ostk.mathematics.solver.NumericalSolver.LogType, stepper_type: ostk.mathematics.solver.NumericalSolver.StepperType, time_step: ostk.core.type.Real, relative_tolerance: ostk.core.type.Real, absolute_tolerance: ostk.core.type.Real, root_solver: ostk.astrodynamics.RootSolver = RootSolver.default(), )¶

Bases: NumericalSolver

A numerical solver is used to integrate the trajectory of a dynamical system.

The numerical solver can be used to integrate the trajectory of a dynamical system to a given instant, or to a set of instants, or until an Event Condition is met.

Constructor.

Parameters:

log_type (NumericalSolver.LogType) -- The type of logging.
stepper_type (NumericalSolver.StepperType) -- The type of stepper.
time_step (float) -- The time step.
relative_tolerance (float) -- The relative tolerance.
absolute_tolerance (float) -- The absolute tolerance.
root_solver (RootSolver, optional) -- The root solver. Defaults to RootSolver.Default().

Methods

`conditional`	Return a conditional numerical solver.
`default`	Return the default numerical solver.
`default_conditional`	Return the default conditional numerical solver.
`fixed_step_size`	Return a Numerical Solver using a fixed stepper.
`get_absolute_tolerance`	Get the absolute tolerance of the solver.
`get_log_type`	Get the log type of the solver.
`get_observed_state_vectors`	Get the observed state vectors from the last integration.
`get_observed_states`	Get the observed states.
`get_relative_tolerance`	Get the relative tolerance of the solver.
`get_root_solver`	Get the root solver.
`get_stepper_type`	Get the stepper type of the solver.
`get_time_step`	Get the time step of the solver.
`integrate_duration`	Overloaded function.
`integrate_time`	Overloaded function.
`is_defined`	Check if the numerical solver is defined.
`string_from_log_type`	Get string representation of a log type.
`string_from_stepper_type`	Get string representation of a stepper type.
`undefined`	Return an undefined numerical solver.

class ConditionSolution¶

Bases: pybind11_object

The solution to an event condition.

property condition_is_satisfied¶

Whether the event condition is satisfied.

Type:: bool

property iteration_count¶

The number of iterations required to find the solution.

Type:: int

property root_solver_has_converged¶

Whether the root solver has converged.

Type:: bool

property state¶

The state of the trajectory.

Type:: State

class LogType( self: ostk.mathematics.solver.NumericalSolver.LogType, value: int, )¶

Bases: pybind11_object

Members:

NoLog

LogConstant

LogAdaptive

property name¶

class StepperType( self: ostk.mathematics.solver.NumericalSolver.StepperType, value: int, )¶

Bases: pybind11_object

Members:

RungeKutta4

RungeKuttaCashKarp54

RungeKuttaFehlberg78

RungeKuttaDopri5

property name¶

static conditional( arg0: ostk.core.type.Real, arg1: ostk.core.type.Real, arg2: ostk.core.type.Real, arg3: Callable[[ostk.astrodynamics.trajectory.State], None], ) → ostk.astrodynamics.trajectory.state.NumericalSolver¶

Return a conditional numerical solver.

Returns:: The conditional numerical solver.
Return type:: NumericalSolver

static default() → ostk.astrodynamics.trajectory.state.NumericalSolver¶

Return the default numerical solver.

Returns:: The default numerical solver.
Return type:: NumericalSolver

static default_conditional( state_logger: Callable[[ostk.astrodynamics.trajectory.State], None] = None, ) → ostk.astrodynamics.trajectory.state.NumericalSolver¶

Return the default conditional numerical solver.

Parameters:: state_logger (StateLogger, optional) -- The state logger. Defaults to None.
Returns:: The default conditional numerical solver.
Return type:: NumericalSolver

static fixed_step_size( stepper_type: ostk.mathematics.solver.NumericalSolver.StepperType, time_step: ostk.core.type.Real, ) → ostk.astrodynamics.trajectory.state.NumericalSolver¶

Return a Numerical Solver using a fixed stepper.

Returns:: The numerical solver.
Return type:: NumericalSolver

get_absolute_tolerance( self: ostk.mathematics.solver.NumericalSolver, ) → ostk.core.type.Real¶

Get the absolute tolerance of the solver.

Returns:: The absolute tolerance value.
Return type:: float

Example

>>> solver = NumericalSolver.default()
>>> abs_tol = solver.get_absolute_tolerance()

get_log_type( self: ostk.mathematics.solver.NumericalSolver, ) → ostk::mathematics::solver::NumericalSolver::LogType¶

Get the log type of the solver.

Returns:: The log type.
Return type:: NumericalSolver.LogType

Example

>>> solver = NumericalSolver.default()
>>> log_type = solver.get_log_type()

get_observed_state_vectors( self: ostk.mathematics.solver.NumericalSolver, ) → list[tuple[numpy.ndarray[numpy.float64[m, 1]], float]]¶

Get the observed state vectors from the last integration.

Returns:: List of observed state vectors during integration.
Return type:: list

Example

>>> solver = NumericalSolver.default()
>>> # After performing integration...
>>> states = solver.get_observed_state_vectors()

get_observed_states( self: ostk.astrodynamics.trajectory.state.NumericalSolver, ) → list[ostk.astrodynamics.trajectory.State]¶

Get the observed states.

Returns:: The observed states.
Return type:: list[State]

get_relative_tolerance( self: ostk.mathematics.solver.NumericalSolver, ) → ostk.core.type.Real¶

Get the relative tolerance of the solver.

Returns:: The relative tolerance value.
Return type:: float

Example

>>> solver = NumericalSolver.default()
>>> rel_tol = solver.get_relative_tolerance()

get_root_solver( self: ostk.astrodynamics.trajectory.state.NumericalSolver, ) → ostk.astrodynamics.RootSolver¶

Get the root solver.

Returns:: The root solver.
Return type:: RootSolver

get_stepper_type( self: ostk.mathematics.solver.NumericalSolver, ) → ostk::mathematics::solver::NumericalSolver::StepperType¶

Get the stepper type of the solver.

Returns:: The stepper type.
Return type:: NumericalSolver.StepperType

Example

>>> solver = NumericalSolver.default()
>>> stepper_type = solver.get_stepper_type()

get_time_step( self: ostk.mathematics.solver.NumericalSolver, ) → ostk.core.type.Real¶

Get the time step of the solver.

Returns:: The time step value.
Return type:: float

Example

>>> solver = NumericalSolver.default()
>>> time_step = solver.get_time_step()

integrate_duration(*args, **kwargs)¶

Overloaded function.

integrate_duration(self: ostk.mathematics.solver.NumericalSolver, arg0: numpy.ndarray[numpy.float64[m, 1]], arg1: ostk.core.type.Real, arg2: object) -> tuple[numpy.ndarray[numpy.float64[m, 1]], float]
Integrate a system of differential equations for a specified duration.
Args:
state_vector (StateVector): Initial state vector. duration_in_seconds (float): Integration duration in seconds. system_of_equations (callable): Function defining the system of ODEs.

Signature: f(x, dxdt, t) -> StateVector

Returns:
StateVector: Final state vector after integration.

Example:
>>> def equations(x, dxdt, t): ... dxdt[0] = x[1] # dx/dt = v ... dxdt[1] = -x[0] # dv/dt = -x (harmonic oscillator) ... return dxdt >>> solver = NumericalSolver.default() >>> initial_state = [1.0, 0.0] # x=1, v=0 >>> final_state = solver.integrate_duration(initial_state, 1.0, equations)
integrate_duration(self: ostk.mathematics.solver.NumericalSolver, arg0: numpy.ndarray[numpy.float64[m, 1]], arg1: list[ostk.core.type.Real], arg2: object) -> list[tuple[numpy.ndarray[numpy.float64[m, 1]], float]]
Integrate a system of differential equations at multiple duration points.
Args:
state_vector (StateVector): Initial state vector. duration_array (list): Array of duration values in seconds. system_of_equations (callable): Function defining the system of ODEs.

Signature: f(x, dxdt, t) -> StateVector

Returns:
list: State vectors at each duration point.

Example:
>>> def equations(x, dxdt, t): ... dxdt[0] = x[1] # dx/dt = v ... dxdt[1] = -x[0] # dv/dt = -x (harmonic oscillator) ... return dxdt >>> solver = NumericalSolver.default() >>> initial_state = [1.0, 0.0] >>> durations = [0.5, 1.0, 1.5] >>> states = solver.integrate_duration(initial_state, durations, equations)

integrate_time(*args, **kwargs)¶

Overloaded function.

integrate_time(self: ostk.astrodynamics.trajectory.state.NumericalSolver, state: ostk.astrodynamics.trajectory.State, instant: ostk.physics.time.Instant, system_of_equations: object) -> ostk.astrodynamics.trajectory.State

Integrate the trajectory to a given instant.

Args:
state (State): The initial state of the trajectory. instant (Instant): The instant to integrate to. system_of_equations (callable): The system of equations.

Returns:
State: The state at the requested time.
integrate_time(self: ostk.astrodynamics.trajectory.state.NumericalSolver, state: ostk.astrodynamics.trajectory.State, instants: list[ostk.physics.time.Instant], system_of_equations: object) -> list[ostk.astrodynamics.trajectory.State]

Integrate the trajectory to a set of instants.

Args:
state (State): The initial state of the trajectory. instants (list[Instant]): The instants to integrate to. system_of_equations (callable): The system of equations.

Returns:
list[State]: The states at the requested times.
integrate_time(self: ostk.astrodynamics.trajectory.state.NumericalSolver, state: ostk.astrodynamics.trajectory.State, instant: ostk.physics.time.Instant, system_of_equations: object, event_condition: ostk::astrodynamics::EventCondition) -> ostk.astrodynamics.trajectory.state.NumericalSolver.ConditionSolution

Integrate the trajectory to a given instant, with an event condition.

Args:
state (State): The initial state of the trajectory. instant (Instant): The instant to integrate to. system_of_equations (callable): The system of equations. event_condition (EventCondition): The event condition.

Returns:
ConditionSolution: The solution to the event condition.

is_defined( self: ostk.astrodynamics.trajectory.state.NumericalSolver, ) → bool¶

Check if the numerical solver is defined.

Returns:: True if the numerical solver is defined, False otherwise.
Return type:: bool

static string_from_log_type( log_type: ostk::mathematics::solver::NumericalSolver::LogType, ) → ostk.core.type.String¶

Get string representation of a log type.

Parameters:: log_type (NumericalSolver.LogType) -- The log type.
Returns:: String representation of the log type.
Return type:: str

Example

>>> NumericalSolver.string_from_log_type(NumericalSolver.LogType.NoLog)

static string_from_stepper_type( stepper_type: ostk::mathematics::solver::NumericalSolver::StepperType, ) → ostk.core.type.String¶

Get string representation of a stepper type.

Parameters:: stepper_type (NumericalSolver.StepperType) -- The stepper type.
Returns:: String representation of the stepper type.
Return type:: str

Example

>>> NumericalSolver.string_from_stepper_type(NumericalSolver.StepperType.RungeKutta4)

static undefined() → ostk.astrodynamics.trajectory.state.NumericalSolver¶

Return an undefined numerical solver.

Returns:: The undefined numerical solver.
Return type:: NumericalSolver