NumericalTools.Ivp Class Reference

Central class for the port of the SciPy Solve_Ivp method to perform numerical integration of a system of ordinary differential equations using the error minimizing approaches RK23, RK45 or DOP853. More...

Classes
struct	Event
	Structure to define an Event for the DE solver. More...
class	OdeResult
	This class is a strut-like wrapper for the information associated with a DE solution. More...

Public Types
enum	Method { RK23, RK45, DOP853 }

Public Member Functions
delegate double []	DiffEqFunction (double t, double[] y, params object[] args)
	Prototype for a function that defines the system of differential equations to be solved. More...
delegate double	EventFunction (double t, double[] y)
	Prototype for an EventFunction to be evaluated as the DE is being solved. More...
delegate void	RTEventCallback (double t, double[] y)
	A function to be called when IvpRealtime events are triggered. More...

Static Public Member Functions
static List< int >	FindActiveEvents (double[] g, double[] g_new, double[] direction)
	Not for external use. This method is public to allow access by IvpRealtime. More...
static OdeResult	SolveIvp (DiffEqFunction fun, double[] t_span, double[] y0, Method method=Method.RK45, double[] t_eval=null, bool dense_output=false, List< Event > events=null, bool vectorized=false, params object[] args)
	SolveIvp is the partial implementation of the SciPy solve_ivp function. More...

Static Public Attributes
static bool []	isTerminal
	Not for external use. This method is public to allow access by IvpRealtime. More...
static	List< int >
	Not for external use. This method is public to allow access by IvpRealtime. More...

Detailed Description

Central class for the port of the SciPy Solve_Ivp method to perform numerical integration of a system of ordinary differential equations using the error minimizing approaches RK23, RK45 or DOP853.

A summary of the features provided is at http://nbodyphysics.com/blog/numericaltools See the SciPy solve_ivp documentation for an in-depth reference.

Member Function Documentation

DiffEqFunction()

delegate double [] NumericalTools.Ivp.DiffEqFunction	(	double	t,
		double []	y,
		params object []	args
	)

Prototype for a function that defines the system of differential equations to be solved.

Parameters

t	time of the current state of the DE system
y	Current state of the DE systems
args	(optional) arguments as object[] that can be referenced by the DE system

Returns

EventFunction()

delegate double NumericalTools.Ivp.EventFunction	(	double	t,
		double []	y
	)

Prototype for an EventFunction to be evaluated as the DE is being solved.

If the event function returns zero, the event MAY be triggered, depending on whether the associated Event structure has indicated that the result of the function must be in positive or negative direction.

Parameters

t	time of the current state of the DE system
y	Current state of the DE systems

Returns

FindActiveEvents()

static List<int> NumericalTools.Ivp.FindActiveEvents ( double []  g, double []  g_new, double []  direction  )

inlinestatic

Not for external use. This method is public to allow access by IvpRealtime.

Parameters

g
g_new
direction

Returns

RTEventCallback()

delegate void NumericalTools.Ivp.RTEventCallback	(	double	t,
		double []	y
	)

A function to be called when IvpRealtime events are triggered.

Parameters

t	time of the current state of the DE system
y	Current state of the DE systems

SolveIvp()

static OdeResult NumericalTools.Ivp.SolveIvp ( DiffEqFunction  fun, double []  t_span, double []  y0, Method  method = Method.RK45, double []  t_eval = null, bool  dense_output = false, List< Event >  events = null, bool  vectorized = false, params object []  args  )

inlinestatic

SolveIvp is the partial implementation of the SciPy solve_ivp function.

The methods RK23, RK45 and DOP853 are implemented. Unit tests to compare the results of each method to the output from SciPy under python can be found in the QA directory of the asset.

Example code can be found in the NUnit tests as well as the directory: SciPyBased/Scenes/Solve_Ivp.

For a general overview see the Numerical Tools documentation at nbodyphysics.com

Parameters

fun	Function that provides the description of the system of DEs
t_span	(double[2]) Time range (from..to) to solve the DE system for
y0	(double[n]) Initial conditions for the DE system
method	The algorithm to use
t_eval	A list of specific times that the DE system should be recorded at
dense_output	(bool) Record intermediate values for later use with OdeResult.Call()
events	List of event structs
vectorized	Unsupported
args

Returns

Member Data Documentation

isTerminal

bool [] NumericalTools.Ivp.isTerminal

static

Not for external use. This method is public to allow access by IvpRealtime.

Parameters

events

Returns

List< int >

NumericalTools.Ivp.List< int >

static

Not for external use. This method is public to allow access by IvpRealtime.

Parameters

sol
events
active_events
is_terminal
t_old
t

Returns

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The documentation for this class was generated from the following file:

• DE Solver/Assets/NumericalTools/SciPyBased/Scripts/Solvers/Ivp/Ivp.cs