RungeKutta

(Source code, png)

class RungeKutta(*args)

Runge-Kutta fourth-order method.

Parameters:

transitionFunctionFunction

The function defining the flow of the ordinary differential equation. Must have one parameter.

See also

ODESolver

Examples

>>> import openturns as ot
>>> f = ot.SymbolicFunction(['t', 'y0', 'y1'], ['t - y0', 'y1 + t^2'])
>>> phi = ot.ParametricFunction(f, [0], [0.0])
>>> solver = ot.RungeKutta(phi)
>>> Y0 = [1.0, -1.0]
>>> nt = 100
>>> timeGrid = [(i**2.0) / (nt - 1.0)**2.0 for i in range(nt)]
>>> result = solver.solve(Y0, timeGrid)

Methods

getClassName()	Accessor to the object's name.
getId()	Accessor to the object's id.
getName()	Accessor to the object's name.
getShadowedId()	Accessor to the object's shadowed id.
getTransitionFunction()	Transition function accessor.
getVisibility()	Accessor to the object's visibility state.
hasName()	Test if the object is named.
hasVisibleName()	Test if the object has a distinguishable name.
setName(name)	Accessor to the object's name.
setShadowedId(id)	Accessor to the object's shadowed id.
setTransitionFunction(transitionFunction)	Transition function accessor.
setVisibility(visible)	Accessor to the object's visibility state.
solve(*args)	Solve ODE.

__init__(*args)

getClassName()

Accessor to the object’s name.

Returns:

class_namestr

The object class name (object.__class__.__name__).

getId()

Accessor to the object’s id.

Returns:

idint

Internal unique identifier.

getName()

Accessor to the object’s name.

Returns:

namestr

The name of the object.

getShadowedId()

Accessor to the object’s shadowed id.

Returns:

idint

Internal unique identifier.

getTransitionFunction()

Transition function accessor.

Returns:

transitionFunctionFieldFunction

Transition function.

getVisibility()

Accessor to the object’s visibility state.

Returns:

visiblebool

Visibility flag.

hasName()

Test if the object is named.

Returns:

hasNamebool

True if the name is not empty.

hasVisibleName()

Test if the object has a distinguishable name.

Returns:

hasVisibleNamebool

True if the name is not empty and not the default one.

setName(name)

Accessor to the object’s name.

Parameters:

namestr

The name of the object.

setShadowedId(id)

Accessor to the object’s shadowed id.

Parameters:

idint

Internal unique identifier.

setTransitionFunction(transitionFunction)

Transition function accessor.

Parameters:

transitionFunctionFieldFunction

Transition function.

setVisibility(visible)

Accessor to the object’s visibility state.

Parameters:

visiblebool

Visibility flag.

solve(*args)

Solve ODE.

Parameters:

initialStatesequence of float

Initial value of the equation

timeGridsequence of float or Mesh of dimension 1

Time stamps, ie values of at which the solution is computed.

Returns:

valuesSample

The solution of the equation at grid points.

Examples using the class

Logistic growth model

Logistic growth model