ValueFunction¶

class ValueFunction(*args)¶

Function mapping a field to a field.

Available constructors:

ValueFunction(spatialDim=1)

ValueFunction(g, spatialDim=1)

Parameters:	g : `Function` Function $g: \Rset^d \rightarrow \Rset^{d'}$ . spatialDim : int, $\geq 1$ Dimension $n$ of the domain $\cD$ .

Notes

Value functions act on fields to produce fields such that:

$f: \left| \begin{array}{rcl} \cM_N \times (\Rset^d)^N & \rightarrow & \cM_N \times (\Rset^{d'})^{N} \\ F & \mapsto & F' \end{array} \right.$

with $F = (\vect{t}_i, \vect{v}_i)_{1 \leq i \leq N}$ , $F' = (\vect{t}_i, \vect{v}'_i)_{1 \leq i \leq N}$ and $\cM_{N}$ a mesh of $\cD \subset \Rset^{n}$ .

A value function keeps the mesh unchanged: the input mesh is equal to the output mesh.

The field $F'$ is defined by the function $g: \Rset^d \rightarrow \Rset^{d'}$ :

$\forall \vect{t}_i \in \cM_N, \quad \vect{v}'_i = g(\vect{v}_i)$

The first constructor builds an object which evaluation operator is not defined (it throws a NotYetImplementedException). The instanciation of such an object is used to extract an actual ValueFunction from a Study.

Examples

>>> import openturns as ot

Create the function $g : \Rset \rightarrow \Rset$ defined by:

$g: \left|\begin{array}{rcl} \Rset & \rightarrow & \Rset \\ x & \mapsto & x^2 \end{array}\right.$

>>> g = ot.SymbolicFunction('x', 'x^2')

Convert $g$ into a value function with $n=1$ the dimension of the mesh of the field on which $g$ will be applied:

>>> n = 1
>>> tg = ot.RegularGrid(0.0, 0.2, 6)
>>> myValueFunction = ot.ValueFunction(g, tg)
>>> # Create a TimeSeries
>>> data = ot.Sample(tg.getN(), g.getInputDimension())
>>> for i in range(data.getSize()):
...     for j in range(data.getDimension()):
...         data[i, j] = i * data.getDimension() + j
>>> ts = ot.TimeSeries(tg, data)
>>> print(ts)
    [ t   v0  ]
0 : [ 0   0   ]
1 : [ 0.2 1   ]
2 : [ 0.4 2   ]
3 : [ 0.6 3   ]
4 : [ 0.8 4   ]
5 : [ 1   5   ]
>>> print(myValueFunction(ts))
    [ y0 ]
0 : [  0 ]
1 : [  1 ]
2 : [  4 ]
3 : [  9 ]
4 : [ 16 ]
5 : [ 25 ]

Methods

`getCallsNumber`()	Get the number of calls of the function.
`getClassName`()	Accessor to the object’s name.
`getFunction`()	Get the function $g$ .
`getId`()	Accessor to the object’s id.
`getInputDescription`()	Get the description of the input field values.
`getInputDimension`()	Get the dimension of the input field values.
`getInputMesh`()	Get the mesh associated to the input domain.
`getMarginal`(*args)	Get the marginal(s) at given indice(s).
`getName`()	Accessor to the object’s name.
`getOutputDescription`()	Get the description of the output field values.
`getOutputDimension`()	Get the dimension of the output field values.
`getOutputMesh`()	Get the mesh associated to the output domain.
`getShadowedId`()	Accessor to the object’s shadowed id.
`getVisibility`()	Accessor to the object’s visibility state.
`hasName`()	Test if the object is named.
`hasVisibleName`()	Test if the object has a distinguishable name.
`isActingPointwise`()	Whether the function acts point-wise.
`setInputDescription`(inputDescription)	Set the description of the input field values.
`setInputMesh`(inputMesh)	Set the mesh associated to the input domain.
`setName`(name)	Accessor to the object’s name.
`setOutputDescription`(outputDescription)	Set the description of the output field values.
`setOutputMesh`(outputMesh)	Set the mesh associated to the output domain.
`setShadowedId`(id)	Accessor to the object’s shadowed id.
`setVisibility`(visible)	Accessor to the object’s visibility state.

__call__
getSpatialDimension

__init__(*args)¶: Initialize self. See help(type(self)) for accurate signature.

getCallsNumber()¶

Get the number of calls of the function.

Returns:	callsNumber : int Counts the number of times the function has been called since its creation.

getClassName()¶

Accessor to the object’s name.

Returns:	class_name : str The object class name (object.__class__.__name__).

getFunction()¶

Get the function $g$ .

Returns:	g : `Function` Function $g: \Rset^d \rightarrow \Rset^{d'}$ .

Examples

>>> import openturns as ot
>>> g = ot.SymbolicFunction('x', 'x^2')
>>> n = 1
>>> mesh = ot.Mesh(n)
>>> myValueFunction = ot.ValueFunction(g, mesh)
>>> print(myValueFunction.getFunction())
[x]->[x^2]

getId()¶

Accessor to the object’s id.

Returns:	id : int Internal unique identifier.

getInputDescription()¶

Get the description of the input field values.

Returns:	inputDescription : `Description` Description of the input field values.

getInputDimension()¶

Get the dimension of the input field values.

Returns:	d : int Dimension $d$ of the input field values.

getInputMesh()¶

Get the mesh associated to the input domain.

Returns:	inputMesh : `Mesh` The input mesh $\cM_{N'}$ .

getMarginal(*args)¶

Get the marginal(s) at given indice(s).

Parameters:	i : int or list of ints, $0 \leq i < d'$ Indice(s) of the marginal(s) to be extracted.
Returns:	function : `ValueFunction` The initial function restricted to the concerned marginal(s) at the indice(s) $i$ .

getName()¶

Accessor to the object’s name.

Returns:	name : str The name of the object.

getOutputDescription()¶

Get the description of the output field values.

Returns:	outputDescription : `Description` Description of the output field values.

getOutputDimension()¶

Get the dimension of the output field values.

Returns:	d’ : int Dimension $d'$ of the output field values.

getOutputMesh()¶

Get the mesh associated to the output domain.

Returns:	outputMesh : `Mesh` The output mesh $\cM_{N'}$ .

getShadowedId()¶

Accessor to the object’s shadowed id.

Returns:	id : int Internal unique identifier.

getVisibility()¶

Accessor to the object’s visibility state.

Returns:	visible : bool Visibility flag.

hasName()¶

Test if the object is named.

Returns:	hasName : bool True if the name is not empty.

hasVisibleName()¶

Test if the object has a distinguishable name.

Returns:	hasVisibleName : bool True if the name is not empty and not the default one.

isActingPointwise()¶

Whether the function acts point-wise.

Returns:	pointWise : bool Returns true if the function evaluation at each vertex depends only on the vertex or the value at the vertex.

setInputDescription(inputDescription)¶

Set the description of the input field values.

Parameters:	inputDescription : sequence of str Description of the input field values.

setInputMesh(inputMesh)¶

Set the mesh associated to the input domain.

Parameters:	inputMesh : `Mesh` The input mesh $\cM_{N'}$ .

setName(name)¶

Accessor to the object’s name.

Parameters:	name : str The name of the object.

setOutputDescription(outputDescription)¶

Set the description of the output field values.

Parameters:	outputDescription : sequence of str Describes the outputs of the output field values.

setOutputMesh(outputMesh)¶

Set the mesh associated to the output domain.

Parameters:	outputMesh : `Mesh` The output mesh $\cM_{N'}$ .

setShadowedId(id)¶

Accessor to the object’s shadowed id.

Parameters:	id : int Internal unique identifier.

setVisibility(visible)¶

Accessor to the object’s visibility state.

Parameters:	visible : bool Visibility flag.

OpenTURNS

An Open source initiative for the Treatment of Uncertainties, Risks'N Statistics

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