# FilonQuadrature¶

class FilonQuadrature(*args)

Tensorized integration algorithm of Gauss-Legendre.

Parameters: n : int, The discretization used by the algorithm. The integration algorithm will be regularly discretized by points. omega : float The default pulsation in the oscillating kernel. Default value is 1.0. kind : int, The type of oscillating kernel defining the integral, see notes. Default value is 0.

Notes

The Filon algorithm enables to approximate the definite integral:

with , , and:

This algorithm is based on a regular partition of the interval , the function being approximated by a quadratic function on three consecutive points. This algorithm provides an approximation of order when . When , the result is returned as a Point of dimension 2, the first component being the real part of the result and the second component the imaginary part.

Examples

Create a Filon algorithm:

>>> import openturns as ot
>>> algo = ot.FilonQuadrature(100)
>>> algo = ot.FilonQuadrature(100, 10.0)


Methods

 getClassName() Accessor to the object’s name. getId() Accessor to the object’s id. getKind() Accessor to the kind of oscillating weight defining the integral. getN() Accessor to the discretization of the algorithm. getName() Accessor to the object’s name. getOmega() Accessor to the default pulsation. 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. integrate(*args) Evaluation of the integral of on an interval. setKind(kind) Accessor to the kind of oscillating weight defining the integral. setN(n) Accessor to the discretization of the algorithm. setName(name) Accessor to the object’s name. setOmega(omega) Accessor to the default pulsation. setShadowedId(id) Accessor to the object’s shadowed id. setVisibility(visible) Accessor to the object’s visibility state.
__init__(*args)

Initialize self. See help(type(self)) for accurate signature.

getClassName()

Accessor to the object’s name.

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

Accessor to the object’s id.

Returns: id : int Internal unique identifier.
getKind()

Accessor to the kind of oscillating weight defining the integral.

Returns: kind : int The oscillating weight function defining the integral, see the notes.
getN()

Accessor to the discretization of the algorithm.

Returns: n : integer The discretization used by the algorithm.
getName()

Accessor to the object’s name.

Returns: name : str The name of the object.
getOmega()

Accessor to the default pulsation.

Returns: omega : float The pulsation used in the integrate method if not explicitely given.
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.
integrate(*args)

Evaluation of the integral of on an interval.

Available usages:

integrate(f, interval)

integrate(f, interval, omega)

Parameters: f : The integrand function. omega : float The pulsation in the weight function. This value superseeds the value given in the constructor. interval : The integration domain. value : Point Approximation of the integral. Its dimension is if , otherwise it is with the first components corresponding to the real part of the integral and the remaining ones to the imaginary part.

Examples

>>> import openturns as ot
>>> import math
>>> f = ot.SymbolicFunction(['t'], ['log(1+t)'])
>>> a = 0.5
>>> b = a + 8.0 * math.pi
>>> n = 100
>>> omega = 1000.0
>>> kind = 0
>>> algoF = ot.FilonQuadrature(n, omega, kind)
>>> value = algoF.integrate(f, ot.Interval(a, b))
>>> print(value[0])
-0.00134...
>>> kind = 1
>>> algoF = ot.FilonQuadrature(n, omega, kind)
>>> value = algoF.integrate(f, ot.Interval(a, b))
>>> print(value[0])
0.00254...
>>> kind = 2
>>> algoF = ot.FilonQuadrature(n, omega, kind)
>>> value = algoF.integrate(f, ot.Interval(a, b))
>>> print(value[0])
-0.00134...
>>> print(value[1])
0.00254...

setKind(kind)

Accessor to the kind of oscillating weight defining the integral.

Parameters: kind : int The oscillating weight function defining the integral, see the notes.
setN(n)

Accessor to the discretization of the algorithm.

Parameters: n : integer, The discretization used by the algorithm.
setName(name)

Accessor to the object’s name.

Parameters: name : str The name of the object.
setOmega(omega)

Accessor to the default pulsation.

Parameters: omega : float The pulsation used in the integrate method if not explicitely given.
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.