chebyshev#

Implementations of the transformation classes from ChebyshevPolynomial (polynomials in the Chebyshev basis of the first kind) to:

LagrangePolynomial (polynomials in the Lagrange basis)
NewtonPolynomial (polynomials in the Newton basis)
CanonicalPolynomial (polynomials in the canonical basis)

class minterpy.transformations.chebyshev.ChebyshevToLagrange(origin_poly)[source]#

Bases: TransformationABC

Transformation from the Chebyshev basis to the Lagrange basis.

Properties

`grid`	The grid of the origin polynomial.
`multi_index`	The multi index set of the origin polynomial (and also the target polynomial).
`transformation_operator`	The polynomial basis transformation operator.

Parameters:: origin_poly (MultivariatePolynomialSingleABC)

origin_type#: alias of ChebyshevPolynomial

target_type#: alias of LagrangePolynomial

_get_transformation_operator()#

Construct the Chebyshev to Lagrange transformation operator.

Parameters:: transformation (TransformationABC) – The transformer instance with information about the origin polynomial (an instance of ChebyshevPolynomial) and the target type (LagrangePolynomial).
Returns:: The Chebyshev-to-Lagrange transformation operator.
Return type:: OperatorABC

Notes

The transformation is carried out by evaluation at the unisolvent nodes; this is not a sparse transformation operator.

__call__(origin_poly=None)#

Transformation of polynomial.

This function is called when an instance of transformation is called T() or T(x). If called without any arguments, the transformation is applied on the origin_poly used to construct the transformation. If an argument is passed, the transformation is applied on the instance passed.

Parameters:: origin_poly (MultivariatePolynomialSingleABC | None) – (optional) an instance of the polynomial to be transformed.
Returns:: an instance of the polynomial in the target basis.

__init__(origin_poly)#

Parameters:: origin_poly (MultivariatePolynomialSingleABC)

classmethod __init_subclass__(**kwargs)#: Add a concrete implementation to the registry of available transformations

__weakref__#: list of weak references to the object (if defined)

_apply_transformation(origin_poly)#

Transforms the polynomial to the target type of the transformation.

Parameters:: origin_poly – instance of the polynomial to be transformed
Returns:: an instance of the transformed polynomial in the target basis

property _target_indices: MultiIndexSet#

The MultiIndexSet of the target_poly.

Returns:: the indices the target polynomial will have

property grid: Grid#: The grid of the origin polynomial.

property multi_index: MultiIndexSet#: The multi index set of the origin polynomial (and also the target polynomial).

property transformation_operator: OperatorABC#

The polynomial basis transformation operator.

Returns:: instance of the transformation operator

Notes

The transformation operator once constructed can be reused for transforming other polynomial instance of the origin_poly type, which have the same basis (and grid) as the origin_poly, to the target_poly type.

class minterpy.transformations.chebyshev.ChebyshevToNewton(origin_poly)[source]#

Bases: TransformationABC

Transformation from the Chebyshev basis to the Newton basis.

Properties

`grid`	The grid of the origin polynomial.
`multi_index`	The multi index set of the origin polynomial (and also the target polynomial).
`transformation_operator`	The polynomial basis transformation operator.

Parameters:: origin_poly (MultivariatePolynomialSingleABC)

origin_type#: alias of ChebyshevPolynomial

target_type#: alias of NewtonPolynomial

_get_transformation_operator()#

Construct the Chebyshev-to-Newton transformation operator.

The transformation is the chain: Chebyshev-to-Lagrange then Lagrange-to-Newton.

Parameters:: transformation (TransformationABC) – The transformer instance with information about the origin polynomial (an instance of ChebyshevPolynomial) and the target type (NewtonPolynomial).
Returns:: The Chebyshev-to-Newton transformation operator.
Return type:: OperatorABC

__call__(origin_poly=None)#

Transformation of polynomial.

This function is called when an instance of transformation is called T() or T(x). If called without any arguments, the transformation is applied on the origin_poly used to construct the transformation. If an argument is passed, the transformation is applied on the instance passed.

Parameters:: origin_poly (MultivariatePolynomialSingleABC | None) – (optional) an instance of the polynomial to be transformed.
Returns:: an instance of the polynomial in the target basis.

__init__(origin_poly)#

Parameters:: origin_poly (MultivariatePolynomialSingleABC)

classmethod __init_subclass__(**kwargs)#: Add a concrete implementation to the registry of available transformations

__weakref__#: list of weak references to the object (if defined)

_apply_transformation(origin_poly)#

Transforms the polynomial to the target type of the transformation.

Parameters:: origin_poly – instance of the polynomial to be transformed
Returns:: an instance of the transformed polynomial in the target basis

property _target_indices: MultiIndexSet#

The MultiIndexSet of the target_poly.

Returns:: the indices the target polynomial will have

property grid: Grid#: The grid of the origin polynomial.

property multi_index: MultiIndexSet#: The multi index set of the origin polynomial (and also the target polynomial).

property transformation_operator: OperatorABC#

The polynomial basis transformation operator.

Returns:: instance of the transformation operator

Notes

The transformation operator once constructed can be reused for transforming other polynomial instance of the origin_poly type, which have the same basis (and grid) as the origin_poly, to the target_poly type.

class minterpy.transformations.chebyshev.ChebyshevToCanonical(origin_poly)[source]#

Bases: TransformationABC

Transformation from the Chebyshev basis to the Canonical basis.

Properties

`grid`	The grid of the origin polynomial.
`multi_index`	The multi index set of the origin polynomial (and also the target polynomial).
`transformation_operator`	The polynomial basis transformation operator.

Parameters:: origin_poly (MultivariatePolynomialSingleABC)

origin_type#: alias of ChebyshevPolynomial

target_type#: alias of CanonicalPolynomial

_get_transformation_operator()#

Construct the Chebyshev-to-Canonical transformation operator.

The transformation is the chain: Chebyshev-to-Lagrange then Lagrange-to-Newton then Newton-to-Canonical.

The Lagrange-to-Canonical is implemented as a single operator.

Parameters:: transformation (TransformationABC) – The transformer instance with information about the origin polynomial (an instance of ChebyshevPolynomial) and the target type (NewtonPolynomial).
Returns:: The Chebyshev-to-Newton transformation operator.
Return type:: OperatorABC

__call__(origin_poly=None)#

Transformation of polynomial.

This function is called when an instance of transformation is called T() or T(x). If called without any arguments, the transformation is applied on the origin_poly used to construct the transformation. If an argument is passed, the transformation is applied on the instance passed.

Parameters:: origin_poly (MultivariatePolynomialSingleABC | None) – (optional) an instance of the polynomial to be transformed.
Returns:: an instance of the polynomial in the target basis.

__init__(origin_poly)#

Parameters:: origin_poly (MultivariatePolynomialSingleABC)

classmethod __init_subclass__(**kwargs)#: Add a concrete implementation to the registry of available transformations

__weakref__#: list of weak references to the object (if defined)

_apply_transformation(origin_poly)#

Transforms the polynomial to the target type of the transformation.

Parameters:: origin_poly – instance of the polynomial to be transformed
Returns:: an instance of the transformed polynomial in the target basis

property _target_indices: MultiIndexSet#

The MultiIndexSet of the target_poly.

Returns:: the indices the target polynomial will have

property grid: Grid#: The grid of the origin polynomial.

property multi_index: MultiIndexSet#: The multi index set of the origin polynomial (and also the target polynomial).

property transformation_operator: OperatorABC#

The polynomial basis transformation operator.

Returns:: instance of the transformation operator

Notes

The transformation operator once constructed can be reused for transforming other polynomial instance of the origin_poly type, which have the same basis (and grid) as the origin_poly, to the target_poly type.