Glossary of Common Terms#

This glossary contains concepts and API elements specific to the functional data analysis setting or for the package scikit-fda. If the term you are looking is not listed here, it may be a more generally applicable term listed in the scikit-learn Glossary of Common Terms and API Elements.

General Concepts#


The set of allowed output values of a function. Note that the set of actual output values, called the image, can be a strict subset of the codomain.


A functional data object whose domain and codomain are both the set of real numbers (\(\mathbb{R}\)). Thus, its dim_domain and dim_codomain attributes shall both be 1.


The set of possible input values of a function.

domain range#

The valid range where a function can be evaluated. It is a Python sequence that contains, for each dimension of the domain, a tuple with the minimum and maximum values for that dimension. Usually used in plotting functions and as the domain of integration for this function.

Functional Data Analysis#

The branch of statistics that deals with curves, surfaces or other objects varying over a a continuum (functional data objects).

functional data#

A collection of functional data objects. Represented by a FData object.

functional data object#
functional data objects#
functional object#
functional objects#

An object of study of Functional Data Analysis. It is a function between \(\mathbb{R}^p\) and \(\mathbb{R}^q\). Usually represented by a FData object of length 1, but in some cases regular Python callables are also accepted.

functional observation#
functional observations#

An observed functional data object, represented as a FData object of length 1.


The set of actual ouput values that a function takes. It must be a (non necessarily strict) subset of the codomain.

multivariate functional data#

Often used for functional data where each functional data object is a vector-valued function.

multivariate object#
multivariate objects#

An object of study of multivariate statistics. It is a vector of possibly related variables, represented as a 1d array.


Function whose domain is a set of functions.

vector-valued function#

A functional data object that outputs vectors, that is, its codomain has dimension greater than 1.