ddalpha: dataf2rawfd – R documentation

Become an expert in R — Interactive courses, Cheat Sheets, certificates and more!

dataf2rawfd

Transform a dataf Object to Raw Functional Data

Description

From a (possibly multivariate) functional data object dataf constructs an array of the functional values evaluated at an equi-distant grid of points.

Usage

dataf2rawfd(dataf, range = NULL, d = 101)

Arguments

`dataf`	Functions to be transformed, represented by a (possibly multivariate) `dataf` object of their arguments and functional values. `m` stands for the number of functions. The grid of observation points for the functions in `dataf` may not be the same.
`range`	The common range of the domain where the functions `dataf` are observed. Vector of length 2 with the left and the right end of the interval. Must contain all arguments given in `dataf`. If the range is not provided, the smallest interval in which all the arguments from the data functions are contained is chosen as the domain.
`d`	Grid size to which all the functional data are transformed. All functional observations are transformed into vectors of their functional values of length `d` corresponding to equi-spaced points in the domain given by the interval `range`. Functional values in these points are reconstructed using linear interpolation, and extrapolation, see Nagy et al. (2016).

Value

If the functional data are univariate (scalar-valued), a matrix of size m*d is given, with each row corresponding to one function. If the functional data are k-variate with k>1, an array of size m*d*k of the functional values is given.

Author(s)

Stanislav Nagy, nagy at karlin.mff.cuni.cz

Examples

## transform a matrix into a functional data set and back
n = 5
d = 21
X = matrix(rnorm(n*d),ncol=d)
R = rawfd2dataf(X,range=c(0,1))
R2 = dataf2rawfd(R,range=c(0,1),d=d)
all.equal(X,R2)

## transform a functional dataset into a raw matrix of functional values
dataf = dataf.population()$dataf
dataf2rawfd(dataf,range=c(1950,2015),d=66)

## transform an array into a multivariate functional data set and back
k = 3
X = array(rnorm(n*d*k),dim=c(n,d,k))
R = rawfd2dataf(X,range=c(-1,1))
dataf2rawfd(R,range=c(-1,1),d=50)

ddalpha

Depth-Based Classification and Calculation of Data Depth

v1.3.11

GPL-2

Authors

Oleksii Pokotylo [aut, cre], Pavlo Mozharovskyi [aut], Rainer Dyckerhoff [aut], Stanislav Nagy [aut]

Initial release

2020-01-09