# coef: Extract functional coefficients In fda: Functional Data Analysis

 coef.fd R Documentation

## Extract functional coefficients

### Description

Obtain the coefficients component from a functional object (functional data, class `fd`, functional parameter, class `fdPar`, a functional smooth, class `fdSmooth`, or a Taylor spline representation, class `Taylor`.

### Usage

```## S3 method for class 'fd'
coef(object, ...)
## S3 method for class 'fdPar'
coef(object, ...)
## S3 method for class 'fdSmooth'
coef(object, ...)
## S3 method for class 'fd'
coefficients(object, ...)
## S3 method for class 'fdPar'
coefficients(object, ...)
## S3 method for class 'fdSmooth'
coefficients(object, ...)
```

### Arguments

 `object` An object whose functional coefficients are desired `... ` other arguments

### Details

Functional representations are evaluated by multiplying a basis function matrix times a coefficient vector, matrix or 3-dimensional array. (The basis function matrix contains the basis functions as columns evaluated at the `evalarg` values as rows.)

### Value

A numeric vector or array of the coefficients.

`coef` `fd` `fdPar` `smooth.basisPar` `smooth.basis`

### Examples

```##
## coef.fd
##
bspl1.1 <- create.bspline.basis(norder=1, breaks=0:1)
fd.bspl1.1 <- fd(0, basisobj=bspl1.1)
coef(fd.bspl1.1)

##
## coef.basisPar
##
rangeval <- c(-3,3)
#  set up some standard normal data
x <- rnorm(50)
#  make sure values within the range
x[x < -3] <- -2.99
x[x >  3] <-  2.99
#  set up basis for W(x)
basisobj <- create.bspline.basis(rangeval, 11)
#  set up initial value for Wfdobj
Wfd0 <- fd(matrix(0,11,1), basisobj)
WfdParobj <- fdPar(Wfd0)

coef(WfdParobj)

##
## coef.fdSmooth
##

girlGrowthSm <- with(growth, smooth.basisPar(argvals=age, y=hgtf,
lambda=0.1)\$fd)
coef(girlGrowthSm)

```

fda documentation built on April 27, 2022, 1:07 a.m.