# 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.

### References

Ramsay, James O., Hooker, Giles, and Graves, Spencer (2009), Functional data analysis with R and Matlab, Springer, New York.

Ramsay, James O., and Silverman, Bernard W. (2005), Functional Data Analysis, 2nd ed., Springer, New York.

Ramsay, James O., and Silverman, Bernard W. (2002), Applied Functional Data Analysis, Springer, New York.

`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 May 29, 2024, 11:26 a.m.