# fdata2basis: Compute fucntional coefficients from functional data... In fda.usc: Functional Data Analysis and Utilities for Statistical Computing

 fdata2basis R Documentation

## Compute fucntional coefficients from functional data represented in a base of functions

### Description

Compute fucntional coefficients from functional data (`fdata` class object) represented in a basis (fixed of data-driven basis).

### Usage

```fdata2basis(fdataobj, basis, method = c("grid", "inprod"))

## S3 method for class 'basis.fdata'
summary(object, draw = TRUE, index = NULL, ...)
```

### Arguments

 `fdataobj` `fdata` class object. `basis` a functional basis object defining the basis `method` character string, if it is "grid" the fdata object is evaluated in the grid (`argvals` of fdata), if it is "inprod" the basis representation of functional data is computed by inner product (`inprod.fdata(fdataobj,basis)`). `object` `basis.fdata` class object calculated by: `fdata2basis` `draw` logical, original curves and their basis representation are plotted `index` vector, by default (if NULL) the first n curves are plotted, where n = min(4, length(fdataobj)). Otherwise, index vector indicates taht curvesare plotted. `...` Further arguments passed to or from other methods.

### Value

fdata2basis `fdata2bais` function return:

• coefa matrix or two-dimensional array of coefficients.

• basisbasis of `fdata` class evaluated in the same grid of `fdataobj`.

summary function return:

• Ra matrix with a measure similar to R-sq for each curve aproximation (by row) and number of basis elements (by column).

### Author(s)

Manuel Febrero-Bande, Manuel Oviedo de la Fuente manuel.oviedo@usc.es

Inverse function: `gridfdata`. Alternative method: `fdata2pc`, `fdata2pls`.

### Examples

```## Not run:
T <- 71
S <- 51
tj <- round(seq(0,1,len=T),3)
si <- round(seq(0,1,len=S),3)
beta1 <- outer(si,tj,function(si,tj){exp(-5*abs((tj-si)/5))})
nbasis.s =7
nbasis.t=11
base.s <- create.fourier.basis(c(0,1),nbasis=nbasis.s)
base.t <- create.fourier.basis(c(0,1),nbasis=nbasis.t)
y1 <- fdata(rbind(log(1+tj),1-5*(tj-0.5)^2),argvals=tj,rangeval=c(0,1))
aa <- fdata2basis(y1,base.t,method="inprod")
summary(aa)
plot(gridfdata(aa\$coefs,aa\$basis))
lines(y1,lwd=2,col=c(3,4),lty=2)

## End(Not run)
```

fda.usc documentation built on Oct. 17, 2022, 9:06 a.m.