R: Evaluate the Diagonal of a Bivariate Functional Data Object

evaldiag.bifd {fda} | R Documentation

## Evaluate the Diagonal of a Bivariate Functional Data Object

### Description

Bivariate function data objects are functions of two arguments, $f(s,t)$. It can be useful to evaluate the function for argument values satisying $s=t$, such as evaluating the univariate variance function given the bivariate function that defines the variance-covariance function or surface. A linear differential operator can be applied to function $f(s,t)$ considered as a univariate function of either object holding the other object fixed.

### Usage

    evaldiag.bifd(evalarg, bifdobj, sLfd=int2Lfd(0),
                                    tLfd=int2Lfd(0), returnMatrix=FALSE)

### Arguments

`evalarg` | a vector of values of $s = t$.
`bifdobj` | a bivariate functional data object of the `bifd` class.
`sLfd` | either a nonnegative integer or a linear differential operator object.
`tLfd` | either a nonnegative integer or a linear differential operator object.
`returnMatrix` | logical: If TRUE, a two-dimensional is returned using a special class from the Matrix package.

### Value

a vector or matrix of diagonal function values.

### See Also

`var.fd`, `eval.bifd`

[Package fda version 2.4.8 Index]