# density.lf: Density estimation using Locfit In locfit: Local Regression, Likelihood and Density Estimation

 density.lf R Documentation

## Density estimation using Locfit

### Description

This function provides an interface to Locfit, in the syntax of (a now old version of) the S-Plus `density` function. This can reproduce `density` results, but allows additional `locfit.raw` arguments, such as the degree of fit, to be given.

It also works in double precision, whereas `density` only works in single precision.

### Usage

```density.lf(x, n = 50, window = "gaussian", width, from, to,
cut = if(iwindow == 4.) 0.75 else 0.5,
ev = lfgrid(mg = n, ll = from, ur = to),
deg = 0, family = "density", link = "ident", ...)
```

### Arguments

 `x` numeric vector of observations whose density is to be estimated. `n` number of evaluation points. Equivalent to the `locfit.raw mg` argument. `window` Window type to use for estimation. Equivalent to the `locfit.raw kern` argument. This includes all the `density` windows except `cosine`. `width` Window width. Following `density`, this is the full width; not the half-width usually used by Locfit and many other smoothers. `from` Lower limit for estimation domain. `to` Upper limit for estimation domain. `cut` Controls default expansion of the domain. `ev` Locfit evaluation structure – default `lfgrid()`. `deg` Fitting degree – default 0 for kernel estimation. `family` Fitting family – default is `"density"`. `link` Link function – default is the `"identity"`. `...` Additional arguments to `locfit.raw`, with standard defaults.

### Value

A list with components `x` (evaluation points) and `y` (estimated density).

`density`, `locfit`, `locfit.raw`

### Examples

```data(geyser)
density.lf(geyser, window="tria")
# the same result with density, except less precision.
density(geyser, window="tria")
```

locfit documentation built on March 18, 2022, 6:48 p.m.