# right: One-sided right smooth for a Locfit model. In locfit: Local Regression, Likelihood and Density Estimation

## Description

The `right()` function is used in a locfit model formula to specify a one-sided smooth: when fitting at a point x, only data points with x_i ≤ x should be used. This can be useful in estimating points of discontinuity, and in cross-validation for forecasting a time series. `right(x)` is equivalent to `lp(x,style="right")`.

When using this function, it will usually be necessary to specify an evaluation structure, since the fit is not smooth and locfit's interpolation methods are unreliable. Also, it is usually best to use `deg=0` or `deg=1`, otherwise the fits may be too variable. If nearest neighbor bandwidth specification is used, it does not recognize `right()`.

## Usage

 `1` ```right(x,...) ```

## Arguments

 `x` numeric variable. `...` Other arguments to `lp()`.

`locfit`, `left`

## Examples

 ```1 2 3 4 5 6 7``` ```# compute left and right smooths data(penny) xev <- (1945:1988)+0.5 fitl <- locfit(thickness~left(year,h=10,deg=1), ev=xev, data=penny) fitr <- locfit(thickness~right(year, h=10, deg=1), ev=xev, data=penny) # plot the squared difference, to show the change points. plot( xev, (predict(fitr, where="ev") - predict(fitl, where="ev"))^2 ) ```

### Example output

```locfit 1.5-9.4 	 2020-03-24
```

locfit documentation built on March 25, 2020, 5:07 p.m.