loess.control {stats} R Documentation

## Set Parameters for Loess

### Description

Set control parameters for loess fits.

### Usage

loess.control(surface = c("interpolate", "direct"),
statistics = c("approximate", "exact", "none"),
trace.hat = c("exact", "approximate"),
cell = 0.2, iterations = 4, iterTrace = FALSE, ...)


### Arguments

 surface should the fitted surface be computed exactly ("direct") or via interpolation from a kd tree? Can be abbreviated. statistics should the statistics be computed exactly, approximately or not at all? Exact computation can be very slow. Can be abbreviated. trace.hat Only for the (default) case (surface = "interpolate", statistics = "approximate"): should the trace of the smoother matrix be computed exactly or approximately? It is recommended to use the approximation for more than about 1000 data points. Can be abbreviated. cell if interpolation is used this controls the accuracy of the approximation via the maximum number of points in a cell in the kd tree. Cells with more than floor(n*span*cell) points are subdivided. iterations the number of iterations used in robust fitting, i.e. only if family is "symmetric". iterTrace logical (or integer) determining if tracing information during the robust iterations (iterations\ge 2) is produced. ... further arguments which are ignored.

### Value

A list with components

 surface statistics trace.hat cell iterations iterTrace

with meanings as explained under ‘Arguments’.

loess