# loess.control

0th

Percentile

##### Set Parameters for Loess

Set control parameters for loess fits.

Keywords
smooth, loess
##### 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