loess.control {modreg}  R Documentation 
Set control parameters for loess
fits.
loess.control(surface = c("interpolate", "direct"), statistics = c("approximate", "exact"), trace.hat = c("exact", "approximate"), cell = 0.2, iterations = 4, ...)
surface 
should be fitted surface be computed exactly or via interpolation from a kd tree? 
statistics 
should the statistics be computed exactly or approximately? Exact computation can be very slow. 
trace.hat 
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. 
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. 
... 
further arguments which are ignored. 
A list with components
surface 

statistics 

trace.hat 

cell 

iterations 
with meanings as explained under ‘Arguments’.