| place.knots {mgcv} | R Documentation |
Automatically place a set of knots evenly through covariate values
Description
Given a univariate array of covariate values, places a set of knots for a regression spline evenly through the covariate values.
Usage
place.knots(x,nk)
Arguments
x |
array of covariate values (need not be sorted). |
nk |
integer indicating the required number of knots. |
Details
Places knots evenly throughout a set of covariates. For example, if you had 11 covariate values and wanted 6 knots then a knot would be placed at the first (sorted) covariate value and every second (sorted) value thereafter. With less convenient numbers of data and knots the knots are placed within intervals between data in order to achieve even coverage, where even means having approximately the same number of data between each pair of knots.
Value
An array of knot locations.
Author(s)
Simon N. Wood simon.wood@r-project.org
References
https://www.maths.ed.ac.uk/~swood34/
See Also
smooth.construct.cc.smooth.spec
Examples
require(mgcv)
x<-runif(30)
place.knots(x,7)
rm(x)