Model functions

spl() function

spl(v[,k]) and s(v[,k])
In order to fit spline models associated with a variate v and k knot points in ASRSeml, v is included as a covariate in the model as a fixed term and spl(v,k) as a random term. The knot points can be explicitly specified using the !SPLINE qualifier. If k is specified but !SPLINE is not specified, equally spaced points are used. If k is not specified and there are less than 50 unique data values, they are used as knot points. If there are more than 50 unique points then 50 equally spaced points will be used. The spline design matrix formed is written to the .res file. An example of the use of spl() is
price ~ mu week !r spl(week)

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