interpprev: Interpolation Using the Previous Value
Description
These functions provide an interpolation mechanism for objects of
class lgtdl. The AsIs method is the vectorized version.
Usage
interpprev(x, ...)
"interpprev"(x, time, cov, ...)
"interpprev"(x, ...)
Arguments
x
x is either an object of class lgtdl or of
class AsIs. It is the object on which interpolation is to be
performed.
time
A vector of times at which interpolation is requested.
cov
The name of the covariate on which interpolation is
requested. It is only required if x has more than one
covariate.
...
Ignored.
Value
interpprev.lgtdl returns a numeric vector of the interpolated
values of the covariate at the time(s) specified by time.
interpprev.AsIs returns a vector of interpolated values of the
covariate. In this case the vector contains one value for each element
x. time must be either the same length as x or
of length one. In the latter case all interpolations are done at that
time.
Details
If objects of class lgtdl are inserted into a data frame they
become a vector with class AsIs. In order to operate on these
we provide a method for that class. The method is simply a vectorized
version.