| gettvc {rmutil} | R Documentation |
gettvc finds the most recent value of a time-varying covariate
before each observed response and possibly adds them to a list of other
time-varying covariates.
It compares the times of response observations with those of
time-varying covariates to find the most recent observed time-varying
covariate for each response. These are either placed in a new object of
class, tvcov, added to an already existing list of matrices containing
other time-varying covariates and a new object of class, tvcov,
created, or added to an existing object of class, tvcov.
If there are response observation times before the first covariate time, the covariate for these times is set to zero.
gettvc(response, times=NULL, tvcov=NULL, tvctimes=NULL,
oldtvcov=NULL, ties=TRUE)
response |
A list of two column matrices with response values and
times for each individual, one matrix or dataframe of response
values, or an object of class, response (created by
restovec). |
times |
When response is a matrix, a vector of possibly
unequally spaced times for the response, when they are the same for
all individuals or a matrix of times. Not necessary if equally spaced. |
tvcov |
A list of two column matrices with time-varying covariate values and corresponding times for each individual or one matrix or dataframe of such covariate values. Times need not be the same as for responses. |
tvctimes |
When the time-varying covariate is a matrix, a vector of possibly unequally spaced times for the covariate, when they are the same for all individuals or a matrix of times. Not necessary if equally spaced. |
oldtvcov |
A list of matrices with time-varying covariate values,
observed at the event times in response, for each individual,
or an object of class, tvcov. If not provided, a new object is
created. |
ties |
If TRUE, when the response and covariate times are identical, the response depends on that new value (as in observational studies); if FALSE, only the next response depends on that value (for example, if the covariate is a new treatment just applied at that time). |
An object of class, tvcov, is returned containing the new time-varying
covariate and, possibly, those in oldtvcov.
J.K. Lindsey and D.F. Heitjan
carma, elliptic,
gar, kalcount,
kalseries, kalsurv,
read.list, restovec,
tvctomat.
y <- matrix(rnorm(20), ncol=5) resp <- restovec(y, times=c(1,3,6,10,15)) z <- matrix(rpois(20,5),ncol=5) z # create a new time-varying covariate object for the response newtvc <- gettvc(resp, tvcov=z, tvctimes=c(1,2,5,12,14)) covariates(newtvc) # add another time-varying covariate to the object z2 <- matrix(rpois(20,5),ncol=5) z2 newtvc2 <- gettvc(resp, tvcov=z2, tvctimes=c(0,4,5,12,16), oldtvc=newtvc) covariates(newtvc2)