Facilitate centering covariates

The motivation for this is to obtain confidence intervals for
covariate dependent parameters that are valid for a median/mean
value of the covariate.

Implementation by adding an argument to the 'saem' function, and
adapting the relevant functions working with 'saem' objects.

Vignettes, the template and tests were updated to use the new functionality.

1 files changed, 5 insertions, 0 deletions

diff --git a/man/saem.Rd b/man/saem.Rd
index fd19fe59..5d42f1b1 100644
--- a/man/saem.Rd
+++ b/man/saem.Rd
@@ -22,6 +22,7 @@ saem(object, ...)
   omega.init = "auto",
   covariates = NULL,
   covariate_models = NULL,
+  center_covariates = c(NA, "median", "mean"),
   no_random_effect = NULL,
   error.init = c(1, 1),
   nbiter.saemix = c(300, 100),
@@ -101,6 +102,10 @@ initialisation of \link[saemix:saemixModel]{saemix::saemixModel} is used for ome
 variable, i.e. of the type 'parameter ~ covariate'. Covariates must be available
 in the 'covariates' data frame.}
 
+\item{center_covariates}{Either NA, for no centering, or your
+preferred function for calculating the center, currently either
+median or mean.}
+
 \item{no_random_effect}{Character vector of degradation parameters for
 which there should be no variability over the groups. Only used
 if the covariance model is not explicitly specified.}