validate.covariance.model: Validate the structure of the covariance model
Description
Check that a matrix corresponds to a structure defining a covariance model for a non-linear mixed effect model.
Such a matrix should be composed of only 0s and 1s, with at least one element set to 1, and should be square and symmetrical.
1s on the diagonal indicate that the corresponding parameter has interindividual variability and that its variance will be estimated.
1s as off-diagonal elements indicate that a covariance between the two corresponding parameters will be estimated.
Usage
validate.covariance.model(x, verbose = TRUE)
Value
a boolean, TRUE if x is an acceptable structure and FALSE if not. Messages will be output to describe why x isn't a valid covariance model if the argument verbose is TRUE.
Arguments
x
a matrix
verbose
a boolean indicating whether warnings should be output if x is not a valid covariance model