needUpdate.modelStruct: Check if a modelStruct Object Needs Updating
Description
This method function checks if any of the elements of object
needs to be updated. Updating of objects usually takes place in
iterative algorithms in which auxiliary quantities associated with the
object, and not being optimized over, may change.
Usage
## S3 method for class 'modelStruct':
needUpdate(object)
Arguments
object
an object inheriting from class modelStruct,
representing a list of model components, such as corStruct and
varFunc objects.
Value
a logical value indicating whether any element of object needs
to be updated.