Objects from the Class
Objects can be created by calls of the form new("gmData",
varNames, varTypes, numberLevels, latent, valueLabels,
observations).
A gmData object contains the abstraction of data into a
meta data object including variable names and types etc. However, the
actual data might not be present or may be represented by a reference
to data, such as a database file. Also, it may be possible to work
without data, which may be valuable if the point of interest is in the
model alone. Separating the specification of the
variables from data has the benefit, that some properties of a model can be
investigated without any reference to data, for example
decomposability and collapsibility.