Structural equation modeling in R(lavaan,sem)

Daer all, I have a question concerning longitudinal data: When we
have a longitudinal data and we have to do sem analysis there is in
the package lavaan some functions,options in this package that help
to do this or we can treat these data like non longitudinal data

The function 'growth' (in the lavaan package) can be used for (standard) 
growth modeling. Good material about growth modeling (using Mplus) can 
be found here:

http://statistics.ats.ucla.edu/stat/mplus/seminars/gm/default.htm

Next, you can read how to do growth modeling with lavaan by reading 
section 7 in the lavaan intro, which you can download from the 
documentation section on the lavaan website (http://lavaan.org).

Yves.

Yves Rosseel -- http://www.da.ugent.be
Department of Data Analysis, Ghent University
Henri Dunantlaan 1, B-9000 Gent, Belgium