Make a list of spans
makeSpanList(SMatrix, Sse)
S matrix from the ram matrices
Standard error matrix for S matrix from the ram matrices
Boker, S. M., McArdle, J. J. & Neale, M. C. (2002) An algorithm for the hierarchical organization of path diagrams and calculation of components of covariance between variables. Structural Equation Modeling, 9(2), 174-194
Zhang, Z., Hamagami, F., Grimm, K. J., & McArdle, J. J. (2015). Using R package RAMpath for tracing SEM path diagrams and conducting complex longitudinal data analysis. Structural Equation Modeling, 22(1), 132-147. https://doi.org/10.1080/10705511.2014.935257