| semds {semds} | R Documentation |
Structural Equation Multidimensional Scaling
Description
Fits a multidimensional scaling (MDS) model on asymmetric dissimilarity data and three-way data. It uses an alternating estimation procedure in which the unknown symmetric dissimilarity matrix is estimated in a structural equation modeling (SEM) framework while the objects are represented in a low-dimensional space.
Usage
semds(D, dim = 2, saturated = FALSE, theta0 = NULL, maxiter = 1000, eps = 1e-06)
Arguments
D |
A list of input dissimilarity matrices for the general multiway case. For the special 2-way case it can also be a single asymmetric dissimilarity matrix. |
dim |
Number of dimensions for MDS solution. |
saturated |
For the 2-way case only: whether the model is saturated (TRUE) or not (FALSE; default). |
theta0 |
Starting values for SEM parameter vector. |
maxiter |
Maximum number of iterations. |
eps |
Convergence criterion for difference of subsequent stress values. |
Details
Add details
Value
Returns an object of class "semds" containing the following elements.
stressnorm |
Normalized stress value. |
stressraw |
Raw stress value. |
Delta |
Disparity matrix. |
theta |
SEM parameter vector. |
conf |
MDS configurations. |
dist |
Distance matrix based on configurations |
niter |
Number of iterations. |
thetatab |
Parameter table. |
call |
Function call. |
Author(s)
Patrick Mair, Jose Fernando Vera
References
Vera, J. F. & Rivera, C. D. (2014). A structural equation multidimensional scaling model for one-mode asymmetric dissimilarity data. Structural Equation Modeling: A Multidisciplinary Journal, 21(1), 54–62.
Examples
## asymmetric model
fit2way <- semds(Miller)
fit2way
summary(fit2way)
plot(fit2way)
## asymmetric model (saturated)
fit2wayS <- semds(Miller, saturated = TRUE)
fit2wayS
fit2wayS$theta
## general three-way model
fitmway <- semds(BrahmsNorm)
fitmway
summary(fitmway)
plot(fitmway)