semds: Structural Equation Multidimensional Scaling

In semds: 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)

semds documentation built on May 2, 2019, 6:34 p.m.