stress0: Zero-Iterations Stress

In smacof: Multidimensional Scaling

Zero-Iterations Stress

Description

Computes the stress for 0 iterations based on a starting configuration provided by the user.

Usage

stress0(delta, init, type = c("interval", "ratio", "ordinal", "mspline"), 
        weightmat = NULL, ties = "primary", spline.degree = 2, spline.intKnots = 2)

Arguments

delta	Either a symmetric dissimilarity matrix or an object of class "dist"
init	An initial configuration provided by the user
weightmat	Optional matrix with dissimilarity weights
type	MDS type: "interval", "ratio", "ordinal" (nonmetric MDS), or "mspline"
ties	Tie specification (ordinal MDS only): "primary", "secondary", or "tertiary"
spline.degree	Degree of the spline for "mspline" MDS type
spline.intKnots	Number of interior knots of the spline for "mspline" MDS type

Details

Computes stress-1 for a particular starting configuration the user needs to provide. It can also be helpful if the user wants to force a particular theoretical configuration (as specified in inits) on the data.

Value

delta	Observed dissimilarities, not normalized
dhat	Disparities (transformed proximities, approximated distances, d-hats)
confdist	Configuration distances
conf	Matrix of fitted configurations
stress	Stress-1 value
spp	Stress per point (stress contribution in percentages)
resmat	Matrix with squared residuals
rss	Residual sum-of-squares
weightmat	Weight matrix
ndim	Number of dimensions
init	Starting configuration
model	Name of smacof model
niter	Number of iterations
nobj	Number of objects
type	Type of MDS model

See Also

mds

Examples

## rectangle starting solution
rect_constr
stress0(rectangles, init = rect_constr)

## torgerson starting solution
tstart <- torgerson(rectangles)
stress0(rectangles, init = tstart)

smacof documentation built on Oct. 10, 2024, 5:09 p.m.