stress0 {smacof}

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)