stress0 function

Zero-Iterations Stress

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

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.

Returns

• 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)