sammonmap: Sammon Mapping SMACOF

In smacofx: Flexible Multidimensional Scaling and 'smacof' Extensions

Sammon Mapping SMACOF

Description

An implementation to minimize Sammon stress by majorization with ratio and interval optimal scaling. Uses a repeat loop.

Usage

sammonmap(
  delta,
  type = c("ratio", "interval"),
  weightmat,
  init = NULL,
  ndim = 2,
  acc = 1e-06,
  itmax = 10000,
  verbose = FALSE,
  principal = FALSE
)

Arguments

delta	dist object or a symmetric, numeric data.frame or matrix of distances
type	what type of MDS to fit. Currently one of "ratio" and "interval". Default is "ratio".
weightmat	a matrix of finite weights
init	starting configuration
ndim	dimension of the configuration; defaults to 2
acc	numeric accuracy of the iteration. Default is 1e-6.
itmax	maximum number of iterations. Default is 10000.
verbose	should iteration output be printed; if > 1 then yes
principal	If 'TRUE', principal axis transformation is applied to the final configuration

Value

a 'smacofP' object (inheriting from smacofB, see smacofSym). It is a list with the components

• delta: Observed dissimilarities

• tdelta: Observed explicitly transformed dissimilarities, normalized

• dhat: Observed dissimilarities (dhats), optimally scaled and normalized

• confdist: Transformed configuration distances

• conf: Matrix of fitted configuration

• stress: Default stress (stress 1; sqrt of explicitly normalized stress)

• spp: Stress per point (based on stress.en)

• ndim: Number of dimensions

• model: Name of smacof model

• niter: Number of iterations

• nobj: Number of objects

• type: Type of MDS model

• weightmat: weighting matrix as supplied

• stress.m: default stress (stress-1^2)

• tweightmat: weighting matrix atfer transformation (here weightmat/delta)

See Also

rStressMin

Examples

dis<-smacof::kinshipdelta
res<-sammonmap(as.matrix(dis),itmax=1000)
res
summary(res)
plot(res)

smacofx documentation built on Sept. 22, 2024, 5:07 p.m.