rpowerStressMin {smacofx}

Restricted Power Stress SMACOF

Description

An implementation to minimize restricted power stress by majorization with ratio or interval optimal scaling. Restricted means that the same power is used for both dissimilarities and fitted distances. Uses a repeat loop.

Usage

rpowerStressMin(
  delta,
  expo = 1,
  nu = 1,
  type = "ratio",
  weightmat,
  init = NULL,
  ndim = 2,
  acc = 1e-06,
  itmax = 10000,
  verbose = FALSE,
  principal = FALSE
)

rpowerstressMin(
  delta,
  expo = 1,
  nu = 1,
  type = "ratio",
  weightmat,
  init = NULL,
  ndim = 2,
  acc = 1e-06,
  itmax = 10000,
  verbose = FALSE,
  principal = FALSE
)

rpostmds(
  delta,
  expo = 1,
  nu = 1,
  type = "ratio",
  weightmat,
  init = NULL,
  ndim = 2,
  acc = 1e-06,
  itmax = 10000,
  verbose = FALSE,
  principal = FALSE
)

rpstressMin(
  delta,
  expo = 1,
  nu = 1,
  type = "ratio",
  weightmat,
  init = NULL,
  ndim = 2,
  acc = 1e-06,
  itmax = 10000,
  verbose = FALSE,
  principal = FALSE
)

rpStressMin(
  delta,
  expo = 1,
  nu = 1,
  type = "ratio",
  weightmat,
  init = NULL,
  ndim = 2,
  acc = 1e-06,
  itmax = 10000,
  verbose = FALSE,
  principal = FALSE
)

rpstressmds(
  delta,
  expo = 1,
  nu = 1,
  type = "ratio",
  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

expo

power of the transformation of the fitted distances and dissimilarities; defaults to 1

nu

the power of the transformation for weightmat; defaults to 1

type

what type of MDS to fit. One of "ratio" or "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, untransformed dissimilarities

• tdelta: Observed explicitly transformed dissimilarities, normalized

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

• confdist: Configuration dissimilarities

• conf: Matrix of fitted configuration

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

• spp: Stress per point

• 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: transformed weighthing matrix (here weightmat^nu)

• parameters, pars, theta: The parameter vector of the explicit transformations

Examples

dis<-smacof::kinshipdelta
res<-rpowerStressMin(as.matrix(dis),expo=1.7,itmax=1000)
res
summary(res)
plot(res)