stop_sstress {stops}

STOPS version of sstress

Description

Free parameter is lambda for the observed proximities. Fitted distances are transformed with power 2, weights have exponent of 1. Note that the lambda here works as a multiplicator of 2 (as sstress has f(delta^2)).

Usage

stop_sstress(
  dis,
  theta = 1,
  type = type,
  weightmat = 1 - diag(nrow(dis)),
  init = NULL,
  ndim = 2,
  itmaxi = 1e+05,
  ...,
  stressweight = 1,
  structures = c("cclusteredness", "clinearity", "cdependence", "cmanifoldness",
    "cassociation", "cnonmonotonicity", "cfunctionality", "ccomplexity", "cfaithfulness",
    "cregularity", "chierarchy", "cconvexity", "cstriatedness", "coutlying",
    "cskinniness", "csparsity", "cstringiness", "cclumpiness", "cinequality"),
  strucweight = rep(1/length(structures), length(structures)),
  strucpars,
  verbose = 0,
  stoptype = c("additive", "multiplicative")
)

Arguments

dis

numeric matrix or dist object of a matrix of proximities

theta

the theta vector of powers; this must be a scalar of the lambda transformation for the observed proximities. Defaults to 1. Note that the lambda here works as a multiplicator of 2 (as sstress has f(delta^2)).

type

MDS type.

weightmat

(optional) a matrix of nonnegative weights

init

(optional) initial configuration

ndim

the number of dimensions of the target space

itmaxi

number of iterations

...

additional arguments to be passed to the fitting procedure

stressweight

weight to be used for the fit measure; defaults to 1

structures

which structuredness indices to be included in the loss

strucweight

weight to be used for the structuredness indices; ; defaults to 1/#number of structures

strucpars

the parameters for the structuredness indices

verbose

numeric value hat prints information on the fitting process; >2 is extremely verbose

stoptype

How to construct the target function for the multi objective optimization? Either 'additive' (default) or 'multiplicative'

Value

A list with the components

• stress: the stress-1 value

• stress.m: default normalized stress

• stoploss: the weighted loss value

• indices: the values of the structuredness indices

• parameters: the parameters used for fitting (lambda)

• fit: the returned object of the fitting procedure

• stopobj: the stopobj object