stop_sstress: STOPS version of sstress

In stops: Structure Optimized Proximity Scaling

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 factor of 2 (as sstress has f(delta^2), so we do f(delta^(2*lambda))).

Usage

stop_sstress(
  dis,
  theta = 1,
  type = type,
  weightmat = 1 - diag(nrow(dis)),
  init = NULL,
  ndim = 2,
  itmaxi = 10000,
  acc = 1e-08,
  ...,
  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"),
  registry = struc_reg
)

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 factor 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
acc	accuracy (default is 1e-8)
...	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'
registry	registry object with c-structuredness indices.

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

stops documentation built on July 7, 2025, 3:01 p.m.