stop_sstress function

STOPS version of sstress

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)).

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"),
  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 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'
• registry: registry object with c-structuredness indices.

Returns

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