cop_elastic function

PCOPS versions of elastic scaling models (via smacofSym)

The free parameter is lambda for power transformations the observed proximities. The fitted distances power is internally fixed to 1 and the power for the weights=delta is -2. Allows for a weight matrix because of smacof.

cop_elastic(
  dis,
  theta = 1,
  type = "ratio",
  ndim = 2,
  weightmat = 1 - diag(nrow(dis)),
  init = NULL,
  itmaxi = 1000,
  ...,
  stressweight = 1,
  cordweight = 0.5,
  q = 1,
  minpts = ndim + 1,
  epsilon = 10,
  rang = NULL,
  verbose = 0,
  normed = TRUE,
  scale = "sd"
)

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.
• type: MDS type.
• ndim: number of dimensions of the target space
• weightmat: (optional) a matrix of nonnegative weights (NOT the elscal weights)
• init: (optional) initial configuration
• itmaxi: number of iterations. default is 1000.
• ...: additional arguments to be passed to the fitting procedure
• stressweight: weight to be used for the fit measure; defaults to 1
• cordweight: weight to be used for the cordillera; defaults to 0.5
• q: the norm of the corrdillera; defaults to 1
• minpts: the minimum points to make up a cluster in OPTICS; defaults to ndim+1
• epsilon: the epsilon parameter of OPTICS, the neighbourhood that is checked; defaults to 10
• rang: range of the distances (min distance minus max distance). If NULL (default) the cordillera will be normed to each configuration's maximum distance, so an absolute value of goodness-of-clusteredness.
• verbose: numeric value hat prints information on the fitting process; >2 is extremely verbose
• normed: should the cordillera be normed; defaults to TRUE
• scale: should the configuration be scale adjusted

Returns

A list with the components

• stress: the stress-1
• stress.m: default normalized stress
• copstress: the weighted loss value
• OC: the Optics cordillera value
• parameters: the parameters used for fitting (lambda)
• fit: the returned object of the fitting procedure (plus a slot for the orginal data $deltaorig)
• cordillera: the cordillera object