biplotmds.smacofP function

S3 method for smacofP objects

## S3 method for class 'smacofP'
biplotmds(object, extvar, scale = TRUE)

Arguments

• object: An object of class smacofP
• extvar: Data frame with external variables.
• scale: if 'TRUE' external variables are standardized internally.

Returns

Returns an object belonging to classes 'mlm' and 'mdsbi'. See 'lm' for details. R2vec: Vector containing the R2 values. See also biplotmds for the plot method.

Details

If a model for individual differences is provided, the external variables are regressed on the group stimulus space configurations. For objects returned from 'biplotmds' we use the plot method in biplotmds. In the biplot called with plot() only the relative length of the vectors and their direction matters. Using the vecscale argument in plot() the user can control for the relative length of the vectors. If 'vecscale = NULL', the 'vecscale()' function from the 'candisc' package is used which tries to automatically calculate the scale factor so that the vectors approximately fill the same space as the configuration. In this method vecscale should usually be smaller than the one used in smacof by a factor of 0.1.

Examples

## see smacof::biplotmds for more
res <- powerStressMin(morse,kappa=0.5,lambda=2)
fitbi <- biplotmds(res, morsescales[,2:3])
plot(fitbi, main = "MDS Biplot", vecscale = 0.03)