analogue (version 0.17-4)

scores.prcurve: scores method for principal curve objects of class "prcurve".

Description

A scores method to extract the position on the curve to which each observation projects (display = "curve") or the coordinates of the curve in the dimensions of the input data (display = "dimensions").

Usage

# S3 method for prcurve
scores(x, display = c("curve", "dimensions"), ...)

Arguments

x

an object of class "prcurve", usually from a call to prcurve.

display

character; which type of scores to extract. display = "curve" returns the position along the curve onto which each observation projects; this can be used like a PCA axis score. display = "dimensions" returns the coordinates of the curve in the dimensions of the original data.

…

Arguments passed to other methods. Not used.

Value

If display = "curve" a 1-column matrix is returned with a row for each observation in the input data. If display = "dimensions", a matrix of coordinates for the principal curve is returned. The dimensions of this matrix relate to the dimensions of the input data; if there were \(n\) samples (rows) and \(m\) variables columns then the matrix returned by scores.prcurve will have \(n\) rows and \(m\) columns.

See Also

prcurve for fitting principal curves to data.

Examples

# NOT RUN {
## Load the Abernethy Forest data set
data(abernethy)

## Remove the Depth and Age variables
abernethy2 <- abernethy[, -(37:38)]

## Fit the principal curve using varying complexity of smoothers
## for each species
aber.pc <- prcurve(abernethy2, method = "ca", trace = TRUE,
                   vary = TRUE, penalty = 1.4)

## Extract position on the curve
pos <- scores(aber.pc, display = "curve")
head(pos)

## Extract the coordinates of the curve
coord <- scores(aber.pc, display = "dimensions")
dim(coord)
all.equal(dim(coord), dim(abernethy2))
# }