penalized.pls.select {ppls}R Documentation

Penalized PLS based on NIPALS Algorithm and blockswise variable selection

Description

Internal function that computes the penalized PLS solutions with included block-wise variable selection.

Usage

penalized.pls.select(X, y, M, ncomp,blocks)

Arguments

X matrix of centered and (possibly) scaled input data
y vector of centered and (possibly) scaled response data
M matrix that is a transformation of the penalty term P. Default is M=NULL, which corresponds to no penalization.
ncomp number of PLS components
blocks vector of length ncol(X) that encodes the block structure of X.

Details

This function assumes that the columns of X and y are centered and - optionally - scaled. The matrix M is defined as the inverse of (I + P) . The computation of the regression coefficients is based on an extension of the classical NIPALS algorithm for PLS. Moreover, in each iteration, the weight vector is only defined by one block of variables. For more details, see Kr"amer, Boulesteix, and Tutz (2008).

Value

coefficients Penalized PLS coefficients for all 1,2,...,ncomp components

Note

This is an internal function that is called by penalized.pls.

Author(s)

Nicole Kr"amer

References

N. Kr"amer, A.-L. Boulsteix, and G. Tutz (2008). Penalized Partial Least Squares with Applications to B-Spline Transformations and Functional Data. Chemometrics and Intelligent Laboratory Systems, 94, 60 - 69.

See Also

penalized.pls, ppls.splines.cv

Examples

# this is an internal function

[Package ppls version 1.03 Index]