RXshrink (version 1.4.3)

kofm: k-Multipliers and delta-Factors for unr.ridge() Shrinkage.

Description

The kofm() function computes the "kStar" multipliers and the diagonal "d" Matrices used by the unr.ridge() function. While these calculations are extensive, they are greatly simplified by using interpolation between "knots" on "piecewise linear-spline" functions.

Usage

kofm(muobj, p, dMSE, delmax = 0.999999)

Arguments

muobj

A "numeric" value that is >= 0 and <= p.

p

The integer number of non-constant x-variables used in defining the linear model being fitted to ill-conditioned (intercorrelated, confounded) data. Note that p must also be rank of the given X-matrix.

dMSE

Maximum Likelihood estimates of minimum MSE risk Shrinkage Delta-Factors.

delmax

Maximum allowed value for Shrinkage delta-factors that is strictly less than 1. (default = 0.999999, which prints as 1 when rounded to fewer than 6 decimal places.)

Value

An output list of two objects:

kStar

The k-factor needed to multiply each given dMSE-factor.

d

The (p x p) diagonal matrix of requested shrinkage-factors.

References

Obenchain RL. (2020) Ridge TRACE Diagnostics. https://arxiv.org/abs/2005.14291

Obenchain RL. (2020) The Unrestricted Shrinkage Path: Technical Details. "unrPath.pdf" http://localcontrolstatistics.org

See Also

unr.ridge and mofk.