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RXshrink (version 2.3)

RXshrink-internal: Internal RXshrink functions

Description

These are internal functions for printing and calculating quantities such as additive K-factors and multiplicative Delta-Factors that determine a specified m-Extent of Shrinkage. mstep() is called by qm.ridge(), true.risk(), true.simu(), aug.lars() and uc.lars(). kofm1(), mofk1() and mapp() are called by YonX(). B19() is called by plot.eff.ridge() and plot.qm.ridge().

Usage

mstep(mobj, kinc, p, qp, eqm1)
  mofk1(k, dMSE)
  kofm1(muobj, dMSE, delmax)
  mapp(mVal, YXobj)
  B19(x)

Value

An output list consisting of two objects (k-factor & d-matrix):

kinc

New k-factor producing an m-Extent-of-shrinkage of mobj.

d

A pxp diagonal matrix of multiplicative shrinkage delta-factors for the uncorrelated components of the regression coefficient vector. p = 1 in mofk1().

m

m-Extent of Shrinkage output by mofk1() or mapp().

kStar

New k-factor producing an m-Extent-of-shrinkage of muobj.

Arguments

mobj

Objective value for the M-extent-of-shrinkage along a path of shape qp.

kinc

Previous additive eigenvalue inflation constant yielding a smaller mobj.

p

Number of estimates in the regression coefficient vector.

qp

Shrinkage path Q-shape parameter.

eqm1

Vector of X'X eigenvalues raised to the power (qp-1).

k

Multiplicative factor that must decrease to increase shrinkage.

dMSE

MSE Optimal Shrinkage delta-factor for YonX().

muobj

Objective value for M-extent-of-shrinkage in kofm1().

delmax

Scalar value strictly < 1. Default value is delmax = 0.999999.

mVal

Objective M-extent-of-shrinkage in mapp().

YXobj

YonX object used by mapp().

x

Numerical value argument for B19().

Author

Bob Obenchain <wizbob@att.net>