targetF: Computation of target F ('constant correlation model').

Description Usage Arguments Value Author(s) References See Also Examples

View source: R/targetF.R

Description

The p x p target F is computed from the n x p data matrix. It is defined as follows (i,j = 1,...,p):

tij = sii if i=j ; r√{s_{ii}s_{jj}} otherwise

where r is the average of sample correlations and sij denotes the entry of the unbiased covariance matrix in row i, column j.

Usage

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targetF(x, genegroups)

Arguments

x

A n x p data matrix.

genegroups

The genegroups are not used for this target.

Value

A p x p matrix.

Author(s)

Monika Jelizarow and Vincent Guillemot

References

J. Schaefer and K. Strimmer, 2005. A shrinkage approach to large-scale covariance matrix estimation and implications for functional genomics. Statist. Appl. Genet. Mol. Biol. 4:32.

See Also

targetCor, targetF, targetG, targetGstar, targetGpos.

Examples

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# A short example on a toy dataset
# require(SHIP)
data(expl)
attach(expl)
tar <- targetF(x,NULL)
which(tar[upper.tri(tar)]!=0) # many non zero coefficients !

SHIP documentation built on May 29, 2017, 11:25 a.m.