shrinkldaCMA: Shrinkage linear discriminant analysis

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

Description

Linear Discriminant Analysis combined with the James-Stein-Shrinkage approach of Schaefer and Strimmer (2005) for the covariance matrix.

Currently still an experimental version.

For S4 method information, see shrinkldaCMA-methods

Usage

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shrinkldaCMA(X, y, f, learnind, models=FALSE, ...)

Arguments

X

Gene expression data. Can be one of the following:

  • A matrix. Rows correspond to observations, columns to variables.

  • A data.frame, when f is not missing (s. below).

  • An object of class ExpressionSet.

y

Class labels. Can be one of the following:

  • A numeric vector.

  • A factor.

  • A character if X is an ExpressionSet that specifies the phenotype variable.

  • missing, if X is a data.frame and a proper formula f is provided.

WARNING: The class labels will be re-coded to range from 0 to K-1, where K is the total number of different classes in the learning set.

f

A two-sided formula, if X is a data.frame. The left part correspond to class labels, the right to variables.

learnind

An index vector specifying the observations that belong to the learning set. May be missing; in that case, the learning set consists of all observations and predictions are made on the learning set.

models

a logical value indicating whether the model object shall be returned

...

Further arguments to be passed to cov.shrink from the package corpcor

Value

An object of class cloutput.

Note

This is still an experimental version.

Covariance shrinkage is performed by calling functions from the package corpcor.

Variable selection is not necessary.

Author(s)

Martin Slawski ms@cs.uni-sb.de

Anne-Laure Boulesteix boulesteix@ibe.med.uni-muenchen.de

References

Schaefer, J., Strimmer, K. (2005).

A shrinkage approach to large-scale covariance estimation and implications for functional genomics.

Statististical Applications in Genetics and Molecular Biology, 4:32.

See Also

compBoostCMA, dldaCMA, ElasticNetCMA, fdaCMA, flexdaCMA, gbmCMA, knnCMA, ldaCMA, LassoCMA, nnetCMA, pknnCMA, plrCMA, pls_ldaCMA, pls_lrCMA, pls_rfCMA, pnnCMA, qdaCMA, rfCMA, scdaCMA, svmCMA.

Examples

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### load Golub AML/ALL data
data(golub)
### extract class labels
golubY <- golub[,1]
### extract gene expression
golubX <- as.matrix(golub[,-1])
### select learningset
ratio <- 2/3
set.seed(111)
learnind <- sample(length(golubY), size=floor(ratio*length(golubY)))
### run  shrinkage-LDA
result <- shrinkldaCMA(X=golubX, y=golubY, learnind=learnind)
### show results
show(result)
ftable(result)
plot(result)

chbernau/CMA documentation built on May 17, 2019, 12:04 p.m.