sla.prcomp {RScaLAPACK}R Documentation

Principal Components Analysis (Using ScaLAPACK)

Description

The function sla.prcomp performs a principal components analysis on the give data matrix (using sla.svd) and returns the results as a object of class prcomp.

Usage

sla.prcomp(x, retx=TRUE, center=TRUE, scale.=FALSE, tol=NULL, NPROWS, NPCOLS, MB)

Arguments

x

A numeric matrix which provides the data for the principal components analysis.

retx

a logical value indicating whether the rotated variables should be returned.

center

a logical value indicating whether the variables should be shifted to be zero centered. Alternately, a vector of length ncols(x). The value is passed to scale.

scale.

a logical value indicating whether the variables should be scaled to have unit variance before the analysis takes place. The default is FALSE for old compatibility, but in general scaling is advisable. Alternately, a vector of length ncols(x). The value is passed to scale.

tol

a value indicating the magnitude below which components should be omitted. The default is to omit no components.

NPROWS

Number of Process Rows in the Process Grid.

NPCOLS

Number of Process Cols in the Process Grid.

MB

Block Size.

Details

If the number of processor rows and columns are both zero, one processor is used. If the number of processor rows is nonzero and the number of processor columns is zero, then the processor rows is taken to be a number of processors, and a grid is made accordingly.

Value

sdev

the standard deviations of the principal components.

rotation

the matrix of variable loadings (i.e., a matrix whose columns contain the eigenvectors).

x

if retx is true, the value of the rotated data (the original data multiplied by the rotation matrix).

Author(s)

Nagiza Samatova (samatovan@ornl.gov), Guruprasad Kora (koragh@ornl.gov), Srikanth Yoginath (yoginathsb@ornl.gov), David Bauer (bauerda@ornl.gov)

References

http://www.google.com/search?q=principal+components+analysis

http://www.netlib.org/scalapack/

See Also

prcomp for the normal PCA function.

Examples

data(USArrests)
sla.prcomp(USArrests, scale=TRUE, NPROWS=2, NPCOLS=2, MB=2)

[Package RScaLAPACK version 0.6.1 Index]