CA: Correspondence analysis

In easyCODA: Compositional Data Analysis in Practice

Correspondence analysis

Description

Computation of correspondence analysis on a table of nonnegative data.

Usage

CA(data, nd = 2, suprow = NA, supcol = NA)

Arguments

data	A data frame or matrix of nonnegative data (no negative values)
nd	Number of dimensions for summary solution if not 2 (default)
suprow	Indices of rows that are supplementary points
supcol	Indices of columns that are supplementary points

Details

The function CA is a simple wrapper for the ca function in the ca package (Nenadic and Greenacre, 2007), for compatibility within the easyCODA package.

Supplementary rows and columns can be declared (also known as passive points) – these do not contribute to the solution but are positioned on the solution axes.

The function borrows the structure and functions of the ca package, which is required, and produces a ca object, and the same print, summary and plot methods can be used, as for a ca object. It additionally exports the principal coordinates of both the rows and columns, not presently found in the ca package.

Value

sv	Singular values
nd	Number of dimensions in solution results
rownames	Row names
rowmass	Row weights
rowdist	Row logratio distances to centroid
rowinertia	Row inertias
rowcoord	Row standard coordinates
rowpcoord	Row principal coordinates
rowsup	Indices of row supplementary points
colnames	Column names
colmass	Column weights
coldist	Column logratio distances to centroid
colinertia	Column inertias
colcoord	Column standard coordinates
colpcoord	Column principal coordinates
N	The compositional data table

Author(s)

Michael Greenacre

References

Nenadic, O. and Greenacre, M. (2007). Correspondence analysis in R, with two- and three-dimensional graphics: The ca package. Journal of Statistical Software, 20 (3), https://www.jstatsoft.org/v20/i03/

See Also

PLOT.CA, plot.ca, summary.ca, print.ca

Examples

# CA of the Roman cups data (symmetric map)
data("cups")
PLOT.CA(CA(cups))

easyCODA documentation built on Sept. 11, 2024, 5:33 p.m.