# dudi: Duality Diagram

## Description

as.dudi is called by many functions (dudi.pca, dudi.coa, dudi.acm, ...) and not directly by the user. It creates duality diagrams.

t.dudi returns an object of class 'dudi' where the rows are the columns and the columns are the rows of the initial dudi.

is.dudi returns TRUE if the object is of class dudi

redo.dudi computes again an analysis, eventually changing the number of kept axes. Used by other functions.

## Usage

as.dudi(df, col.w, row.w, scannf, nf, call, type, tol = 1e-07,
full = FALSE)
# S3 method for dudi
print(x, …)
is.dudi(x)
redo.dudi(dudi, newnf = 2)
# S3 method for dudi
t(x)
# S3 method for dudi
summary(object, …)
# S3 method for dudi
[(x,i,j)

## Arguments

df

a data frame with n rows and p columns

col.w

a numeric vector containing the row weights

row.w

a numeric vector containing the column weights

scannf

a logical value indicating whether the eigenvalues bar plot should be displayed

nf

if scannf FALSE, an integer indicating the number of kept axes

call

generally match.call()

type

a string of characters : the returned list will be of class c(type, "dudi")

tol

a tolerance threshold for null eigenvalues (a value less than tol times the first one is considered as null)

full

a logical value indicating whether all non null eigenvalues should be kept

x, dudi, object

objects of class dudi

further arguments passed to or from other methods

newnf

an integer indicating the number of kept axes

i,j

elements to extract (integer or empty): index of rows (i) and columns (j)

## Value

as.dudi and all the functions that use it return a list with the following components :

tab

a data frame with n rows and p columns

cw

column weights, a vector with n components

lw

row (lines) weights, a vector with p components

eig

eigenvalues, a vector with min(n,p) components

nf

integer, number of kept axes

c1

principal axes, data frame with p rows and nf columns

l1

principal components, data frame with n rows and nf columns

co

column coordinates, data frame with p rows and nf columns

li

row coordinates, data frame with n rows and nf columns

call

original call

## References

Escoufier, Y. (1987) The duality diagram : a means of better practical applications In Development in numerical ecology, Legendre, P. & Legendre, L. (Eds.) NATO advanced Institute, Serie G. Springer Verlag, Berlin, 139--156.

## Examples

Run this code
# NOT RUN {
data(deug)
dd1 <- dudi.pca(deug\$tab, scannf = FALSE)
dd1
t(dd1)
is.dudi(dd1)
redo.dudi(dd1,3)
summary(dd1)
# }

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