R: Reconstitution of Data from a Duality Diagram

reconst {ade4} | R Documentation

## Reconstitution of Data from a Duality Diagram

### Description

Generic Function for the reconstitution of data from a principal component analysis or a correspondence analysis

### Usage

    reconst (dudi, ...)
    ## S3 method for class 'pca'
    reconst(dudi, nf = 1, ...)
    ## S3 method for class 'coa'
    reconst(dudi, nf = 1, ...)

### Arguments

`dudi` | an object of class `dudi` used to select a method: pca or coa
`nf` | an integer indicating the number of kept axes for the reconstitution
`...` | further arguments passed to or from other methods

### Value

returns a data frame containing the reconstituted data

### Author(s)

Daniel Chessel
Anne-Béatrice Dufour anne-beatrice.dufour@univ-lyon1.fr

### References

Gabriel, K.R. (1978) Least-squares approximation of matrices by additive and multiplicative models. Journal of the Royal Statistical Society, B , 40, 186–196.

### Examples

    data(rhone)
    dd1 <- dudi.pca(rhone$tab, nf = 2, scann = FALSE)
    rh1 <- reconst(dd1, 1)
    rh2 <- reconst(dd1, 2)
    par(mfrow = c(4,4))
    par(mar = c(2.6,2.6,1.1,1.1))
    for (i in 1:15) {
        plot(rhone$date, rhone$tab[,i])
        lines(rhone$date, rh1[,i], lty = 2)
        lines(rhone$date, rh2[,i], lty = 1)
        ade4:::scatterutil.sub(names(rhone$tab)[i], 2, "topright")}

    data(chats)
    chatsw <- data.frame(t(chats))
    chatscoa <- dudi.coa(chatsw, scann = FALSE)
    model0 <- reconst(chatscoa, 0)
    round(model0,3)
    round(chisq.test(chatsw)$expected,3)
    chisq.test(chatsw)$statistic
    sum(((chatsw-model0)^2)/model0)
    effectif <- sum(chatsw)
    sum(chatscoa$eig)*effectif
    model1 <- reconst(chatscoa, 1)
    round(model1, 3)
    sum(((chatsw-model1)^2)/model0)
    sum(chatscoa$eig[-1])*effectif

[Package ade4 version 1.7-17 Index]