[R] Discriminant plot

[Alain Guillet]

Hi Alejo,

According to my knowledge the two plots are different because in the
first one a point belongs to a group depending on its group in the data
whereas in the second plot a point belongs to the group predicted by the
linear discriminant analysis.

I hope somebody will correct me if I am wrong.

Alain


Alejo C.S. wrote:
> Hi Alain, this is the code:
>
>
> library(MASS)
> library(mda)
>
>
> #data attached, first column "G3" group membership
>
> X <- read.table("data", header=T)
>
> lda_analysis <- lda(formula(X), data=X)
>
> plot(lda_analysis, col=palette()[X$G3])
>
> #the above plot is completely different to:
>
> plot(predict(lda_analysis)$x, type="n")
> text(predict(lda_analysis)$x, labels=predict(lda_analysis)$class, 
> col=palette()[predict(lda_analysis)$class])
>
> The above code only reproduce the first plot using predict to obtain 
> coordinates and classes for the first tow discriminant axis.
>
> Thanks ,
>
> Alejo
>

-- 
Alain Guillet
Statistician and Computer Scientist

SMCS - Institut de statistique - Université catholique de Louvain
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