[R] plot discriminant analysis

Alejo C.S. alej.c.s at gmail.com
Wed Oct 14 14:20:07 CEST 2009


I'm confused on how is the right way to plot a discriminant analysis made by
lda function (MASS package).
(I had attached my data fro reproduction). When I plot a lda object :

X <- read.table("data", header=T)

lda_analysis <- lda(formula(X), data=X)

plot(lda_analysis)

#the above plot is completely different to:

plot(predict(lda_analysis)$x, col=palette()[predict(lda_analysis)$class])

that should be the same graph than the first?

In the second case, I use predict function to obtain the LD1 and LD2
coordinates of lda_analysis (predict(lda_analysis)$x) and it's respective
class (predict(lda_analysis)$class), but it seems that the classes are
different:

table(X$G3, predict(lda_analysis)$class)

        B    G   M
  B  29    0    3
  G    0  26   2
  M   4    0  46


any clues?
Regards,


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