How do I plot the W vector used in LDA?

PK Douglas

2015 5 8

0 个回答

6 次查看（30 天）

0 个投票

Hi, I would like to plot some data, run LDA, and plot not only the discriminant , but also the W vector (orthogonal to the discriminator). I am interested in looking at the strength of the w vector when projected onto each axis.

I've tried the code below, which plots the discriminant, but I'm not sure how to access the W vector:

    % 
n=80; %number of data points in each class
info=ones(n,2); info(:,1)=2.4; info(:,2)=1.2;
X = [randn(n,2)+1; randn(n,2) + info];
Y = [ zeros(n,1); ones(n,1)];
gscatter(X(:,1),X(:,2),Y,['k','r'],'..',[16 16]);
% run lda -------------------------
C = ClassificationDiscriminant.fit(X,Y);
Class1 = 1; Class2 = 2;
K = C.Coeffs(Class1,Class2).Const;
L = C.Coeffs(Class1,Class2).Linear;
f = @(x,y) K + [x y]*L;
hold on;
ezplot(f, [min(X(:,1)) max(X(:,1)) min(X(:,2)) max(X(:,2))]);