how draw line between two classes.

Ahmed Mostfa

2016 3 21

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5 次查看（30 天）

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Lecture8.pdf

I have Linear classification, but I don't know how to draw the projected line into my data. The line should look like the picture in page 21 from attached pdf, but instead it is been projected in opposite. The problem is in quiver. Is there a way to project the line as the documentation? Thank you in advance.

x1=[1 2;2 3;3 3;4 5;5 5]'  % the first class 5 observations
x2=[1 0;2 1;3 1;3 2;5 3]' % the second class 6 observations
m1 = mean(x1')'; 
m2 = mean(x2')'; 
m = m1 + m2; 
  Sw1 = zeros(size(x1, 1), size(x1,1)); 
  Sw2 = zeros(size(x1, 1), size(x1,1)); 
 for i = 1:size(x1,1)
     Sw1 =  Sw1 + (x1(:,i)-m1)*(x1(:,i)-m1)';
 end
  for i = 1:size(x2,1)
     Sw2 =  Sw2 + (x2(:,i)-m2)*(x2(:,i)-m2)';
  end
   Sw = Sw1 + Sw2; 
   w = Sw^(-1)*(m2-m1);
   scatter(x1(1,:), x1(2,:), 10, 'ro');
   hold on;
   scatter(x2(1,:), x2(2,:), 10,'bo');
   c = 0.5.*m; 
   quiver(c(1,1), c(2,1), 1, -w(1,1)/w(2,1));
   quiver(c(1,1), c(2,1), -1, w(1,1)/w(2,1));
   quiver(w(1,1),w(2,1), 0.5);
  figure; 
  y1 = x1'*w; 
  y2 = x2'*w; 
hist([y1 y2])