% 
% Written by:
% -- 
% John L. Weatherwax                2007-07-01
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

close all; clc; clear; 

mu1 = [ 0.1, 0.1 ].';
mu2 = [ 2.1, 1.9 ].';
mu3 = [ -1.5, 2.0 ].';

S = [ [ 1.2, 0.4 ]; [ 0.4, 1.8 ] ];
w1 = S \ mu1;
w2 = S \ mu2;
w3 = S \ mu3;

P = 1/3;
w10 = log(1/3) - 0.5 * (mu1.') * w1;
w20 = log(1/3) - 0.5 * (mu2.') * w2;
w30 = log(1/3) - 0.5 * (mu3.') * w3;

x = [ 2.1; 1.9 ];

% Compute the three discriminant values:
%
g1 = (w1.')*x + w10;
g2 = (w2.')*x + w20;
g3 = (w3.')*x + w30;

[m, class] = max( [g1, g2, g3] );