From b444304a89c6c55727aeaa7f6794829f894caea4 Mon Sep 17 00:00:00 2001
From: Michael Zhang <mail@mzhang.io>
Date: Wed, 15 Nov 2023 22:35:25 -0600
Subject: [PATCH] wtf

---
 assignments/hwk03/EMG.m    | 16 ++++++++--------
 assignments/hwk03/M_step.m | 11 +++++++++--
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/assignments/hwk03/EMG.m b/assignments/hwk03/EMG.m
index c4fe80c..93a1749 100644
--- a/assignments/hwk03/EMG.m
+++ b/assignments/hwk03/EMG.m
@@ -22,12 +22,12 @@ function [h, m, Q] = EMG(x, k, epochs, flag)
   Q = zeros(epochs*2,1); % vector that can hold complete data log-likelihood after each E and M step
 
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  % TODO: Initialise cluster means using k-means
+  % Initialise cluster means using k-means
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   [~, ~, ~, D] = kmeans(x, k);
  
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  % TODO: Determine the b values for all data points
+  % Determine the b values for all data points
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   for i = 1:num_data
     row = D(i,:);
@@ -36,7 +36,7 @@ function [h, m, Q] = EMG(x, k, epochs, flag)
   end
   
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  % TODO: Initialize pi's (mixing coefficients)
+  % Initialize pi's (mixing coefficients)
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   pi = zeros(k, 1);
   for i = 1:k
@@ -44,8 +44,8 @@ function [h, m, Q] = EMG(x, k, epochs, flag)
   end
 
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  % TODO: Initialize the covariance matrix estimate
-  %       further modifications will need to be made when doing 2(d)
+  % Initialize the covariance matrix estimate
+  % further modifications will need to be made when doing 2(d)
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   m = zeros(k, dim);
   for i = 1:k
@@ -63,13 +63,13 @@ function [h, m, Q] = EMG(x, k, epochs, flag)
     [h] = E_step(x, h, pi, m, S, k);
     
     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-    % TODO: Store the value of the complete log-likelihood function
+    % Store the value of the complete log-likelihood function
     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     L = 0;
     for i = 1:num_data
       for j = 1:k
         prior = mvnpdf(x, m(j, :), S(:, :, j));
-        L = L + h(i, j) * (log(pi(i)) + log(prior(i)));
+        L = L + h(i, j) * (log(pi(j)) + log(prior(j)));
       end
     end
 
@@ -77,7 +77,7 @@ function [h, m, Q] = EMG(x, k, epochs, flag)
     % M-step
     %%%%%%%%%%%%%%%%
     fprintf('M-step, epoch #%d\n', n);
-    [Q, S, m] = M_step(x, Q, h, S, k);
+    [Q, S, m] = M_step(x, h, S, k, flag);
     
     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     % TODO: Store the value of the complete log-likelihood function
diff --git a/assignments/hwk03/M_step.m b/assignments/hwk03/M_step.m
index 97105e8..e205eec 100644
--- a/assignments/hwk03/M_step.m
+++ b/assignments/hwk03/M_step.m
@@ -18,9 +18,16 @@ function [S, m, pi] = M_step(x, h, S, k, flag)
   lambda = 1e-3; % value for improved version of EM
 
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  % TODO: update mixing coefficients
+  % update mixing coefficients
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  
+  pi = zeros(k, 1);
+  for i = 1:num_data
+    row = h(i, :);
+    maxValue = max(row);
+    maxIdx = find(row == maxValue);
+    pi(maxIdx) = pi(maxIdx) + 1;
+  end
+  pi = pi ./ num_data;
   
 
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%