question 1

marc0uk · Nov 6, 2011 · 5b92130 · 5b92130
1 parent 15329dc
commit 5b92130
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diff --git a/mlclass-ex3/mlclass-ex3/lrCostFunction.m b/mlclass-ex3/mlclass-ex3/lrCostFunction.m
@@ -37,16 +37,20 @@
 %
 
 
+% calculate hypothesis
+h = sigmoid(X*theta);
 
+% regularize theta by removing first value
+theta_reg = [0;theta(2:end, :);];
 
+J = (1/m)*(-y'* log(h) - (1 - y)'*log(1-h))+(lambda/(2*m))*theta_reg'*theta_reg;
 
+grad = (1/m)*(X'*(h-y)+lambda*theta_reg);
 
 
 
 
 
 % =============================================================
 
-grad = grad(:);
-
 end
diff --git a/octave_cheat_sheet.txt b/octave_cheat_sheet.txt
@@ -270,4 +270,6 @@ initialTheta = zeros(n,1); % can we do better?
 
 % INIT_EPSILON is unrelated to EPSILON
 Theta1 = rand(10,11) * (2*INIT_EPSILON) - INIT_EPSILON;
-Theta1 = rand(1,11) * (2*INIT_EPSILON) - INIT_EPSILON;
+Theta1 = rand(1,11) * (2*INIT_EPSILON) - INIT_EPSILON;
+
+load('ex3data1.mat');