Exercise5 - Week6 Finished

Author: ProgrammerYuan

machine-learning-ex5/ex5/learningCurve.m

@@ -53,7 +53,13 @@
 
 % ---------------------- Sample Solution ----------------------
 
-
+for last = 1:m
+    X_train = X(1:last,:);
+    y_train = y(1:last);
+    theta = trainLinearReg(X_train, y_train, lambda);
+    [error_train(last),] = linearRegCostFunction(X_train, y_train, theta, 0);
+    [error_val(last),] = linearRegCostFunction(Xval, yval, theta, 0);
+end
 
 
 

machine-learning-ex5/ex5/linearRegCostFunction.m

@@ -7,7 +7,8 @@
 
 % Initialize some useful values
 m = length(y); % number of training examples
-
+theta_temp = theta;
+theta_temp(1) = 0;
 % You need to return the following variables correctly 
 J = 0;
 grad = zeros(size(theta));
@@ -18,16 +19,9 @@
 %
 %               You should set J to the cost and grad to the gradient.
 %
-
-
-
-
-
-
-
-
-
-
+h = X * theta;
+J = sum((h - y).^2) / (2 * m) + lambda * sum(theta_temp.^2) / (2 * m);
+grad = (X' * (h - y)) / m + lambda * theta_temp / m;
 
 
 % =========================================================================

machine-learning-ex5/ex5/polyFeatures.m

@@ -15,7 +15,9 @@
 %
 % 
 
-
+for i = 1:p
+    X_poly(:,i) = X.^i;
+end
 
 
 

machine-learning-ex5/ex5/validationCurve.m

@@ -11,10 +11,11 @@
 
 % Selected values of lambda (you should not change this)
 lambda_vec = [0 0.001 0.003 0.01 0.03 0.1 0.3 1 3 10]';
-
+% Calculate the length of the lambda_vec
+n_lambda = length(lambda_vec);
 % You need to return these variables correctly.
-error_train = zeros(length(lambda_vec), 1);
-error_val = zeros(length(lambda_vec), 1);
+error_train = zeros(n_lambda, 1);
+error_val = zeros(n_lambda, 1);
 
 % ====================== YOUR CODE HERE ======================
 % Instructions: Fill in this function to return training errors in 
@@ -39,8 +40,12 @@
 %
 %
 
-
-
+for i = 1:n_lambda
+    lambda = lambda_vec(i);
+    theta = trainLinearReg(X, y, lambda);
+    [error_train(i),] = linearRegCostFunction(X, y, theta, 0);
+    [error_val(i),] = linearRegCostFunction(Xval, yval, theta, 0);
+end