Implementing cost function for collaborative filtering

tjaskula · tjaskula · commit 19b0740c8705 · 2015-11-18T00:15:16.000+01:00
diff --git a/Machine Learning/Week 9/machine-learning-ex8/ex8/cofiCostFunc.m b/Machine Learning/Week 9/machine-learning-ex8/ex8/cofiCostFunc.m
@@ -41,7 +41,13 @@
 %
 
 
+errors = (X*Theta' - Y) .* R;
+regularizationTheta = lambda/2 * sum(sum(Theta.^2));
+regularizationX = lambda/2 * sum(sum(X.^2));
 
+J = 1/2 * sum(sum(errors .^2)) + regularizationTheta + regularizationX;
+X_grad = errors * Theta + lambda * X;
+Theta_grad = errors' * X + lambda * Theta;
 
 % =============================================================
 

Original file line number	Diff line number	Diff line change
`@@ -41,7 +41,13 @@`
`41`	`41`	`%`
`42`	`42`
`43`	`43`
	`44`	`+errors = (XTheta' - Y) . R;`
	`45`	`+regularizationTheta = lambda/2 * sum(sum(Theta.^2));`
	`46`	`+regularizationX = lambda/2 * sum(sum(X.^2));`
`44`	`47`
	`48`	`+J = 1/2 * sum(sum(errors .^2)) + regularizationTheta + regularizationX;`
	`49`	`+X_grad = errors * Theta + lambda * X;`
	`50`	`+Theta_grad = errors' * X + lambda * Theta;`
`45`	`51`
`46`	`52`	`% =============================================================`
`47`	`53`