/exercises/mlclass-ex1/computeCost.m

 1function J = computeCost(X, y, theta)
 2%COMPUTECOST Compute cost for linear regression
 3%   J = COMPUTECOST(X, y, theta) computes the cost of using theta as the
 4%   parameter for linear regression to fit the data points in X and y
 5
 6% Initialize some useful values
 7m = length(y); % number of training examples
 8
 9% You need to return the following variables correctly 
10J = 0;
11
12% ====================== YOUR CODE HERE ======================
13% Instructions: Compute the cost of a particular choice of theta
14%               You should set J to the cost.
15
16J = sum(((X*theta)-y).^2)/(2*m);
17% =========================================================================
18
19end