计算代价函数 ????(????)=12????Σ(ℎ????(????(????))−????(????))2

def computeCost(X,y,theta):

    inner = np.power(X*theta.T - y, 2)

    return np.sum(inner,axis=None)/(len(X)*2)

X = np.random.randint(low=10,size=(3,4))

y = np.random.randint(low=10,size=(3,1))

theta = np.random.rand(4,1)

Cost = computeCost(X,y,theta)

print(Cost )