Ridge Path Value

Problem

Evaluate the 1D ridge regression solution along the regularization path.

Return sum(xi * yi) / (sum(xi ** 2) + lam). An empty input returns 0.0. Larger lam shrinks the coefficient toward zero.

Hint

Ridge adds lam to the Gram diagonal, which for one feature is sum(xi ** 2).

case 1

in: [[1,2,3],[2,4,6],0]

expected: 2

case 2

in: [[1,2,3],[2,4,6],5]

expected: 1.4736842105263157

case 3

in: [[1,1],[1,-1],2]

expected: 0

case 4

in: [[],[],1]

expected: 0

Starter codePython

def ridge_path_value(X, y, lam):
    # Your code here
    pass

4 test cases · run your code against them in the editor