Least Squares Residual Sum of Squares

Problem

Compute the residual sum of squares for a candidate solution x of A*x = b:

RSS = ||A*x - b||^2

Return the scalar sum of squared residuals. A zero result means x solves the system exactly.

Hint

Form the residual vector first, then square and sum its entries.

case 1

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

expected: 0

case 2

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

expected: 0

case 3

in: [[[1],[1]],[1,3],[1]]

expected: 4

case 4

in: [[[1,0],[0,1]],[1,1],[2,2]]

expected: 2

case 5

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

expected: 0

Starter codePython

def least_squares_rss(A, b, x):
    # Your code here
    pass

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