Extremum of a homogeneous quadratic function

QuadraticExtremum.py

# [9/20/2012] Challenge #100 [difficult] (Min-Max of N-Dimensional Quadratic) : dailyprogrammer http://www.reddit.com/r/dailyprogrammer/comments/106hps/9202012_challenge_100_difficult_minmax_of/ 

import numpy as np
import copy as copy

# quadratic form input
original = [[2, -2, -1], [-2, 1, 0], [-1, 0, 3]]
q = copy.deepcopy(original)

d = len(q) - 1

# take partial derivatives. Off-diag elements do not change.
for i in range(0, d):
    q[i][i] = 2 * q[i][i] # multiply diagonal elements by 2

# form the coefficient and auxillary matrices
C = np.delete(q, d, 0)
C = np.delete(C, d, 1)
A = q[d]
A.remove(A[d])
for i in range(0, len(A) - 1):
    A[i] = -A[i]

# solve the system
zero = np.zeros(d)
s = np.linalg.solve(C, A)
s

if np.array_equal(s, zero): 
    print("No extremum exists.")
else:
    print("An extremum occurs at " + str(s))