Stiffness Ratio

Problem

Compute the stiffness ratio of a linear ODE system y' = A*y from its real eigenvalues: max(|lambda_i|) / min(|lambda_i|).

Assume no eigenvalue is zero and eigenvalues may be negative (only magnitudes matter). Return the ratio as a float.

Hint

A large ratio means explicit methods are forced to take very small steps.

case 1

in: [[1,100,3]]

expected: 100

case 2

in: [[-200,0.5,4]]

expected: 400

case 3

in: [[5,5]]

expected: 1

case 4

in: [[-1,-2,-4]]

expected: 4

case 5

in: [[0.25]]

expected: 1

Starter codePython

def stiffness_ratio(eigenvalues):
    # Your code here
    pass

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