Euler Stability Condition

Problem

Forward Euler applied to y' = lam*y multiplies the value by the amplification factor 1 + h*lam at every step.

The method is stable when |1 + h*lam| <= 1. Given lam and the step size h, return [factor, stable] where stable is a boolean.

Hint

For negative lam the stability limit is h <= 2 / |lam|.

case 1

in: [-10,0.1]

expected: [0,true]

case 2

in: [-10,0.25]

expected: [-1.5,false]

case 3

in: [0,5]

expected: [1,true]

case 4

in: [-2,1]

expected: [-1,true]

Starter codePython

def euler_stability(lam, h):
    # Return [factor, stable]
    # Your code here
    pass

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