Coverage for src/susi/utils/polynomials.py: 16%

1from typing import Optional 

2 

3EPS = 1e-5 

4 

5 

6def __locally_extreme_values(poly, interval: tuple = (None, None)) -> tuple: 

7 points = [] 

8 if interval[0] is not None: 

9 points.append(interval[0]) 

10 for x in poly.deriv().roots: 

11 if interval[0] is not None and x < interval[0]: 

12 continue 

13 if interval[1] is not None and x > interval[1]: 

14 continue 

15 points.append(x) 

16 if interval[1] is not None: 

17 points.append(interval[1]) 

18 points.sort() 

19 values = [poly(x) for x in points] 

20 return points, values 

21 

22 

23def min_value(poly, interval: tuple = (None, None)) -> Optional[float]: 

24 """ 

25 Return the minimum value of the polynomial within the given range 

26 (or globally, if no range is given) 

27 """ 

28 xes, yes = __locally_extreme_values(poly, interval) 

29 if len(yes) > 1: 

30 return min(yes) 

31 if poly(xes[0] - EPS) > yes[0] and poly(xes[0] + EPS) > yes[0]: 

32 return yes[0] 

33 return None 

34 

35 

36def max_value(poly, interval: tuple = (None, None)) -> Optional[float]: 

37 """ 

38 Return the maximum value of the polynomial within the given range 

39 (or globally, if no range is given) 

40 """ 

41 xes, yes = __locally_extreme_values(poly, interval) 

42 if len(yes) > 1: 

43 return max(yes) 

44 if poly(xes[0] - EPS) < yes[0] and poly(xes[0] + EPS) < yes[0]: 

45 return yes[0] 

46 return None