Coverage for gamdpy/interactions/potential_functions/make_IPL_n.py: 100%

1import numpy as np 

2import numba 

3import math 

4from numba import cuda 

5 

6def make_IPL_n(n: float, first_parameter:int = 0) -> callable: 

7 """ Inverse Power Law Potential 

8 

9 .. math:: 

10 

11 u(r) = A_n r^{-n} 

12 

13 Parameters 

14 ---------- 

15 

16 n : float 

17 Exponent in the potential 

18 first_parameter : int 

19 The index of the first parameter in the list of parameters. See usage in :func:`gamdpy.add_potential_functions`. 

20 

21 Returns 

22 ------- 

23 

24 potential_function : callable 

25 A function that calculates the IPL potential, 

26 u, s, umm = potential_function(dist, params). 

27 where params = [A_n] 

28 """ 

29 

30 def IPL_n(dist, params): # pragma: no cover 

31 # U(r) = An*r**-n 

32 # Um(r) = n*An*r**-(n+1) 

33 # s = -Um/r = n*An*r**-(n+2), Fx = s*dx 

34 An = params[first_parameter] 

35 invDist = numba.float32(1.0) / dist 

36 

37 u = An * invDist ** n 

38 s = numba.float32(n) * An * invDist ** (n + 2) 

39 umm = numba.float32(n * (n + 1)) * An * invDist ** (n + 2) 

40 return u, s, umm # U(r), s == -U'(r)/r, U''(r) 

41 

42 return IPL_n 

43