Coverage for openxps/bounds/reflective.py: 100%

1""" 

2Reflective boundary condition. 

3 

4.. module:: openxps.bounds.reflective 

5 :platform: Linux, MacOS, Windows 

6 :synopsis: Reflective boundary condition 

7 

8.. classauthor:: Charlles Abreu <craabreu@gmail.com> 

9 

10""" 

11 

12from .base import Bounds 

13 

14 

15class ReflectiveBounds(Bounds): 

16 """ 

17 A reflective boundary condition. The dynamical variable collides elastically 

18 with the upper and lower bounds and is reflected back into the range. 

19 

20 Parameters 

21 ---------- 

22 lower 

23 The lower bound for the dynamical variable. 

24 upper 

25 The upper bound for the dynamical variable. 

26 unit 

27 The unity of measurement of the bounds. If the bounds do not have a unit, use 

28 ``dimensionless``. 

29 

30 Example 

31 ------- 

32 >>> import openxps as xps 

33 >>> from openmm import unit 

34 >>> bounds = xps.ReflectiveBounds(1, 10, unit.angstrom) 

35 >>> bounds == xps.ReflectiveBounds(0.1, 1, unit.nanometer) 

36 True 

37 >>> print(bounds) 

38 ReflectiveBounds(lower=1, upper=10, unit=A) 

39 """ 

40 

41 def __post_init__(self) -> None: 

42 super().__post_init__() 

43 self.period = 2 * (self.upper - self.lower) 

44 

45 def leptonExpression(self, variable: str) -> str: 

46 scaled = f"scaled_{variable}" 

47 wrapped = f"wrapped_{variable}" 

48 if self.lower == 0: 

49 shift = deshift = "" 

50 elif self.lower > 0: 

51 shift = f"-{self.lower}" 

52 deshift = f"+{self.lower}" 

53 else: 

54 shift = f"+{-self.lower}" 

55 deshift = f"-{-self.lower}" 

56 return ( 

57 f"min({wrapped},1-{wrapped})*{self.period}{deshift}" 

58 f";\n{wrapped}={scaled}-floor({scaled})" 

59 f";\n{scaled}=({variable}{shift})/{self.period}" 

60 ) 

61 

62 def wrap(self, value: float, rate: float) -> tuple[float, float]: 

63 x = (value - self.lower) % self.period 

64 if x < self.period - x: 

65 return x + self.lower, rate 

66 return self.period - x + self.lower, -rate 

67 

68 

69ReflectiveBounds.registerTag("!openxps.bounds.ReflectiveBounds")