Coverage for pySDC/tutorial/step_4/PenningTrap_3D_coarse.py: 100%

1import numpy as np 

2 

3from pySDC.implementations.problem_classes.PenningTrap_3D import penningtrap 

4 

5 

6class penningtrap_coarse(penningtrap): 

7 """ 

8 Coarse level problem description class, will only overwrite what is needed 

9 """ 

10 

11 def eval_f(self, part, t): 

12 """ 

13 Routine to compute the E and B fields (named f for consistency with the original PEPC version) 

14 

15 Args: 

16 t: current time (not used here) 

17 part: the particles 

18 Returns: 

19 Fields for the particles (external only) 

20 """ 

21 

22 self.work_counters['rhs']() # count the evaluations, as the fine problem does 

23 Emat = np.diag([1, 1, -2]) 

24 f = self.dtype_f(self.init, val=0.0) 

25 

26 # only compute external forces here: O(N) instead of O(N*N) 

27 f.elec[:] = self.omega_E**2 / (part.q / part.m) * (Emat @ part.pos) 

28 f.magn[:] = self.omega_B * np.array([0, 0, 1])[:, None] 

29 

30 return f