import numpy as np
from numba import jit
from gtsimulation.GT import GTSimulator
from gtsimulation.Global import Constants
[docs]
class BunemanBorisSimulator(GTSimulator):
[docs]
def AlgoStep(self, T, M, q, V, X, H, E):
c = Constants.c
if M != 0:
return self.__algo(E, H, M, T, V, q, c)
else:
return V, 0, 0
@staticmethod
@jit(fastmath=True, nopython=True)
def __algo(E, H, M, T_particle, V, q, c):
H_norm = np.linalg.norm(H)
Yp = T_particle / M + 1
if H_norm == 0 and np.linalg.norm(E) == 0:
return V, Yp, Yp
Ui = Yp * V
TT = Yp * np.tan(q * H_norm / Yp)
T = TT * H / H_norm if H_norm > 0 else np.zeros(3)
U = np.cross(V, T) + 2 * q * E + Ui
UU = (np.dot(U, T)) ** 2 / c ** 2
YY = np.sqrt(1 + np.linalg.norm(U) ** 2 / c ** 2)
S = YY ** 2 - TT ** 2
Ym = Yp
Yp = np.sqrt(0.5 * (S + np.sqrt(S ** 2 + 4 * (TT ** 2 + UU))))
Ya = 0.5 * (Ym + Yp)
tt = np.tan(q * H_norm / Yp)
t = tt * H / H_norm if H_norm > 0 else np.zeros(3)
s = 1 / (1 + tt ** 2)
Vp = s / Yp * (U + t * np.dot(U, t) + np.cross(U, t))
return Vp, Yp, Ya