def test_backwards_time(self):
sim = rebound.Simulation(binary)
sim.integrator = "ias15"
rebx = reboundx.Extras(sim)
times = [0, 2000., 4000., 6000., 8000., 10000.]
values = [1., 0.8, 0.6, 0.4, 0.3, 0.2]
starmass = reboundx.Interpolator(rebx, times, values, "spline")
Nout = 1000
ts = np.linspace(0., 1.e4, Nout)
ps = sim.particles
a10 = ps[1].a
m0 = ps[0].m
for i, time in enumerate(ts):
sim.integrate(time)
ps[0].m = starmass.interpolate(rebx, t=sim.t)
sim.move_to_com(
) # lost mass had momentum, so need to move back to COM frame
sim.dt = -0.001
for i, time in enumerate(times[::-1]):
sim.integrate(time)
ps[0].m = starmass.interpolate(rebx, t=sim.t)
sim.move_to_com(
) # lost mass had momentum, so need to move back to COM frame
self.assertLess(abs((ps[0].m - m0) / m0), 1.e-2)
self.assertLess(abs((ps[1].a - a10) / a10), 1.e-2)
def test_klo(self):
sim = rebound.Simulation(binary)
sim.integrator = "ias15"
rebx = reboundx.Extras(sim)
times = [0, 2000., 4000., 6000., 8000., 10000.]
values = [1., 0.8, 0.6, 0.4, 0.3, 0.2]
starmass = reboundx.Interpolator(rebx, times, values, "spline")
m0 = sim.particles[0].m
mint0 = starmass.interpolate(rebx, t=0)
self.assertLess(abs((m0 - mint0) / m0), 1.e-6)
mint1 = starmass.interpolate(rebx, t=5000) # advance klo
mint1 = starmass.interpolate(rebx, t=0) # advance klo
self.assertLess(abs((m0 - mint1) / m0), 1.e-6)
for i, w in enumerate(watts):
lumins[i] = (w * ((6.7e-12)**2) * (5e-31)) / ((3.2e-8)**3)
t_fs = np.zeros(lumins.size) # precalculate t_f (Eq. 1)
for i, l in enumerate(lumins):
t_fs[i] = np.cbrt(masses[i] * radii[i]**2 / l)
taus = np.zeros(t_fs.size) # precalc tau (Eq. 2)
G = 4 * np.pi**2 # units of AU, yr, and Msun
for i, t_f in enumerate(t_fs):
taus[i] = 2. * radii[i]**3 / G / masses[i] / t_f
# main loop
for i, interval in enumerate(intervals):
# initialize sim and create Interpolator objects
timer_start = time.perf_counter()
sim, rebx, tides = makesim()
starmass = reboundx.Interpolator(rebx, mtimes, masses, 'spline')
starradius = reboundx.Interpolator(rebx, rtimes, radii, 'spline')
startau = reboundx.Interpolator(rebx, ltimes, taus, 'spline')
# update Sun's mass and radius accordingly
ps = sim.particles
ps[0].m = starmass.interpolate(rebx, t=T0)
ps[0].r = starradius.interpolate(rebx, t=T0)
ps[0].params["tctl_k1"] = 0.038 # ~ lambda_2, Schroder & Smith (2008)
ps[0].params["tctl_tau"] = startau.interpolate(rebx, t=T0)
ps[0].params["Omega"] = 0 # explicitly set to 0 (would be 0 by default)
# initialize main sim
tmax = 5e6 # max sim integration time
Nup = int(tmax / interval) # no. of param updates
ts = np.linspace(0., tmax, Nup)
