def integrate_solar_system(sun, planets, time_end=5.0 | units.yr, n_steps=500):
"""
evolve the system using kepler_orbiters
"""
converter = nbody_system.nbody_to_si(1 | units.MSun, 1 | units.AU)
planets_around_sun = Kepler(converter, channel_type="sockets")
# central particle
planets_around_sun.central_particle.add_particles(sun[0:1])
# to set the central particle at the center of the coordinate system
#planets_around_sun.central_particle.position = (0.0, 0.0, 0.0) | units.AU
#planets_around_sun.central_particle.velocity = (0.0, 0.0, 0.0) | units.kms
# orbiters
planets_around_sun.orbiters.add_particles(planets)
planets_around_sun.commit_particles()
# to change the integration method
#planets_around_sun.parameters.method = 1
#print planets_around_sun.get_method()
channel_from_planetets_to_framework = planets_around_sun.orbiters.new_channel_to(
planets)
channel_from_sun_to_framework = planets_around_sun.central_particle.new_channel_to(
sun)
positions_sun = quantities.AdaptingVectorQuantity()
positions_planets = quantities.AdaptingVectorQuantity()
dt = time_end / float(n_steps)
time = 0.0 | units.yr
print " ** evolving solar system for", time_end.in_(
units.yr), ", with time-step of", dt.in_(units.yr)
print " this might take a while"
while time <= time_end:
#print "\t", time.in_(units.yr)
planets_around_sun.evolve_model(time)
channel_from_planetets_to_framework.copy()
channel_from_sun_to_framework.copy()
positions_sun.append(sun.position)
positions_planets.append(planets.position)
time += dt
print " **"
planets_around_sun.stop()
return positions_sun, positions_planets
def test1(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun,
149.5e6 | units.km)
instance = Kepler(
convert_nbody) #, redirection="none")#, debugger="xterm")
instance.initialize_code()
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
instance.central_particle.add_particle(stars[0])
earth = instance.orbiters.add_particle(stars[1])
instance.commit_particles()
instance.evolve_model(365 | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
position_at_start = earth.position.value_in(units.AU)[0]
position_after_full_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostEqual(position_at_start, position_after_full_rotation,
6)
instance.evolve_model(365.0 + (365.0 / 2) | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
position_after_half_a_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostEqual(-position_at_start,
position_after_half_a_rotation, 3)
instance.evolve_model(365.0 + (365.0 / 2) + (365.0 / 4) | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
position_after_half_a_rotation = earth.position.value_in(units.AU)[1]
self.assertAlmostEqual(-position_at_start,
position_after_half_a_rotation, 3)
instance.cleanup_code()
instance.stop()
def test1(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = Kepler(convert_nbody)#, redirection="none")#, debugger="xterm")
instance.initialize_code()
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
instance.central_particle.add_particle(stars[0])
earth = instance.orbiters.add_particle(stars[1])
instance.commit_particles()
instance.evolve_model(365 | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
position_at_start = earth.position.value_in(units.AU)[0]
position_after_full_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostEqual(position_at_start, position_after_full_rotation, 6)
instance.evolve_model(365.0 + (365.0 / 2) | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
position_after_half_a_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostEqual(-position_at_start, position_after_half_a_rotation, 3)
instance.evolve_model(365.0 + (365.0 / 2) + (365.0 / 4) | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
position_after_half_a_rotation = earth.position.value_in(units.AU)[1]
self.assertAlmostEqual(-position_at_start, position_after_half_a_rotation, 3)
instance.cleanup_code()
instance.stop()
def test0(self):
instance = Kepler()
instance.stop()
def test0(self):
instance = Kepler()
instance.stop()