def initialize_huayno(bodies, converter, huayno_eta): stars_gravity = Huayno(converter,channel_type="sockets") stars_gravity.particles.add_particles(bodies) # either bodies or just stars stars_gravity.commit_particles() #stars_gravity.set_timestep_parameter(huayno_eta) stars_gravity.parameters.timestep_parameter = huayno_eta stars_gravity.set_inttype_parameter(12) # CC_KEPLER return stars_gravity
def initialize_huayno(bodies, converter, huayno_eta): stars_gravity = Huayno(converter,channel_type="sockets") stars_gravity.particles.add_particles(bodies) # either bodies or just stars stars_gravity.commit_particles() #stars_gravity.set_timestep_parameter(huayno_eta) stars_gravity.parameters.timestep_parameter = huayno_eta stars_gravity.set_inttype_parameter(12) # CC_KEPLER return stars_gravity
def orbit_evolve(bodies, time_peri, eta, n_steps=100):
converter = nbody_system.nbody_to_si(1 | units.MSun, 1 | units.AU)
gravity = Huayno(converter, channel_type="sockets")
gravity.particles.add_particles(bodies)
gravity.commit_particles()
gravity.parameters.timestep_parameter = eta
channel_from_gravity_to_framework = gravity.particles.new_channel_to(
bodies)
Etot_init = gravity.kinetic_energy + gravity.potential_energy
Etot = Etot_init
file_snap = "orbit_ini.hdf5"
t_end = 2.0 * abs(time_peri.value_in(units.yr)) | units.yr
dt = t_end / float(n_steps)
time = 0.0 | units.yr
while time <= t_end:
gravity.evolve_model(time)
channel_from_gravity_to_framework.copy()
bodies.age = time
# checking energy conservation
Ekin = gravity.kinetic_energy
Epot = gravity.potential_energy
Etot = Ekin + Epot
dE = Etot_init - Etot
# output centerd on the bodies[0] star
bodies.position -= bodies[0].position
bodies.velocity -= bodies[0].velocity
write_set_to_file(bodies, file_snap, "hdf5")
rel_r = (bodies[1].position - bodies[0].position).lengths()
print " \t\t", time, "\t", dE / Etot_init, rel_r.in_(units.AU)
time += dt
gravity.stop()
bodies.position -= bodies[0].position
bodies.velocity -= bodies[0].velocity
print bodies
return
def orbit_evolve(bodies, time_peri, eta, n_steps=100):
converter=nbody_system.nbody_to_si(1|units.MSun,1|units.AU)
gravity = Huayno(converter,channel_type="sockets")
gravity.particles.add_particles(bodies)
gravity.commit_particles()
gravity.parameters.timestep_parameter = eta
channel_from_gravity_to_framework = gravity.particles.new_channel_to(bodies)
Etot_init = gravity.kinetic_energy + gravity.potential_energy
Etot = Etot_init
file_snap = "orbit_ini.hdf5"
t_end = 2.0*abs(time_peri.value_in(units.yr)) | units.yr
dt = t_end / float(n_steps)
time = 0.0 | units.yr
while time <= t_end:
gravity.evolve_model(time)
channel_from_gravity_to_framework.copy()
bodies.age = time
# checking energy conservation
Ekin = gravity.kinetic_energy
Epot = gravity.potential_energy
Etot = Ekin + Epot
dE = Etot_init-Etot
# output centerd on the bodies[0] star
bodies.position -= bodies[0].position
bodies.velocity -= bodies[0].velocity
write_set_to_file(bodies, file_snap, "hdf5")
rel_r = (bodies[1].position - bodies[0].position).lengths()
print " \t\t", time, "\t", dE/Etot_init, rel_r.in_(units.AU)
time += dt
gravity.stop()
bodies.position -= bodies[0].position
bodies.velocity -= bodies[0].velocity
print bodies
return
def integrate_disk_flyby(stars, planetesimals, t_end, n_steps, snap_dir,
file_out, file_redir, huayno_eta):
converter = nbody_system.nbody_to_si(1 | units.MSun, 1 | units.AU)
planetesimals.position += stars[0].position
planetesimals.velocity += stars[0].velocity
bodies = ParticlesSuperset([stars, planetesimals])
if file_redir is None:
gravity = Huayno(converter, channel_type="sockets",
mode="openmp") # Add this (specify a number of cores)
elif file_redir == "0":
gravity = Huayno(converter,
channel_type="sockets",
redirection="none",
mode="openmp")
else:
gravity = Huayno(converter,
channel_type="sockets",
redirection="file",
redirect_file=file_redir,
mode="openmp")
gravity.particles.add_particles(bodies)
gravity.commit_particles()
gravity.parameters.timestep_parameter = huayno_eta
time_step = gravity.get_timestep_parameter()
#gravity.set_inttype_parameter(12)
#gravity.set_inttype_parameter(8)
gravity.set_eps2_parameter(0.001 * 0.001) # Softening Parameter
print ' ** timestep: ', gravity.get_timestep_parameter()
print ' ** inttype: ', gravity.get_inttype_parameter()
print ' ** eps2: ', gravity.get_eps2_parameter(), numpy.sqrt(
gravity.get_eps2_parameter())
t0 = time.time()
evolve_disk_flyby(bodies, gravity, t_end, n_steps, converter, snap_dir,
file_out)
t1 = time.time()
dt = t1 - t0
print "Performace data: N =", len(
bodies), "dt=", dt, "s =", dt / 60.0, "min"
return
def initialize_huayno(bodies, converter, huayno_eta):
""" initialize huayno code """
gravity = Huayno(converter,channel_type="sockets")
gravity.particles.add_particles(bodies) # either bodies or just stars
gravity.commit_particles()
#gravity.set_timestep_parameter(huayno_eta)
gravity.parameters.timestep_parameter = huayno_eta
gravity.set_inttype_parameter(8) # CC_KEPLER
"""
Huayno Options:
(pass / hold / bridge / maybe shared? are described in the Huayno Paper)
SHARED2=1
EXTRAPOLATE=5
PASS_KDK=2
PASS_DKD=7
HOLD_KDK=3
HOLD_DKD=8 <<<<-------
PPASS_DKD=9
BRIDGE_KDK=4
BRIDGE_DKD=10
CC=11
CC_KEPLER=12 <<<<-------
OK=13
KEPLER=14
SHARED4=15
SHARED6=18
SHARED8=19
SHARED10=20
SHAREDBS=21 **BS**
CCC=22
CCC_KEPLER=23
CC_BS=24 **BS**
CCC_BS=25 **BS**
BS_CC_KEPLER=26 **BS**
CC_BSA=27 **BS** ???
CCC_BSA=28 **BS** ???
SHARED2_COLLISIONS=29
SHARED4_COLLISIONS=30
SHARED6_COLLISIONS=31
SHARED8_COLLISIONS=32
SHARED10_COLLISIONS=33
"""
return gravity
def test7(self):
print("Test7: Testing effect of Huayno parameter epsilon_squared")
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun,
1.0 | units.AU)
particles = datamodel.Particles(2)
sun = particles[0]
sun.mass = 1.0 | units.MSun
sun.position = [0.0, 0.0, 0.0] | units.AU
sun.velocity = [0.0, 0.0, 0.0] | units.AU / units.yr
sun.radius = 1.0 | units.RSun
earth = particles[1]
earth.mass = 5.9736e24 | units.kg
earth.radius = 6371.0 | units.km
earth.position = [0.0, 1.0, 0.0] | units.AU
earth.velocity = [2.0 * numpy.pi, -0.0001, 0.0] | units.AU / units.yr
initial_direction = math.atan((earth.velocity[0] / earth.velocity[1]))
final_direction = []
for log_eps2 in range(-9, 10, 2):
instance = Huayno(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 10.0**log_eps2 | units.AU**2
instance.particles.add_particles(particles)
instance.commit_particles()
instance.evolve_model(0.25 | units.yr)
final_direction.append(
math.atan((instance.particles[1].velocity[0] /
instance.particles[1].velocity[1])))
instance.stop()
# Small values of epsilon_squared should result in normal earth-sun dynamics: rotation of 90 degrees
self.assertAlmostEqual(abs(final_direction[0]),
abs(initial_direction + math.pi / 2.0), 2)
# Large values of epsilon_squared should result in ~ no interaction
self.assertAlmostEqual(final_direction[-1], initial_direction, 2)
# Outcome is most sensitive to epsilon_squared when epsilon_squared = d(earth, sun)^2
delta = [
abs(final_direction[i + 1] - final_direction[i])
for i in range(len(final_direction) - 1)
]
self.assertEqual(delta[len(final_direction) // 2 - 1], max(delta))
def integrate_disk_flyby(stars, planetesimals, t_end, n_steps,
snap_dir, file_out, file_redir, huayno_eta):
converter=nbody_system.nbody_to_si(1|units.MSun,1|units.AU)
planetesimals.position += stars[0].position
planetesimals.velocity += stars[0].velocity
bodies = ParticlesSuperset([stars, planetesimals])
if file_redir is None:
gravity = Huayno(converter, channel_type="sockets",
mode="openmp") # Add this (specify a number of cores)
elif file_redir=="0":
gravity = Huayno(converter, channel_type="sockets", redirection="none",
mode="openmp")
else:
gravity = Huayno(converter, channel_type="sockets", redirection="file", redirect_file=file_redir,
mode="openmp")
gravity.particles.add_particles(bodies)
gravity.commit_particles()
gravity.parameters.timestep_parameter = huayno_eta
time_step = gravity.get_timestep_parameter()
#gravity.set_inttype_parameter(12)
#gravity.set_inttype_parameter(8)
gravity.set_eps2_parameter(0.001*0.001) # Softening Parameter
print ' ** timestep: ', gravity.get_timestep_parameter()
print ' ** inttype: ', gravity.get_inttype_parameter()
print ' ** eps2: ', gravity.get_eps2_parameter(), numpy.sqrt(gravity.get_eps2_parameter())
t0 = time.time()
evolve_disk_flyby(bodies, gravity,
t_end, n_steps, converter, snap_dir, file_out)
t1= time.time()
dt = t1-t0
print "Performace data: N =", len(bodies), "dt=", dt, "s =", dt/60.0, "min"
return
def test7(self):
print "Test7: Testing effect of Huayno parameter epsilon_squared"
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 1.0 | units.AU)
particles = datamodel.Particles(2)
sun = particles[0]
sun.mass = 1.0 | units.MSun
sun.position = [0.0, 0.0, 0.0] | units.AU
sun.velocity = [0.0, 0.0, 0.0] | units.AU / units.yr
sun.radius = 1.0 | units.RSun
earth = particles[1]
earth.mass = 5.9736e24 | units.kg
earth.radius = 6371.0 | units.km
earth.position = [0.0, 1.0, 0.0] | units.AU
earth.velocity = [2.0*numpy.pi, -0.0001, 0.0] | units.AU / units.yr
initial_direction = math.atan((earth.velocity[0]/earth.velocity[1]))
final_direction = []
for log_eps2 in range(-9,10,2):
instance = Huayno(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 10.0**log_eps2 | units.AU ** 2
instance.particles.add_particles(particles)
instance.commit_particles()
instance.evolve_model(0.25 | units.yr)
final_direction.append(math.atan((instance.particles[1].velocity[0]/
instance.particles[1].velocity[1])))
instance.stop()
# Small values of epsilon_squared should result in normal earth-sun dynamics: rotation of 90 degrees
self.assertAlmostEquals(abs(final_direction[0]), abs(initial_direction+math.pi/2.0), 2)
# Large values of epsilon_squared should result in ~ no interaction
self.assertAlmostEquals(final_direction[-1], initial_direction, 2)
# Outcome is most sensitive to epsilon_squared when epsilon_squared = d(earth, sun)^2
delta = [abs(final_direction[i+1]-final_direction[i]) for i in range(len(final_direction)-1)]
self.assertEquals(delta[len(final_direction)/2 -1], max(delta))
