def test23(self):
particles = datamodel.Particles(2)
particles.x = [0.0, 10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.vx = 1.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 0.1 | nbody_system.mass
instance = BHTree(redirection="none")
instance.particles.add_particles(particles)
instance.commit_particles()
instance.evolve_model(0.1 | nbody_system.time)
self.assertFalse(instance.particles[0].vy > 0 | nbody_system.speed)
self.assertAlmostRelativeEquals(instance.particles[0].x,
0.1 | nbody_system.length, 4)
instance.particles.new_channel_to(particles).copy()
particles.vy = 1 | nbody_system.speed
particles.new_channel_to(instance.particles).copy()
instance.evolve_model(0.2 | nbody_system.time)
self.assertTrue(instance.particles[0].vy > 0 | nbody_system.speed)
self.assertAlmostRelativeEquals(instance.particles[0].y,
0.1 | nbody_system.length, 4)
instance.stop()
def test11(self):
convert_nbody = nbody_system.nbody_to_si(5.0 | units.kg,
10.0 | units.m)
instance = BHTree(convert_nbody)
particles = datamodel.Particles(2)
self.assertEquals(len(instance.particles), 0)
particles.mass = [15.0, 30.0] | units.kg
particles.radius = [10.0, 20.0] | units.m
particles.position = [[10.0, 20.0, 30.0], [20.0, 40.0, 60.0]] | units.m
particles.velocity = [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]
] | units.m / units.s
instance.particles.add_particles(particles)
copyof = instance.particles.copy()
self.assertAlmostEqual(30 | units.kg, copyof[1].mass, 6)
copyof[1].mass = 35 | units.kg
copyof.copy_values_of_all_attributes_to(instance.particles)
self.assertAlmostEqual(35 | units.kg, instance.particles[1].mass, 6)
instance.stop()
def new_gas_code_bhtree(self):
result = BHTree(self.converter)
result.parameters.epsilon_squared = self.gas_epsilon ** 2
result.parameters.timestep = 0.125 * self.interaction_timestep
result.particles.add_particles(self.new_particles_cluster_as_gas())
result.commit_particles()
return result
def test1(self):
print "Test collect_required_attributes"
in_memory = self.new_colliders()
gravity = BHTree(nbody_system.nbody_to_si(1|units.MSun, 1.0|units.RSun))
gravity.particles.add_particles(in_memory)
stellar = SeBa()
stellar.particles.add_particles(in_memory)
collision = StellarEncounterInHydrodynamics(None, None, verbose=True)
self.assertFalse(hasattr(in_memory, "radius"))
collision.collect_required_attributes(in_memory, gravity, stellar)
self.assertTrue(hasattr(in_memory, "radius"))
self.assertAlmostRelativeEqual(in_memory.radius.sum(), 4.2458 | units.RSun, 3)
from_stellar = stellar.particles.copy()
for attribute in ["x", "y", "z", "vx", "vy", "vz"]:
self.assertFalse(hasattr(from_stellar, attribute))
collision.collect_required_attributes(from_stellar, gravity, stellar)
gravity.stop()
stellar.stop()
for attribute in ["x", "y", "z", "vx", "vy", "vz"]:
self.assertTrue(hasattr(from_stellar, attribute))
self.assertAlmostEqual(from_stellar.position, in_memory.position)
self.assertAlmostEqual(from_stellar.velocity, in_memory.velocity)
def test1(self):
print("Test collect_required_attributes")
in_memory = self.new_colliders()
gravity = BHTree(nbody_system.nbody_to_si(1|units.MSun, 1.0|units.RSun))
gravity.particles.add_particles(in_memory)
stellar = SeBa()
stellar.particles.add_particles(in_memory)
collision = StellarEncounterInHydrodynamics(None, None, verbose=True)
self.assertFalse(hasattr(in_memory, "radius"))
collision.collect_required_attributes(in_memory, gravity, stellar)
self.assertTrue(hasattr(in_memory, "radius"))
self.assertAlmostRelativeEqual(in_memory.radius.sum(), 4.2458 | units.RSun, 3)
from_stellar = stellar.particles.copy()
for attribute in ["x", "y", "z", "vx", "vy", "vz"]:
self.assertFalse(hasattr(from_stellar, attribute))
collision.collect_required_attributes(from_stellar, gravity, stellar)
gravity.stop()
stellar.stop()
for attribute in ["x", "y", "z", "vx", "vy", "vz"]:
self.assertTrue(hasattr(from_stellar, attribute))
self.assertAlmostEqual(from_stellar.position, in_memory.position)
self.assertAlmostEqual(from_stellar.velocity, in_memory.velocity)
def new_star_code_bhtree(self):
result = BHTree()
result.parameters.epsilon_squared = self.star_epsilon**2
result.parameters.timestep = 0.125 * self.interaction_timestep
result.particles.add_particles(self.new_particles_cluster())
result.commit_particles()
return result
def test22(self):
particles = datamodel.Particles(2)
particles.x = [0.0,10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.vx = 0.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
instance = BHTree()
instance.particles.add_particles(particles)
instance.commit_particles()
self.assertEquals(instance.particles[0].radius, 0.0 | nbody_system.length)
p = datamodel.Particle(
x = 1.0 | nbody_system.length,
y = 2.0 | nbody_system.length,
z = 3.0 | nbody_system.length,
vx = 1.0 | nbody_system.speed,
vy = 2.0 | nbody_system.speed,
vz = 3.0 | nbody_system.speed,
mass = 1.0 | nbody_system.mass,
radius = 4.0 | nbody_system.length,
)
instance.particles.add_particle(p)
self.assertEquals(instance.particles[0].radius, 0.0 | nbody_system.length)
self.assertEquals(instance.particles[1].radius, 0.0 | nbody_system.length)
self.assertEquals(instance.particles[2].radius, 4.0 | nbody_system.length)
instance.stop()
def setup_codes(stars_below_cut, stars_above_cut, nbody_converter):
if len(stars_below_cut) is 0: # direct
print "There are zero stars below the cut-off, using direct solver!"
gravity = Hermite(nbody_converter, number_of_workers=4)
gravity.particles.add_particles(stars_above_cut)
channels = Channels()
channels.add_channel(gravity.particles.new_channel_to(stars_above_cut))
return gravity, channels # NB no bridge needed
if len(stars_above_cut) is 0: # tree
print "There are zero stars above the cut-off, using tree solver!"
gravity = BHTree(nbody_converter)
gravity.particles.add_particles(stars_below_cut)
channels = Channels()
channels.add_channel(gravity.particles.new_channel_to(stars_below_cut))
return gravity, channels # NB no bridge needed
gravity_low_mass = BHTree(nbody_converter)
gravity_low_mass.particles.add_particles(stars_below_cut)
gravity_high_mass = Hermite(nbody_converter, number_of_workers=4)
gravity_high_mass.particles.add_particles(stars_above_cut)
bridge = Bridge(timestep=0.01|units.Myr, use_threading=False)
bridge.add_system(gravity_low_mass, (gravity_high_mass,))
bridge.add_system(gravity_high_mass, (gravity_low_mass,))
channels = Channels()
channels.add_channel(gravity_low_mass.particles.new_channel_to(stars_below_cut))
channels.add_channel(gravity_high_mass.particles.new_channel_to(stars_above_cut))
return bridge, channels
def test16(self):
numpy.random.seed(0)
number_of_stars = 2
stars = plummer.new_plummer_model(number_of_stars)
stars.radius = 0.00001 | nbody_system.length
stars.scale_to_standard()
instance = BHTree()
instance.initialize_code()
instance.parameters.epsilon_squared = (1.0 / 20.0 /
(number_of_stars**0.33333)
| nbody_system.length)**2
instance.parameters.timestep = 0.004 | nbody_system.time
instance.parameters.timestep = 0.00001 | nbody_system.time
instance.commit_parameters()
print instance.parameters.timestep
instance.particles.add_particles(stars)
instance.commit_particles()
energy_total_t0 = instance.potential_energy + instance.kinetic_energy
request = instance.evolve_model. async (1.0 | nbody_system.time)
request.result()
energy_total_t1 = instance.potential_energy + instance.kinetic_energy
self.assertAlmostRelativeEqual(energy_total_t0, energy_total_t1, 3)
instance.stop()
numpy.random.seed()
def test11(self):
convert_nbody = nbody_system.nbody_to_si(5.0 | units.kg, 10.0 | units.m)
instance = BHTree(convert_nbody)
particles = datamodel.Particles(2)
self.assertEquals(len(instance.particles), 0)
particles.mass = [15.0, 30.0] | units.kg
particles.radius = [10.0, 20.0] | units.m
particles.position = [[10.0, 20.0, 30.0], [20.0, 40.0, 60.0]] | units.m
particles.velocity = [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]] | units.m / units.s
instance.particles.add_particles(particles)
copyof = instance.particles.copy()
self.assertAlmostEqual(30 | units.kg, copyof[1].mass, 6)
copyof[1].mass = 35 | units.kg
copyof.copy_values_of_all_attributes_to(instance.particles)
self.assertAlmostEqual(35 | units.kg, instance.particles[1].mass, 6)
instance.stop()
def evolve_cluster_in_galaxy(N, W0, Rinit, tend, timestep, M, R):
R_galaxy = 0.1 | units.kpc
M_galaxy = 1.6e10 | units.MSun
converter = nbody_system.nbody_to_si(M_galaxy, R_galaxy)
galaxy = new_plummer_model(10000, convert_nbody=converter)
print "com:", galaxy.center_of_mass().in_(units.kpc)
print "comv:", galaxy.center_of_mass_velocity().in_(units.kms)
print len(galaxy)
galaxy_code = BHTree(converter, number_of_workers=2)
galaxy_code.parameters.epsilon_squared = (0.01 | units.kpc)**2
channe_to_galaxy = galaxy_code.particles.new_channel_to(galaxy)
channe_to_galaxy.copy()
galaxy_code.particles.add_particles(galaxy)
inner_stars = galaxy.select(lambda r: r.length() < Rinit, ["position"])
Minner = inner_stars.mass.sum()
print "Minner=", Minner.in_(units.MSun)
print "Ninner=", len(inner_stars)
vc_inner = (constants.G * Minner / Rinit).sqrt()
converter = nbody_system.nbody_to_si(Mcluster, Rcluster)
stars = new_king_model(N, W0, convert_nbody=converter)
masses = new_powerlaw_mass_distribution(N, 0.1 | units.MSun,
100 | units.MSun, -2.35)
stars.mass = masses
stars.scale_to_standard(converter)
stars.x += Rinit
stars.vy += 0.8 * vc_inner
cluster_code = ph4(converter, number_of_workers=2)
cluster_code.particles.add_particles(stars)
channel_to_stars = cluster_code.particles.new_channel_to(stars)
system = bridge(verbose=False)
system.add_system(cluster_code, (galaxy_code, ))
system.add_system(galaxy_code, (cluster_code, ))
system.timestep = 0.1 * timestep
times = quantities.arange(0 | units.Myr, tend, timestep)
for i, t in enumerate(times):
print "Time=", t.in_(units.Myr)
channe_to_galaxy.copy()
channel_to_stars.copy()
inner_stars = galaxy.select(lambda r: r.length() < Rinit, ["position"])
print "Minner=", inner_stars.mass.sum().in_(units.MSun)
system.evolve_model(t, timestep=timestep)
plot_galaxy_and_stars(galaxy, stars)
galaxy_code.stop()
cluster_code.stop()
def test14(self):
print "Test14: Testing BHTree parameters (I)"
convert_nbody = nbody_system.nbody_to_si(1.0 | units.yr, 1.0 | units.AU)
instance = BHTree(convert_nbody)
value,error = instance.legacy_interface.get_epsilon_squared()
self.assertEquals(0, error)
self.assertEquals(0.125, value)
self.assertAlmostEquals(0.125 | units.AU**2, instance.parameters.epsilon_squared, in_units=units.AU**2)
for x in [0.01, 0.1, 0.2]:
instance.parameters.epsilon_squared = x | units.AU**2
self.assertAlmostEquals(x | units.AU**2, instance.parameters.epsilon_squared, in_units=units.AU**2)
(value, error) = instance.legacy_interface.get_time_step()
self.assertEquals(0, error)
self.assertEquals(0.015625, value)
self.assertAlmostEquals(0.015625 | units.yr, instance.parameters.timestep, in_units=units.yr)
for x in [0.001, 0.01, 0.1]:
instance.parameters.timestep = x | units.yr
self.assertAlmostEquals(x | units.yr, instance.parameters.timestep, in_units=units.yr)
(value, error) = instance.legacy_interface.get_theta_for_tree()
self.assertEquals(0, error)
self.assertEquals(0.75, value)
self.assertEquals(0.75, instance.parameters.opening_angle)
for x in [0.2, 0.5, 0.7]:
instance.parameters.opening_angle = x
self.assertEquals(x, instance.parameters.opening_angle)
(value, error) = instance.legacy_interface.get_use_self_gravity()
self.assertEquals(0, error)
self.assertEquals(1, value)
self.assertEquals(1, instance.parameters.use_self_gravity)
for x in [0, 1]:
instance.parameters.use_self_gravity = x
self.assertEquals(x, instance.parameters.use_self_gravity)
(value, error) = instance.legacy_interface.get_ncrit_for_tree()
self.assertEquals(0, error)
self.assertEquals(12, value)
self.assertEquals(12, instance.parameters.ncrit_for_tree)
for x in [512, 2048, 4096]:
instance.parameters.ncrit_for_tree = x
self.assertEquals(x, instance.parameters.ncrit_for_tree)
(value, error) = instance.legacy_interface.get_dt_dia()
self.assertEquals(0, error)
self.assertEquals(1.0, value)
self.assertAlmostEquals(1.0 | units.yr, instance.parameters.dt_dia, in_units=units.yr)
for x in [0.1, 10.0, 100.0]:
instance.parameters.dt_dia = x | units.yr
self.assertAlmostEquals(x | units.yr, instance.parameters.dt_dia, in_units=units.yr)
instance.stop()
def evolve_cluster(cluster,mCut,dt,tend,mCluster,rCluster,dump=False,dump_dir='data_dump'):
if dump:
print('Will be saving data in:'+dump_dir)
converter=nbody_system.nbody_to_si(mCluster,rCluster)
# Splitting particle according to mass_cut
low_mass_stars = cluster.select(lambda m: m < mCut,["mass"])
high_mass_stars = cluster.select(lambda m: m >= mCut,["mass"])
# Sanity checks
print('Number of low-mass stars:',low_mass_stars.__len__())
print('Number of high-mass stars:',high_mass_stars.__len__())
# Making models and assigning particles
code_tree = BHTree(converter)
code_direct = ph4(converter)
code_tree.particles.add_particles(low_mass_stars)
code_direct.particles.add_particles(high_mass_stars)
channel_from_code_tree = code_tree.particles.new_channel_to(low_mass_stars)
channel_from_code_direct = code_direct.particles.new_channel_to(high_mass_stars)
# Making bridge
combined_gravity = bridge()
combined_gravity.add_system(code_tree,(code_direct,))
combined_gravity.add_system(code_direct,(code_tree,))
combined_gravity.timestep = dt
# Making first snapshot
#plot_cluster(low_mass_stars,high_mass_stars,'t=0',save=True)
# Evolving the model
times = quantities.arange(0|units.Myr, tend, dt)
mCut_str = str(mCut.value_in(units.MSun))
for i,t in enumerate(times):
print "Time=", t.in_(units.Myr)
channel_from_code_tree.copy()
channel_from_code_direct.copy()
combined_gravity.evolve_model(t, timestep=dt)
snapshot_name = 't_'+str(t.in_(units.Myr))
plot_cluster(low_mass_stars,high_mass_stars,snapshot_name,save=True)
time = str(t.value_in(units.Myr))
if dump:
pkl.dump(low_mass_stars,
open(dump_dir+'/t'+time+'_m'+mCut_str+'_low_mass.p',
'wb'))
pkl.dump(high_mass_stars,
open(dump_dir+'/t'+time+'_m'+mCut_str+'_high_mass.p',
'wb'))
code_tree.stop()
code_direct.stop()
def test17(self):
print "Testing BHTree collision_detection"
particles = datamodel.Particles(7)
particles.mass = 0.001 | nbody_system.mass
particles.radius = 0.01 | nbody_system.length
particles.x = [-101.0, -100.0, -0.5, 0.5, 100.0, 101.0, 104.0] | nbody_system.length
particles.y = 0 | nbody_system.length
particles.z = 0 | nbody_system.length
particles.velocity = [[2, 0, 0], [-2, 0, 0]]*3 + [[-4, 0, 0]] | nbody_system.speed
instance = BHTree(redirection='none')
instance.initialize_code()
instance.parameters.set_defaults()
# Uncommenting any of the following two lines will suppress collision detection
#~ instance.parameters.use_self_gravity = 0
#~ instance.parameters.epsilon_squared = 0.0 | nbody_system.length**2
instance.parameters.opening_angle = 0.1
instance.particles.add_particles(particles)
collisions = instance.stopping_conditions.collision_detection
collisions.enable()
instance.evolve_model(1.0 | nbody_system.time)
self.assertTrue(collisions.is_set())
self.assertTrue(instance.model_time < 0.5 | nbody_system.time)
self.assertEquals(len(collisions.particles(0)), 3)
self.assertEquals(len(collisions.particles(1)), 3)
self.assertEquals(len(particles - collisions.particles(0) - collisions.particles(1)), 1)
self.assertEquals(abs(collisions.particles(0).x - collisions.particles(1).x) <
(collisions.particles(0).radius + collisions.particles(1).radius),
[True, True, True])
sticky_merged = datamodel.Particles(len(collisions.particles(0)))
sticky_merged.mass = collisions.particles(0).mass + collisions.particles(1).mass
sticky_merged.radius = collisions.particles(0).radius
for p1, p2, merged in zip(collisions.particles(0), collisions.particles(1), sticky_merged):
merged.position = (p1 + p2).center_of_mass()
merged.velocity = (p1 + p2).center_of_mass_velocity()
print instance.model_time
print instance.particles
instance.particles.remove_particles(collisions.particles(0) + collisions.particles(1))
instance.particles.add_particles(sticky_merged)
instance.evolve_model(1.0 | nbody_system.time)
print
print instance.model_time
print instance.particles
self.assertTrue(collisions.is_set())
self.assertTrue(instance.model_time < 1.0 | nbody_system.time)
self.assertEquals(len(collisions.particles(0)), 1)
self.assertEquals(len(collisions.particles(1)), 1)
self.assertEquals(len(instance.particles - collisions.particles(0) - collisions.particles(1)), 2)
self.assertEquals(abs(collisions.particles(0).x - collisions.particles(1).x) <
(collisions.particles(0).radius + collisions.particles(1).radius),
[True])
instance.stop()
def evolve_cluster(cluster,mCut,dt,tend,mCluster,rCluster):
converter=nbody_system.nbody_to_si(mCluster,rCluster)
# Splitting particle according to mass_cut
low_mass_stars = cluster.select(lambda m: m < mCut,["mass"])
high_mass_stars = cluster.select(lambda m: m >= mCut,["mass"])
# Sanity checks
print('dynamical timescale:', cluster.dynamical_timescale().value_in(units.Myr))
print('Number of low-mass stars:',low_mass_stars.__len__())
print('Number of high-mass stars:',high_mass_stars.__len__())
#plot_cluster(low_mass_stars, high_mass_stars)
# Making models and assigning particles
code_tree = BHTree(converter)
code_direct = ph4(converter)
code_tree.particles.add_particles(low_mass_stars)
code_direct.particles.add_particles(high_mass_stars)
channel_from_code_tree = code_tree.particles.new_channel_to(low_mass_stars)
channel_from_code_direct = code_direct.particles.new_channel_to(high_mass_stars)
# Making bridge
combined_gravity = bridge()
combined_gravity.add_system(code_tree,(code_direct,))
combined_gravity.add_system(code_direct,(code_tree,))
combined_gravity.timestep = dt
# Evolving the model
time_series = []
half_mass_radii = []
core_radii = []
times = quantities.arange(0.|units.Myr, tend, dt)
for i,t in enumerate(times):
print "Time =", t.in_(units.Myr)
channel_from_code_tree.copy()
channel_from_code_direct.copy()
time_series.append(t.value_in(units.Myr))
pos,coreradius,coredens=cluster.densitycentre_coreradius_coredens(converter)
lr,mf=cluster.LagrangianRadii(converter) # outputs are radii, mass fractions
half_mass_radii.append(lr[5].value_in(units.parsec)) # 5th argument attributes to half-mass radius
core_radii.append(coreradius.value_in(units.parsec))
combined_gravity.evolve_model(t, timestep=dt)
code_tree.stop()
code_direct.stop()
# Plotting results
#plot_cluster(low_mass_stars, high_mass_stars)
# Plotting radii
plot_radii(time_series, half_mass_radii, x_label='time(Myr)', y_label='half-mass radius (pc)')
plot_radii(time_series, core_radii, x_label='time(Myr)', y_label='core radius (pc)')
def evolve_cluster_in_galaxy(N, W0, Rinit, tend, timestep, M, R):
R_galaxy=0.1 | units.kpc
M_galaxy=1.6e10 | units.MSun
converter=nbody_system.nbody_to_si(M_galaxy, R_galaxy)
galaxy=new_plummer_model(10000,convert_nbody=converter)
print "com:", galaxy.center_of_mass().in_(units.kpc)
print "comv:", galaxy.center_of_mass_velocity().in_(units.kms)
print len(galaxy)
galaxy_code = BHTree(converter, number_of_workers=2)
galaxy_code.parameters.epsilon_squared = (0.01 | units.kpc)**2
channe_to_galaxy = galaxy_code.particles.new_channel_to(galaxy)
channe_to_galaxy.copy()
galaxy_code.particles.add_particles(galaxy)
inner_stars = galaxy.select(lambda r: r.length()<Rinit,["position"])
Minner = inner_stars.mass.sum()
print "Minner=", Minner.in_(units.MSun)
print "Ninner=", len(inner_stars)
vc_inner = (constants.G*Minner/Rinit).sqrt()
converter=nbody_system.nbody_to_si(Mcluster,Rcluster)
stars=new_king_model(N,W0,convert_nbody=converter)
masses = new_powerlaw_mass_distribution(N, 0.1|units.MSun, 100|units.MSun, -2.35)
stars.mass = masses
stars.scale_to_standard(converter)
stars.x += Rinit
stars.vy += 0.8*vc_inner
cluster_code=ph4(converter, number_of_workers=2)
cluster_code.particles.add_particles(stars)
channel_to_stars=cluster_code.particles.new_channel_to(stars)
system=bridge(verbose=False)
system.add_system(cluster_code, (galaxy_code,))
system.add_system(galaxy_code, (cluster_code,))
system.timestep = 0.1*timestep
times = quantities.arange(0|units.Myr, tend, timestep)
for i,t in enumerate(times):
print "Time=", t.in_(units.Myr)
channe_to_galaxy.copy()
channel_to_stars.copy()
inner_stars = galaxy.select(lambda r: r.length()<Rinit,["position"])
print "Minner=", inner_stars.mass.sum().in_(units.MSun)
system.evolve_model(t,timestep=timestep)
plot_galaxy_and_stars(galaxy, stars)
galaxy_code.stop()
cluster_code.stop()
def test20(self):
particles = datamodel.Particles(2)
particles.x = [0.0, 10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = 0.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
very_short_time_to_evolve = 1 | units.s
very_long_time_to_evolve = 1e9 | nbody_system.time
instance = BHTree()
instance.initialize_code()
instance.parameters.stopping_conditions_timeout = very_short_time_to_evolve
self.assertEquals(instance.parameters.stopping_conditions_timeout,
very_short_time_to_evolve)
instance.parameters.epsilon_squared = (0.01 | nbody_system.length)**2
instance.particles.add_particles(particles)
codeparticles1 = instance.particles
instance.particles.add_particle(
datamodel.Particle(position=[0, 1, 2] | nbody_system.length,
velocity=[0, 0, 0] | nbody_system.speed,
radius=0.005 | nbody_system.length,
mass=1 | nbody_system.mass))
codeparticles2 = instance.particles
self.assertTrue(codeparticles1 is codeparticles2)
instance.cleanup_code()
codeparticles3 = instance.particles
self.assertFalse(codeparticles1 is codeparticles3)
instance.stop()
def test19(self):
particles = datamodel.Particles(2)
particles.x = [0.0, 10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = 0.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
very_short_time_to_evolve = 1 | units.s
very_long_time_to_evolve = 1e9 | nbody_system.time
instance = BHTree()
instance.initialize_code()
instance.parameters.stopping_conditions_timeout = very_short_time_to_evolve
self.assertEquals(instance.parameters.stopping_conditions_timeout,
very_short_time_to_evolve)
instance.parameters.epsilon_squared = (0.01 | nbody_system.length)**2
instance.particles.add_particles(particles)
instance.stopping_conditions.timeout_detection.enable()
start = time.time()
instance.evolve_model(very_long_time_to_evolve)
end = time.time()
self.assertTrue(
instance.stopping_conditions.timeout_detection.is_set())
self.assertTrue(
(end - start) < very_short_time_to_evolve.value_in(units.s) +
2) #2 = some overhead compensation
instance.stop()
def test13(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.kg, 1.0 | units.m)
instance = BHTree(convert_nbody)
instance.commit_parameters()
particles = datamodel.Particles(2)
self.assertEquals(len(instance.particles), 0)
particles.mass = [30.0, 30.0] | units.kg
particles.radius = [1.0, 1.0] | units.m
particles.position = [[-10.0, 0.0, 0.0], [10.0, 0.0, 0.0]] | units.m
particles.velocity = [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]
] | units.m / units.s
instance.particles.add_particles(particles)
instance.commit_particles()
copyof = instance.particles.copy()
com = instance.center_of_mass_position
self.assertAlmostEqual(com[0], quantities.new_quantity(0.0, units.m),
constants.precision)
instance.stop()
def test19(self):
particles = datamodel.Particles(2)
particles.x = [0.0,10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = 0.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
very_short_time_to_evolve = 1 | units.s
very_long_time_to_evolve = 1e9 | nbody_system.time
instance = BHTree()
instance.initialize_code()
instance.parameters.stopping_conditions_timeout = very_short_time_to_evolve
self.assertEquals(instance.parameters.stopping_conditions_timeout, very_short_time_to_evolve)
instance.parameters.epsilon_squared = (0.01 | nbody_system.length)**2
instance.particles.add_particles(particles)
instance.stopping_conditions.timeout_detection.enable()
start = time.time()
instance.evolve_model(very_long_time_to_evolve)
end = time.time()
self.assertTrue(instance.stopping_conditions.timeout_detection.is_set())
self.assertTrue((end-start) < very_short_time_to_evolve.value_in(units.s) + 2)#2 = some overhead compensation
instance.stop()
def test20(self):
particles = datamodel.Particles(2)
particles.x = [0.0,10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = 0.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
very_short_time_to_evolve = 1 | units.s
very_long_time_to_evolve = 1e9 | nbody_system.time
instance = BHTree()
instance.initialize_code()
instance.parameters.stopping_conditions_timeout = very_short_time_to_evolve
self.assertEquals(instance.parameters.stopping_conditions_timeout, very_short_time_to_evolve)
instance.parameters.epsilon_squared = (0.01 | nbody_system.length)**2
instance.particles.add_particles(particles)
codeparticles1 = instance.particles
instance.particles.add_particle(datamodel.Particle(
position = [0,1,2] | nbody_system.length,
velocity = [0,0,0] | nbody_system.speed,
radius = 0.005 | nbody_system.length,
mass = 1 | nbody_system.mass
))
codeparticles2 = instance.particles
self.assertTrue(codeparticles1 is codeparticles2)
instance.cleanup_code()
codeparticles3 = instance.particles
self.assertFalse(codeparticles1 is codeparticles3)
instance.stop()
def test15(self):
print "Test15: Testing effect of BHTree 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 = BHTree(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))
def nbody_integrator(Ncl, mcl, rcl, t_end, n_steps, escape_velocity_fraction, R):
converter = nbody_system.nbody_to_si(mcl, rcl)
bodies = new_plummer_model(Ncl, convert_nbody=converter)
#estimate of milky way mass by "Mass models of the Milky Way", McMillan
blackhole_mass = 1.26e12 | units.MSun
blackhole = Particle(mass=blackhole_mass)
blackhole.position = [0,0,0] | units.m
cluster_velocity = [0,0,0] | units.m / units.s
cluster_position = [0,0,0] | units.parsec
cluster_position[0] = R
G_si = converter.to_si(nbody_system.G)
escape_v = (2*G_si*blackhole_mass/R).sqrt().as_quantity_in(units.m/units.s)
V = escape_v * escape_velocity_fraction
cluster_velocity[1] = V
bodies.move_to_center()
bodies.velocity += cluster_velocity
bodies.position += cluster_position
bodies.add_particle(blackhole)
gravity = BHTree(converter)
gravity.particles.add_particles(bodies)
channel_from_gravity_to_framework = gravity.particles.\
new_channel_to(bodies)
time = zero
dt = t_end / float(n_steps)
x = 0
base_path = "encounter_plots/"+str(R.value_in(units.parsec))+"_"+\
str(escape_velocity_fraction)+"_"
while time < t_end:
plot_cluster(bodies, base_path+str(x),time, rcl, V)
time += dt
gravity.evolve_model(time)
channel_from_gravity_to_framework.copy()
x+=1
plot_cluster(bodies, base_path+str(x),time, rcl, V)
gravity.stop()
return V, bodies
def sub_worker(parts):
mode=system_type(parts)
if mode=="twobody":
#code=TwoBody(conv_sub)
code=ph4(conv_sub)
elif mode=="solarsystem":
#code=Mercury(conv_sub)
code=Huayno(conv_sub)
elif mode=="nbody":
code=BHTree(conv_sub)
#code.parameters.inttype_parameter=code.inttypes.SHARED4
return code
def test22(self):
particles = datamodel.Particles(2)
particles.x = [0.0, 10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.vx = 0.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
instance = BHTree()
instance.particles.add_particles(particles)
instance.commit_particles()
self.assertEquals(instance.particles[0].radius,
0.0 | nbody_system.length)
p = datamodel.Particle(
x=1.0 | nbody_system.length,
y=2.0 | nbody_system.length,
z=3.0 | nbody_system.length,
vx=1.0 | nbody_system.speed,
vy=2.0 | nbody_system.speed,
vz=3.0 | nbody_system.speed,
mass=1.0 | nbody_system.mass,
radius=4.0 | nbody_system.length,
)
instance.particles.add_particle(p)
self.assertEquals(instance.particles[0].radius,
0.0 | nbody_system.length)
self.assertEquals(instance.particles[1].radius,
0.0 | nbody_system.length)
self.assertEquals(instance.particles[2].radius,
4.0 | nbody_system.length)
instance.stop()
def parent_worker():
Mgalaxy, Rgalaxy = float(
6.8e10
) | units.MSun, 2.6 | units.kpc #disk mass for MWPotential2014, Bovy(2015)
converter_parent = nbody_system.nbody_to_si(Mgalaxy, Rgalaxy)
code = BHTree(converter_parent) #done in src_nemesis
#code.parameters.epsilon_squared=0.| units.kpc**2
#code.parameters.end_time_accuracy_factor=0.
#code.parameters.dt_param=0.1
return code
def test9(self):
instance = BHTree()
instance.initialize_code()
instance.parameters.epsilon_squared = 0.00001 | nbody_system.length**2
particles = datamodel.Particles(2)
particles.mass = [1.0, 1.0] | nbody_system.mass
particles.radius = [0.0001, 0.0001] | nbody_system.length
particles.position = [[0.0,0.0,0.0], [2.0,0.0,0.0]] | nbody_system.length
particles.velocity = [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]] | nbody_system.speed
instance.particles.add_particles(particles)
zero = 0.0 | nbody_system.length
fx, fy, fz = instance.get_gravity_at_point(zero, 1.0 | nbody_system.length, zero, zero)
self.assertAlmostEqual(fx, 0.0 | nbody_system.acceleration, 3)
self.assertAlmostEqual(fy, 0.0 | nbody_system.acceleration, 3)
self.assertAlmostEqual(fz, 0.0 | nbody_system.acceleration, 3)
for x in (0.25, 0.5, 0.75):
x0 = x | nbody_system.length
x1 = (2.0 - x) | nbody_system.length
potential0 = instance.get_potential_at_point(zero, x0, zero, zero)
potential1 = instance.get_potential_at_point(zero, x1, zero, zero)
fx0, fy0, fz0 = instance.get_gravity_at_point(zero, x0, zero, zero)
fx1, fy1, fz1 = instance.get_gravity_at_point(zero, x1, zero, zero)
self.assertAlmostEqual(fy0, 0.0 | nbody_system.acceleration, 3)
self.assertAlmostEqual(fz0, 0.0 | nbody_system.acceleration, 3)
self.assertAlmostEqual(fy1, 0.0 | nbody_system.acceleration, 3)
self.assertAlmostEqual(fz1, 0.0 | nbody_system.acceleration, 3)
self.assertAlmostEqual(fx0, -1.0 * fx1, 5)
fx = (-1.0 / (x0**2) + 1.0 / (x1**2)) * (1.0 | nbody_system.length ** 3 / nbody_system.time ** 2)
self.assertAlmostEqual(fx, fx0, 2)
self.assertAlmostEqual(potential0, potential1, 5)
instance.cleanup_code()
instance.stop()
def test8(self):
convert_nbody = nbody_system.nbody_to_si(5.0 | units.kg, 10.0 | units.m)
instance = BHTree(convert_nbody)
instance.commit_parameters()
particles = datamodel.Particles(2)
self.assertEquals(len(instance.particles), 0)
particles.mass = [15.0, 30.0] | units.kg
particles.radius = [10.0, 20.0] | units.m
particles.position = [[10.0, 20.0, 30.0], [20.0, 40.0, 60.0]] | units.m
particles.velocity = [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]] | units.m / units.s
instance.particles.add_particles(particles)
instance.commit_particles()
instance.particles.mass = [17.0, 33.0] | units.kg
self.assertEquals(instance.get_mass(1), 17.0| units.kg)
instance.cleanup_code()
instance.stop()
def setup_codes(stars_below_cut, stars_above_cut, nbody_converter):
gravity_low_mass = BHTree(nbody_converter)
gravity_low_mass.particles.add_particles(stars_below_cut)
gravity_high_mass = Hermite(nbody_converter)
gravity_high_mass.particles.add_particles(stars_above_cut)
bridge = Bridge(timestep=0.01|units.Myr, use_threading=False)
bridge.add_system(gravity_low_mass, (gravity_high_mass,))
bridge.add_system(gravity_high_mass, (gravity_low_mass,))
channels = Channels()
channels.add_channel(gravity_low_mass.particles.new_channel_to(stars_below_cut))
channels.add_channel(gravity_high_mass.particles.new_channel_to(stars_above_cut))
return gravity_low_mass, gravity_high_mass, bridge, channels
def setup_codes(cluster, gas, nbody_converter, gas_converter):
gravity = BHTree(nbody_converter)
gravity.particles.add_particles(cluster)
hydro = Fi(gas_converter)
hydro.parameters.eps_is_h_flag = True
hydro.parameters.timestep = 0.005 | units.Myr
hydro.particles.add_particles(gas)
bridge = Bridge(timestep=0.01 | units.Myr, use_threading=False)
bridge.add_system(gravity, (hydro, ))
bridge.add_system(hydro, (gravity, ))
channels = Channels()
channels.add_channel(gravity.particles.new_channel_to(cluster))
channels.add_channel(hydro.particles.new_channel_to(gas))
return gravity, hydro, bridge, channels
def test16(self):
numpy.random.seed(0)
number_of_stars = 2
stars = plummer.new_plummer_model(number_of_stars)
stars.radius = 0.00001 | nbody_system.length
stars.scale_to_standard()
instance = BHTree()
instance.initialize_code()
instance.parameters.epsilon_squared = (1.0 / 20.0 / (number_of_stars**0.33333) | nbody_system.length)**2
instance.parameters.timestep = 0.004 | nbody_system.time
instance.parameters.timestep = 0.00001 | nbody_system.time
instance.commit_parameters()
print instance.parameters.timestep
instance.particles.add_particles(stars)
instance.commit_particles()
energy_total_t0 = instance.potential_energy + instance.kinetic_energy
request = instance.evolve_model.async(1.0 | nbody_system.time)
request.result()
energy_total_t1 = instance.potential_energy + instance.kinetic_energy
self.assertAlmostRelativeEqual(energy_total_t0, energy_total_t1, 3)
instance.stop()
numpy.random.seed()
def test15(self):
print "Test15: Testing effect of BHTree 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 = BHTree(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))
def test23(self):
particles = datamodel.Particles(2)
particles.x = [0.0,10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.vx = 1.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 0.1 | nbody_system.mass
instance = BHTree(redirection="none")
instance.particles.add_particles(particles)
instance.commit_particles()
instance.evolve_model(0.1 | nbody_system.time)
self.assertFalse(instance.particles[0].vy > 0| nbody_system.speed)
self.assertAlmostRelativeEquals(instance.particles[0].x , 0.1 | nbody_system.length, 4)
instance.particles.new_channel_to(particles).copy()
particles.vy = 1| nbody_system.speed
particles.new_channel_to(instance.particles).copy()
instance.evolve_model(0.2 | nbody_system.time)
self.assertTrue(instance.particles[0].vy > 0| nbody_system.speed)
self.assertAlmostRelativeEquals(instance.particles[0].y , 0.1 | nbody_system.length, 4)
instance.stop()
def test_bhtree(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.kg, 1.0 | units.km)
bhtree = BHTree(convert_nbody)
bhtree.parameters.epsilon_squared = 10 | units.km**2
bhtree.parameters.timestep = 1.0 | units.s
bhtree.parameters.opening_angle = 0.1
docstring = bhtree.parameters.__doc__
self.assertTrue("smoothing parameter for gravity calculations (default value:125000.0 m**2)" in docstring)
parameter_str_method_output = str(bhtree.parameters)
self.assertTrue("epsilon_squared: 10000000.0 m**2" in parameter_str_method_output)
self.assertTrue("timestep: 1.0 s" in parameter_str_method_output)
self.assertTrue("opening_angle: 0.1" in parameter_str_method_output)
def test21(self):
particles = datamodel.Particles(2)
particles.x = [0.0, 10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = 0.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
very_short_time_to_evolve = 1 | units.s
very_long_time_to_evolve = 1e9 | nbody_system.time
instance = BHTree()
instance.initialize_code()
instance.parameters.epsilon_squared = (1e-5 | nbody_system.length)**2
instance.particles.add_particles(particles)
instance.commit_particles()
self.assertAlmostRelativeEquals(instance.potential_energy,
-0.1 | nbody_system.energy, 5)
instance.stop()
def test18(self):
particles = datamodel.Particles(2)
particles.x = [0.0, 10.0] | nbody_system.length
particles.y = 0 | nbody_system.length
particles.z = 0 | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = 0 | nbody_system.speed
particles.vy = 0 | nbody_system.speed
particles.vz = 0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
instance = BHTree()
instance.initialize_code()
instance.parameters.stopping_conditions_number_of_steps = 2
self.assertEquals(
instance.parameters.stopping_conditions_number_of_steps, 2)
instance.parameters.epsilon_squared = (0.01 | nbody_system.length)**2
instance.particles.add_particles(particles)
instance.stopping_conditions.number_of_steps_detection.enable()
instance.evolve_model(10 | nbody_system.time)
self.assertTrue(
instance.stopping_conditions.number_of_steps_detection.is_set())
self.assertTrue(instance.model_time < 10 | nbody_system.time)
instance.stop()
def test21(self):
particles = datamodel.Particles(2)
particles.x = [0.0,10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = 0.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
very_short_time_to_evolve = 1 | units.s
very_long_time_to_evolve = 1e9 | nbody_system.time
instance = BHTree()
instance.initialize_code()
instance.parameters.epsilon_squared = (1e-5 | nbody_system.length)**2
instance.particles.add_particles(particles)
instance.commit_particles()
self.assertAlmostRelativeEquals(instance.potential_energy, -0.1 | nbody_system.energy, 5)
instance.stop()
def test18(self):
particles = datamodel.Particles(2)
particles.x = [0.0,10.0] | nbody_system.length
particles.y = 0 | nbody_system.length
particles.z = 0 | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = 0 | nbody_system.speed
particles.vy = 0 | nbody_system.speed
particles.vz = 0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
instance = BHTree()
instance.initialize_code()
instance.parameters.stopping_conditions_number_of_steps = 2
self.assertEquals(instance.parameters.stopping_conditions_number_of_steps, 2)
instance.parameters.epsilon_squared = (0.01 | nbody_system.length)**2
instance.particles.add_particles(particles)
instance.stopping_conditions.number_of_steps_detection.enable()
instance.evolve_model(10 | nbody_system.time)
self.assertTrue(instance.stopping_conditions.number_of_steps_detection.is_set())
self.assertTrue(instance.model_time < 10 | nbody_system.time)
instance.stop()
def init_integrator(method):
if method == 'octgrav':
gravity = Octgrav()
elif method == 'ph4':
gravity = ph4()
elif method == 'fi':
gravity = Fi(convert_nbody)
gravity.initialize_code()
gravity.parameters.epsilon_squared = 0.00000001 | units.AU**2
gravity.parameters.timestep = .10 | units.day
elif method == 'phigrape':
gravity = PhiGRAPE(convert_nbody, mode=PhiGRAPEInterface.MODE_GPU)
elif method == 'bhtree':
gravity = BHTree(convert_nbody, number_of_workes=workers)
elif method == 'hermite':
gravity = Hermite(convert_nbody,
number_of_workers=workers
#debugger = "xterm",
#redirection = "none"
)
gravity.parameters.epsilon_squared = 0.00001 | units.AU**2
return gravity
def nbody_integrator(Ncl, mcl, rcl, t_end, n_steps, escape_velocity_fraction,
R):
converter = nbody_system.nbody_to_si(mcl, rcl)
bodies = new_plummer_model(Ncl, convert_nbody=converter)
#estimate of milky way mass by "Mass models of the Milky Way", McMillan
blackhole_mass = 1.26e12 | units.MSun
blackhole = Particle(mass=blackhole_mass)
blackhole.position = [0, 0, 0] | units.m
cluster_velocity = [0, 0, 0] | units.m / units.s
cluster_position = [0, 0, 0] | units.parsec
cluster_position[0] = R
G_si = converter.to_si(nbody_system.G)
escape_v = (2 * G_si * blackhole_mass / R).sqrt().as_quantity_in(units.m /
units.s)
V = escape_v * escape_velocity_fraction
cluster_velocity[1] = V
bodies.move_to_center()
bodies.velocity += cluster_velocity
bodies.position += cluster_position
bodies.add_particle(blackhole)
gravity = BHTree(converter)
gravity.particles.add_particles(bodies)
channel_from_gravity_to_framework = gravity.particles.\
new_channel_to(bodies)
time = zero
dt = t_end / float(n_steps)
x = 0
base_path = "encounter_plots/"+str(R.value_in(units.parsec))+"_"+\
str(escape_velocity_fraction)+"_"
while time < t_end:
plot_cluster(bodies, base_path + str(x), time, rcl, V)
time += dt
gravity.evolve_model(time)
channel_from_gravity_to_framework.copy()
x += 1
plot_cluster(bodies, base_path + str(x), time, rcl, V)
gravity.stop()
return V, bodies
def test13(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.kg, 1.0 | units.m)
instance = BHTree(convert_nbody)
instance.commit_parameters()
particles = datamodel.Particles(2)
self.assertEquals(len(instance.particles), 0)
particles.mass = [30.0, 30.0] | units.kg
particles.radius = [1.0, 1.0] | units.m
particles.position = [[-10.0, 0.0, 0.0], [10.0, 0.0, 0.0]] | units.m
particles.velocity = [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]] | units.m / units.s
instance.particles.add_particles(particles)
instance.commit_particles()
copyof = instance.particles.copy()
com = instance.center_of_mass_position
self.assertAlmostEqual(com[0], quantities.new_quantity(0.0, units.m), constants.precision)
instance.stop()
def new_code_to_calculate_gravity_of_gas_particles():
result = BHTree(self.converter)
return result
def test3(self):
instance = BHTree()
self._run_addition_removal_test(instance)
def test14(self):
print "Test14: Testing BHTree parameters (I)"
convert_nbody = nbody_system.nbody_to_si(1.0 | units.yr,
1.0 | units.AU)
instance = BHTree(convert_nbody)
value, error = instance.legacy_interface.get_epsilon_squared()
self.assertEquals(0, error)
self.assertEquals(0.125, value)
self.assertAlmostEquals(0.125 | units.AU**2,
instance.parameters.epsilon_squared,
in_units=units.AU**2)
for x in [0.01, 0.1, 0.2]:
instance.parameters.epsilon_squared = x | units.AU**2
self.assertAlmostEquals(x | units.AU**2,
instance.parameters.epsilon_squared,
in_units=units.AU**2)
(value, error) = instance.legacy_interface.get_time_step()
self.assertEquals(0, error)
self.assertEquals(0.015625, value)
self.assertAlmostEquals(0.015625 | units.yr,
instance.parameters.timestep,
in_units=units.yr)
for x in [0.001, 0.01, 0.1]:
instance.parameters.timestep = x | units.yr
self.assertAlmostEquals(x | units.yr,
instance.parameters.timestep,
in_units=units.yr)
(value, error) = instance.legacy_interface.get_theta_for_tree()
self.assertEquals(0, error)
self.assertEquals(0.75, value)
self.assertEquals(0.75, instance.parameters.opening_angle)
for x in [0.2, 0.5, 0.7]:
instance.parameters.opening_angle = x
self.assertEquals(x, instance.parameters.opening_angle)
(value, error) = instance.legacy_interface.get_use_self_gravity()
self.assertEquals(0, error)
self.assertEquals(1, value)
self.assertEquals(1, instance.parameters.use_self_gravity)
for x in [0, 1]:
instance.parameters.use_self_gravity = x
self.assertEquals(x, instance.parameters.use_self_gravity)
(value, error) = instance.legacy_interface.get_ncrit_for_tree()
self.assertEquals(0, error)
self.assertEquals(12, value)
self.assertEquals(12, instance.parameters.ncrit_for_tree)
for x in [512, 2048, 4096]:
instance.parameters.ncrit_for_tree = x
self.assertEquals(x, instance.parameters.ncrit_for_tree)
(value, error) = instance.legacy_interface.get_dt_dia()
self.assertEquals(0, error)
self.assertEquals(1.0, value)
self.assertAlmostEquals(1.0 | units.yr,
instance.parameters.dt_dia,
in_units=units.yr)
for x in [0.1, 10.0, 100.0]:
instance.parameters.dt_dia = x | units.yr
self.assertAlmostEquals(x | units.yr,
instance.parameters.dt_dia,
in_units=units.yr)
instance.stop()
def test12(self):
convert_nbody = nbody_system.nbody_to_si(5.0 | units.kg,
10.0 | units.m)
instance = BHTree(convert_nbody)
instance.commit_parameters()
particles = datamodel.Particles(2)
self.assertEquals(len(instance.particles), 0)
particles.mass = [15.0, 30.0] | units.kg
particles.radius = [10.0, 20.0] | units.m
particles.position = [[10.0, 20.0, 30.0], [20.0, 40.0, 60.0]] | units.m
particles.velocity = [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]
] | units.m / units.s
instance.particles.add_particles(particles)
instance.commit_particles()
copyof = instance.particles.copy()
instance.set_state(1, 16 | units.kg, 20.0 | units.m, 40.0 | units.m,
60.0 | units.m, 1.0 | units.ms, 1.0 | units.ms,
1.0 | units.ms)
curr_state = instance.get_state(1)
for expected, actual in zip(
(16 | units.kg, 20.0 | units.m, 40.0 | units.m, 60.0 | units.m,
1.0 | units.ms, 1.0 | units.ms, 1.0 | units.ms, 0 | units.m),
curr_state):
self.assertAlmostRelativeEquals(actual, expected)
instance.set_state(1, 16 | units.kg, 20.0 | units.m, 40.0 | units.m,
60.0 | units.m, 1.0 | units.ms, 1.0 | units.ms,
1.0 | units.ms, 20.0 | units.m)
curr_state = instance.get_state(1)
for expected, actual in zip(
(16 | units.kg, 20.0 | units.m, 40.0 | units.m, 60.0 | units.m,
1.0 | units.ms, 1.0 | units.ms, 1.0 | units.ms, 20 | units.m),
curr_state):
self.assertAlmostRelativeEquals(actual, expected)
instance.stop()
def simulate_small_cluster(number_of_stars,
end_time=40 | units.Myr,
name_of_the_figure="test-2.svg"):
# numpy.random.seed(1)
salpeter_masses = new_salpeter_mass_distribution(number_of_stars)
total_mass = salpeter_masses.sum()
convert_nbody = nbody_system.nbody_to_si(total_mass, 1.0 | units.parsec)
particles = new_plummer_model(number_of_stars, convert_nbody)
gravity = BHTree(convert_nbody)
# print gravity.parameters.timestep.as_quantity_in(units.Myr)
gravity.parameters.timestep = 0.0001 | units.Myr # tiny!
gravity.parameters.epsilon_squared \
= (float(number_of_stars)**(-0.333333) | units.parsec) ** 2
stellar_evolution = SSE()
print "setting masses of the stars"
particles.radius = 0.0 | units.RSun
particles.mass = salpeter_masses
print "initializing the particles"
stellar_evolution.particles.add_particles(particles)
from_stellar_evolution_to_model \
= stellar_evolution.particles.new_channel_to(particles)
from_stellar_evolution_to_model.copy_attributes(["mass"])
print "centering the particles"
particles.move_to_center()
print "scaling particles to viridial equilibrium"
particles.scale_to_standard(convert_nbody)
gravity.particles.add_particles(particles)
from_model_to_gravity = particles.new_channel_to(gravity.particles)
from_gravity_to_model = gravity.particles.new_channel_to(particles)
time = 0.0 | units.Myr
particles.savepoint(time)
total_energy_at_t0 = gravity.kinetic_energy + gravity.potential_energy
print "evolving the model until t = " + str(end_time)
while time < end_time:
time += 0.25 | units.Myr
print "gravity evolve step starting"
gravity.evolve_model(time)
print "gravity evolve step done"
print "stellar evolution step starting"
stellar_evolution.evolve_model(time)
print "stellar evolution step done"
from_gravity_to_model.copy()
from_stellar_evolution_to_model.copy_attributes(["mass", "radius"])
particles.savepoint(time)
from_model_to_gravity.copy_attributes(["mass"])
total_energy_at_this_time \
= gravity.kinetic_energy + gravity.potential_energy
print_log(time, gravity, particles, total_energy_at_t0,
total_energy_at_this_time)
test_results_path = get_path_to_results()
output_file = os.path.join(test_results_path, "small.hdf5")
if os.path.exists(output_file):
os.remove(output_file)
storage = store.StoreHDF(output_file)
storage.store(particles)
gravity.stop()
stellar_evolution.stop()
plot_particles(particles, name_of_the_figure)
def test17(self):
print "Testing BHTree collision_detection"
particles = datamodel.Particles(7)
particles.mass = 0.001 | nbody_system.mass
particles.radius = 0.01 | nbody_system.length
particles.x = [-101.0, -100.0, -0.5, 0.5, 100.0, 101.0, 104.0
] | nbody_system.length
particles.y = 0 | nbody_system.length
particles.z = 0 | nbody_system.length
particles.velocity = [[2, 0, 0], [-2, 0, 0]
] * 3 + [[-4, 0, 0]] | nbody_system.speed
instance = BHTree(redirection='none')
instance.initialize_code()
instance.parameters.set_defaults()
# Uncommenting any of the following two lines will suppress collision detection
#~ instance.parameters.use_self_gravity = 0
#~ instance.parameters.epsilon_squared = 0.0 | nbody_system.length**2
instance.parameters.opening_angle = 0.1
instance.particles.add_particles(particles)
collisions = instance.stopping_conditions.collision_detection
collisions.enable()
instance.evolve_model(1.0 | nbody_system.time)
self.assertTrue(collisions.is_set())
self.assertTrue(instance.model_time < 0.5 | nbody_system.time)
self.assertEquals(len(collisions.particles(0)), 3)
self.assertEquals(len(collisions.particles(1)), 3)
self.assertEquals(
len(particles - collisions.particles(0) - collisions.particles(1)),
1)
self.assertEquals(
abs(collisions.particles(0).x - collisions.particles(1).x) <
(collisions.particles(0).radius + collisions.particles(1).radius),
[True, True, True])
sticky_merged = datamodel.Particles(len(collisions.particles(0)))
sticky_merged.mass = collisions.particles(
0).mass + collisions.particles(1).mass
sticky_merged.radius = collisions.particles(0).radius
for p1, p2, merged in zip(collisions.particles(0),
collisions.particles(1), sticky_merged):
merged.position = (p1 + p2).center_of_mass()
merged.velocity = (p1 + p2).center_of_mass_velocity()
print instance.model_time
print instance.particles
instance.particles.remove_particles(
collisions.particles(0) + collisions.particles(1))
instance.particles.add_particles(sticky_merged)
instance.evolve_model(1.0 | nbody_system.time)
print
print instance.model_time
print instance.particles
self.assertTrue(collisions.is_set())
self.assertTrue(instance.model_time < 1.0 | nbody_system.time)
self.assertEquals(len(collisions.particles(0)), 1)
self.assertEquals(len(collisions.particles(1)), 1)
self.assertEquals(
len(instance.particles - collisions.particles(0) -
collisions.particles(1)), 2)
self.assertEquals(
abs(collisions.particles(0).x - collisions.particles(1).x) <
(collisions.particles(0).radius + collisions.particles(1).radius),
[True])
instance.stop()
def test12(self):
convert_nbody = nbody_system.nbody_to_si(5.0 | units.kg, 10.0 | units.m)
instance = BHTree(convert_nbody)
instance.commit_parameters()
particles = datamodel.Particles(2)
self.assertEquals(len(instance.particles), 0)
particles.mass = [15.0, 30.0] | units.kg
particles.radius = [10.0, 20.0] | units.m
particles.position = [[10.0, 20.0, 30.0], [20.0, 40.0, 60.0]] | units.m
particles.velocity = [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]] | units.m / units.s
instance.particles.add_particles(particles)
instance.commit_particles()
copyof = instance.particles.copy()
instance.set_state(1, 16|units.kg, 20.0|units.m, 40.0|units.m, 60.0|units.m,
1.0|units.ms, 1.0|units.ms, 1.0|units.ms)
curr_state = instance.get_state(1)
for expected, actual in zip((16|units.kg, 20.0|units.m, 40.0|units.m, 60.0|units.m,
1.0|units.ms, 1.0|units.ms, 1.0|units.ms, 0 | units.m), curr_state):
self.assertAlmostRelativeEquals(actual,expected)
instance.set_state(1, 16|units.kg, 20.0|units.m, 40.0|units.m, 60.0|units.m,
1.0|units.ms, 1.0|units.ms, 1.0|units.ms , 20.0|units.m)
curr_state = instance.get_state(1)
for expected, actual in zip((16|units.kg, 20.0|units.m, 40.0|units.m, 60.0|units.m,
1.0|units.ms, 1.0|units.ms, 1.0|units.ms, 20 | units.m), curr_state):
self.assertAlmostRelativeEquals(actual,expected)
instance.stop()
def assignment_2d():
current_cluster_mass = 400 | units.MSun
initial_mass_fraction = 0.84
desired_initial_mass = current_cluster_mass / initial_mass_fraction
masses = new_salpeter_mass_distribution(100000)
mean_salpeter_mass = masses.mean()
print "mean salpeter mass", mean_salpeter_mass
N = int(desired_initial_mass / mean_salpeter_mass)
print "N", N
Rvir = 10 | units.lightyear
z = 0.17
masses = new_salpeter_mass_distribution(N)
converter = nbody_system.nbody_to_si(masses.sum(), Rvir)
G_SI = converter.to_si(nbody_system.G)
bodies = new_plummer_sphere(N, convert_nbody=converter)
bodies.mass = masses
bodies.metalicity = z
# start the gravity solver
gravity = BHTree(converter)
gravity.initialize_code()
gravity.parameters.timestep = 0.1 | units.Myr
# start the stellar evolution solver
stellar = SSE()
stars = stellar.particles.add_particles(bodies)
from_stellar_evolution_to_model \
= stellar.particles.new_channel_to(bodies)
from_stellar_evolution_to_model.copy_attributes(["mass"])
bodies.scale_to_standard(converter)
gravity.particles.add_particles(bodies)
from_model_to_gravity = bodies.new_channel_to(gravity.particles)
from_gravity_to_model = gravity.particles.new_channel_to(bodies)
gravity.commit_particles()
end_time = 1000 | units.Myr
current_time = 0 | units.Myr
cluster = "Hyades"
bound_stars_counts = []
main_sequence_stars_counts = []
giant_stars_counts = []
remnant_stars_counts = []
max_radii = [] | units.parsec
virial_radii = [] | units.parsec
times = [] | units.Myr
while current_time < end_time:
name_of_the_figure = "isochrone_with_grav_"+str(int(current_time.value_in(units.Myr)))+".png"
gravity.evolve_model(current_time)
stellar.evolve_model(current_time)
from_gravity_to_model.copy()
from_stellar_evolution_to_model.copy_attributes(["mass", "radius"])
from_model_to_gravity.copy_attributes(["mass"])
remnant_count = 0
main_sequence_count = 0
giant_count = 0
for star in stars:
if stellar_remnant_state(star):
remnant_count += 1
if stellar_giant_state(star):
giant_count += 1
if stellar_main_sequence_state(star):
main_sequence_count += 1
max_radius = bodies.total_radius()
virial_radius = bodies.virial_radius()
bound_star_count = len(bodies.bound_subset(unit_converter=converter, G=G_SI))
print "bound stars:", bound_star_count
print "main sequence stars:", main_sequence_count
print "giant stars:", giant_count
print "remnant stars:", remnant_count
print "cluster radius(max from centre):", max_radius
print "virial radius:", virial_radius
print current_time
times.append(current_time)
remnant_stars_counts.append(remnant_count)
giant_stars_counts.append(giant_count)
main_sequence_stars_counts.append(main_sequence_count)
max_radii.append(max_radius)
virial_radii.append(virial_radius)
bound_stars_counts.append(bound_star_count)
temperatures = stars.temperature
luminosities = stars.luminosity
plot_HR_diagram(temperatures, luminosities,
cluster+"/",
name_of_the_figure, current_time)
current_time += 10 | units.Myr
data = {}
data["bound_stars_at_time"] = bound_stars_counts
data["remnant_stars_at_time"] = remnant_stars_counts
data["giant_stars_at_time"] = giant_stars_counts
data["main_sequence_stars_at_time"] = main_sequence_stars_counts
data["max_radius_at_time"] = max_radii
data["virial_radii"] = virial_radii
data["times"] = times
pickle.dump(data, open(cluster+"/assignment2d.dat", "wb"))
def test1(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = BHTree(convert_nbody)
instance.parameters.epsilon_squared = 0.001 | units.AU**2
stars = datamodel.Stars(2)
sun = stars[0]
sun.mass = units.MSun(1.0)
sun.position = [0.0,0.0,0.0] | units.m
sun.velocity = [0.0,0.0,0.0] | units.ms
sun.radius = units.RSun(1.0)
earth = stars[1]
earth.mass = units.kg(5.9736e24)
earth.radius = units.km(6371)
earth.position = [149.5e6, 0.0, 0.0] | units.km
earth.velocity = [0.0, 29800, 0.0] | units.ms
#instance.particles.add_particles(stars)
instance.particles.add_particles(stars)
postion_at_start = earth.position.value_in(units.AU)[0]
instance.evolve_model(365.0 | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
postion_after_full_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostEqual(postion_at_start, postion_after_full_rotation, 3)
instance.evolve_model(365.0 + (365.0 / 2) | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
postion_after_half_a_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostEqual(-postion_at_start, postion_after_half_a_rotation, 2)
instance.evolve_model(365.0 + (365.0 / 2) + (365.0 / 4) | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
postion_after_half_a_rotation = earth.position.value_in(units.AU)[1]
self.assertAlmostEqual(-postion_at_start, postion_after_half_a_rotation, 1)
instance.cleanup_code()
instance.stop()
def test2(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
bhtree = BHTree(convert_nbody)
bhtree.initialize_code()
bhtree.eps2_for_gravity = 0.001
bhtree_particles = self.new_system_sun_and_earth()
bhtree.particles.add_particles(bhtree_particles)
if bhtree.legacy_interface.channel_type == 'mpi':
from mpi4py import MPI
if not MPI.Query_thread() == MPI.THREAD_MULTIPLE:
bhtree.stop()
self.skip("can only test parallel with multiple thread support in mpi implementation")
hermite = Hermite(convert_nbody)
hermite.dt_dia = 5000
hermite.commit_parameters()
hermite_particles = self.new_system_sun_and_earth()
hermite.particles.add_particles(hermite_particles)
thread1 = threading.Thread(target = self.evolve_model_unit_day, args = (bhtree, bhtree_particles, 10))
thread2 = threading.Thread(target = self.evolve_model_unit_day, args = (hermite, hermite_particles, 10))
thread1.start()
thread2.start()
thread1.join()
thread2.join()
if HAS_MATPLOTLIB:
figure = pyplot.figure()
plot = figure.add_subplot(1,1,1)
earth = bhtree_particles[1]
x_points = earth.get_timeline_of_attribute("x")
y_points = earth.get_timeline_of_attribute("y")
x_points_in_AU = map(lambda (t,x) : x.value_in(units.AU), x_points)
y_points_in_AU = map(lambda (t,x) : x.value_in(units.AU), y_points)
plot.scatter(x_points_in_AU,y_points_in_AU, color = "b", marker = 'o')
earth = hermite_particles[1]
x_points = earth.get_timeline_of_attribute("x")
y_points = earth.get_timeline_of_attribute("y")
x_points_in_AU = map(lambda (t,x) : x.value_in(units.AU), x_points)
y_points_in_AU = map(lambda (t,x) : x.value_in(units.AU), y_points)
plot.scatter(x_points_in_AU,y_points_in_AU, color = "g", marker = 'o')
plot.set_xlim(-1.5, 1.5)
plot.set_ylim(-1.5, 1.5)
test_results_path = self.get_path_to_results()
output_file = os.path.join(test_results_path, "parallel-earth-sun.svg")
figure.savefig(output_file)
bhtree.stop()
hermite.stop()
bhtree.stop()
def test3(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = BHTree(convert_nbody)
#instance.dt_dia = 1
instance.parameters.epsilon_squared = 0.001 | units.AU**2
#instance.timestep = 0.0001
#instance.use_self_gravity = 0
instance.commit_parameters()
stars = datamodel.Stars(2)
star1 = stars[0]
star2 = stars[1]
star1.mass = units.MSun(1.0)
star1.position = units.AU(numpy.array((-.10,0.0,0.0)))
star1.velocity = units.AUd(numpy.array((0.0,0.0,0.0)))
star1.radius = units.RSun(1.0)
star2.mass = units.MSun(1.0)
star2.position = units.AU(numpy.array((.10,0.0,0.0)))
star2.velocity = units.AUd(numpy.array((0.0,0.0,0.0)))
star2.radius = units.RSun(100.0)
instance.particles.add_particles(stars)
instance.commit_particles()
for x in range(1,200,1):
instance.evolve_model(x | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
#instance.get_indices_of_colliding_particles()
#print stars[0].position-stars[1].position
stars.savepoint()
instance.cleanup_code()
instance.stop()
def test4(self):
convert_nbody = nbody_system.nbody_to_si(5.0 | units.kg, 10.0 | units.m)
instance = BHTree(convert_nbody)
instance.commit_parameters()
index = instance.new_particle(
15.0 | units.kg,
10.0 | units.m, 20.0 | units.m, 30.0 | units.m,
#1.0 | units.m/units.s, 1.0 | units.m/units.s, 3.0 | units.m/units.s
0.0 | units.m/units.s, 0.0 | units.m/units.s, 0.0 | units.m/units.s,
10.0 | units.m
)
instance.commit_particles()
self.assertEquals(instance.get_mass(index), 15.0| units.kg)
self.assertEquals(instance.get_radius(index), 10.0| units.m)
instance.cleanup_code()
instance.stop()
def test5(self):
instance = BHTree()
instance.commit_parameters()
index = instance.new_particle(
15.0 | nbody_system.mass,
10.0 | nbody_system.length, 20.0 | nbody_system.length, 30.0 | nbody_system.length,
1.0 | nbody_system.speed, 1.0 | nbody_system.speed, 3.0 | nbody_system.speed,
10.0 | nbody_system.length
)
instance.commit_particles()
self.assertEquals(instance.get_mass(index), 15.0| nbody_system.mass)
self.assertEquals(instance.get_radius(index), 10.0| nbody_system.length)
instance.cleanup_code()
instance.stop()
def test6(self):
convert_nbody = nbody_system.nbody_to_si(5.0 | units.kg, 10.0 | units.m)
instance = BHTree(convert_nbody)
instance.commit_parameters()
indices = instance.new_particle(
[15.0, 30.0] | units.kg,
[10.0, 20.0] | units.m, [20.0, 40.0] | units.m, [30.0, 50.0] | units.m,
#1.0 | units.m/units.s, 1.0 | units.m/units.s, 3.0 | units.m/units.s
[0.0, 0.01] | units.m/units.s, [0.0, 0.01] | units.m/units.s, [0.0, 0.01] | units.m/units.s,
[10.0, 20.0] | units.m
)
instance.commit_particles()
self.assertEquals(instance.get_mass(indices[0]), 15.0| units.kg)
self.assertEquals(instance.get_mass(indices)[0], 15.0| units.kg)
self.assertRaises(AmuseException, instance.get_mass, [4,5],
expected_message = "Error when calling 'get_mass' of a 'BHTree', errorcode is -1")
instance.cleanup_code()
instance.stop()
def test10(self):
instance = BHTree()
instance.initialize_code()
instance.parameters.epsilon_squared = 0.00001 | nbody_system.length**2
instance.commit_parameters()
particles = datamodel.Particles(6)
particles.mass = 1.0 | nbody_system.mass
particles.radius = 0.00001 | nbody_system.length
particles.position = [[-1.0,0.0,0.0],[1.0,0.0,0.0],[0.0,-1.0,0.0],[0.0,1.0,0.0],[0.0,0.0,-1.0],[0.0,0.0,1.0]] | nbody_system.length
particles.velocity = [[0.0,0.0,0.0],[0.0,0.0,0.0],[0.0,0.0,0.0],[0.0,0.0,0.0],[0.0,0.0,0.0],[0.0,0.0,0.0]] | nbody_system.speed
instance.particles.add_particles(particles)
instance.commit_particles()
zero = 0.0 | nbody_system.length
fx, fy, fz = instance.get_gravity_at_point(zero, zero, zero, zero)
self.assertAlmostEqual(fx, 0.0 | nbody_system.acceleration, 3)
self.assertAlmostEqual(fy, 0.0 | nbody_system.acceleration, 3)
self.assertAlmostEqual(fz, 0.0 | nbody_system.acceleration, 3)
for position in (0.25, 0.5, 0.75):
p0 = position | nbody_system.length
p1 = -position | nbody_system.length
for i in range(3):
args0 = [zero] * 4
args1 = [zero] * 4
args0[1 + i] = p0
args1[1 + i] = p1
f0 = instance.get_gravity_at_point(*args0)
f1 = instance.get_gravity_at_point(*args1)
for j in range(3):
if j != i:
self.assertAlmostEqual(f0[j], 0.0 | nbody_system.acceleration, 3)
self.assertAlmostEqual(f1[j], 0.0 | nbody_system.acceleration, 3)
else:
self.assertAlmostEqual(f0[j], -1.0 * f1[j], 5)
instance.stop()
def test2(self):
#not completed
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = BHTree(convert_nbody)
#instance.dt_dia = 1
instance.parameters.epsilon_squared = 0.001 | units.AU**2
#instance.timestep = 0.0001
#instance.use_self_gravity = 0
instance.commit_parameters()
stars = datamodel.Stars(2)
sun = stars[0]
sun.mass = units.MSun(1.0)
sun.position = units.m(numpy.array((0.0,0.0,0.0)))
sun.velocity = units.ms(numpy.array((0.0,0.0,0.0)))
sun.radius = units.RSun(1.0)
earth = stars[1]
earth.mass = units.kg(5.9736e24)
earth.radius = units.km(6371)
earth.position = units.km(numpy.array((149.5e6,0.0,0.0)))
earth.velocity = units.ms(numpy.array((0.0,29800,0.0)))
instance.particles.add_particles(stars)
instance.commit_particles()
self.assertAlmostRelativeEquals(sun.radius, instance.particles[0].radius)
for x in range(1,2000,10):
instance.evolve_model(x | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
stars.savepoint()
if HAS_MATPLOTLIB:
figure = pyplot.figure()
plot = figure.add_subplot(1,1,1)
x_points = earth.get_timeline_of_attribute("x")
y_points = earth.get_timeline_of_attribute("y")
x_points_in_AU = map(lambda (t,x) : x.value_in(units.AU), x_points)
y_points_in_AU = map(lambda (t,x) : x.value_in(units.AU), y_points)
plot.scatter(x_points_in_AU,y_points_in_AU, color = "b", marker = 'o')
plot.set_xlim(-1.5, 1.5)
plot.set_ylim(-1.5, 1.5)
test_results_path = self.get_path_to_results()
output_file = os.path.join(test_results_path, "bhtree-earth-sun.svg")
figure.savefig(output_file)
instance.cleanup_code()
instance.stop()
def simulate_small_cluster(number_of_stars, end_time=40 | units.Myr,
name_of_the_figure="test-2.svg"):
# numpy.random.seed(1)
salpeter_masses = new_salpeter_mass_distribution(number_of_stars)
total_mass = salpeter_masses.sum()
convert_nbody = nbody_system.nbody_to_si(total_mass, 1.0 | units.parsec)
particles = new_plummer_model(number_of_stars, convert_nbody)
gravity = BHTree(convert_nbody)
gravity.initialize_code()
# gravity.parameters.set_defaults()
# print gravity.parameters.timestep.as_quantity_in(units.Myr)
gravity.parameters.timestep = 0.0001 | units.Myr # tiny!
gravity.parameters.epsilon_squared \
= (float(number_of_stars)**(-0.333333) | units.parsec) ** 2
stellar_evolution = SSE()
stellar_evolution.initialize_module_with_default_parameters()
print "setting masses of the stars"
particles.radius = 0.0 | units.RSun
particles.mass = salpeter_masses
print "initializing the particles"
stellar_evolution.particles.add_particles(particles)
from_stellar_evolution_to_model \
= stellar_evolution.particles.new_channel_to(particles)
from_stellar_evolution_to_model.copy_attributes(["mass"])
print "centering the particles"
particles.move_to_center()
print "scaling particles to viridial equilibrium"
particles.scale_to_standard(convert_nbody)
gravity.particles.add_particles(particles)
from_model_to_gravity = particles.new_channel_to(gravity.particles)
from_gravity_to_model = gravity.particles.new_channel_to(particles)
gravity.commit_particles()
time = 0.0 | units.Myr
particles.savepoint(time)
total_energy_at_t0 = gravity.kinetic_energy + gravity.potential_energy
print "evolving the model until t = " + str(end_time)
while time < end_time:
time += 0.25 | units.Myr
print "Gravity evolve step starting"
gravity_evolve = gravity.evolve_model.async(time)
print "Stellar evolution step starting"
stellar_evolution_evolve = stellar_evolution.evolve_model(time)
print "Stellar evolution step done."
gravity_evolve.result()
print "Gravity evolve step done."
from_gravity_to_model.copy()
from_stellar_evolution_to_model.copy_attributes(["mass", "radius"])
particles.savepoint(time)
from_model_to_gravity.copy_attributes(["mass"])
total_energy_at_this_time \
= gravity.kinetic_energy + gravity.potential_energy
print_log(time, gravity, particles,
total_energy_at_t0, total_energy_at_this_time)
test_results_path = get_path_to_results()
output_file = os.path.join(test_results_path, "small.hdf5")
if os.path.exists(output_file):
os.remove(output_file)
storage = store.StoreHDF(output_file)
storage.store(particles)
gravity.stop()
stellar_evolution.stop()
plot_particles(particles, name_of_the_figure)
