def test22(self):
particles = new_plummer_model(200)
particles.scale_to_standard()
try:
instance = ph4(mode="gpu")
except:
self.skip("gpu mode is not available")
instance.initialize_code()
instance.parameters.epsilon_squared = 0.00000 | nbody_system.length ** 2
instance.particles.add_particles(particles)
x = numpy.arange(-1, 1, 0.1) | nbody_system.length
zero = numpy.zeros(len(x)) | nbody_system.length
gpu_potential = instance.get_potential_at_point(zero, x, zero, zero)
instance.stop()
instance = ph4()
instance.initialize_code()
instance.parameters.epsilon_squared = 0.00000 | nbody_system.length ** 2
instance.particles.add_particles(particles)
nogpu_potential = instance.get_potential_at_point(zero, x, zero, zero)
self.assertAlmostRelativeEquals(nogpu_potential, gpu_potential, 5)
instance.stop()
def test16(self):
print "Testing ph4 states"
stars = new_plummer_model(100)
black_hole = datamodel.Particle()
black_hole.mass = 1.0 | nbody_system.mass
black_hole.radius = 0.0 | nbody_system.length
black_hole.position = [0.0, 0.0, 0.0] | nbody_system.length
black_hole.velocity = [0.0, 0.0, 0.0] | nbody_system.speed
print "First do everything manually:"
instance = ph4()
self.assertEquals(instance.get_name_of_current_state(), 'UNINITIALIZED')
instance.initialize_code()
self.assertEquals(instance.get_name_of_current_state(), 'INITIALIZED')
instance.parameters.epsilon_squared = 0.0 | nbody_system.length**2
instance.parameters.timestep_parameter = 0.01
instance.commit_parameters()
self.assertEquals(instance.get_name_of_current_state(), 'EDIT')
instance.particles.add_particles(stars)
instance.commit_particles()
self.assertEquals(instance.get_name_of_current_state(), 'RUN')
instance.particles.remove_particle(stars[0])
instance.particles.add_particle(black_hole)
self.assertEquals(instance.get_name_of_current_state(), 'UPDATE')
instance.recommit_particles()
self.assertEquals(instance.get_name_of_current_state(), 'RUN')
instance.evolve_model(0.001 | nbody_system.time)
self.assertEquals(instance.get_name_of_current_state(), 'EVOLVED')
instance.synchronize_model()
self.assertEquals(instance.get_name_of_current_state(), 'RUN')
instance.cleanup_code()
self.assertEquals(instance.get_name_of_current_state(), 'END')
instance.stop()
print "initialize_code(), commit_parameters(), (re)commit_particles(), " \
"synchronize_model(), and cleanup_code() should be called " \
"automatically before editing parameters, new_particle(), get_xx(), and stop():"
instance = ph4()
self.assertEquals(instance.get_name_of_current_state(), 'UNINITIALIZED')
instance.parameters.epsilon_squared = 0.0 | nbody_system.length**2
instance.parameters.timestep_parameter = 0.01
self.assertEquals(instance.get_name_of_current_state(), 'INITIALIZED')
instance.particles.add_particles(stars)
self.assertEquals(instance.get_name_of_current_state(), 'EDIT')
mass = instance.particles[0].mass
self.assertEquals(instance.get_name_of_current_state(), 'RUN')
instance.particles.remove_particle(stars[0])
instance.particles.add_particle(black_hole)
self.assertEquals(instance.get_name_of_current_state(), 'UPDATE')
mass = instance.particles[0].mass
self.assertEquals(instance.get_name_of_current_state(), 'RUN')
instance.evolve_model(0.001 | nbody_system.time)
self.assertEquals(instance.get_name_of_current_state(), 'EVOLVED')
mass = instance.particles[0].mass
self.assertEquals(instance.get_name_of_current_state(), 'RUN')
instance.stop()
self.assertEquals(instance.get_name_of_current_state(), 'STOPPED')
def test27(self):
print "Testing get timestep of particles"
with_softening = True
particles = datamodel.Particles(7)
particles.mass = 0.1 | nbody_system.mass
particles.radius = 0.01 | nbody_system.length
particles.x = [-101.0, -100.0, -2.0, 2.0, 98.0, 102.0, 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 + [[-5, 0, 0]] | nbody_system.speed
total_energy = particles.potential_energy(G=nbody_system.G) + particles.kinetic_energy()
instance = ph4()
instance.initialize_code()
instance.parameters.set_defaults()
if with_softening:
print "small amount of softening will prevent timesteps far below 1e-6 and huge energy errors..."
instance.parameters.epsilon_squared = 1.0e-10 | nbody_system.length**2
instance.particles.add_particles(particles)
for target_time, min_dt, n_digits in zip([0, 0.23, 0.24, 0.26, 0.27]|nbody_system.time,
[0.5**10, 0.5**11, 0.5**20, 0.5**10, 0.5**10]|nbody_system.time,
[10, 7, 4, 5, 5]):
instance.evolve_model(target_time)
if with_softening:
self.assertEquals(instance.particles.timestep.amin(), min_dt)
self.assertAlmostRelativeEquals(instance.potential_energy + instance.kinetic_energy, total_energy, n_digits)
else:
print "\ntarget_time:", target_time
print "minimum timestep:", instance.particles.timestep.amin()
print "energy error:", (instance.potential_energy + instance.kinetic_energy - total_energy) / total_energy
total_energy = instance.potential_energy + instance.kinetic_energy
instance.stop()
def test3(self):
convert_nbody = nbody_system.nbody_to_si(5.0 | units.kg, 10.0 | units.m)
instance = ph4(convert_nbody)
instance.initialize_code()
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)
self.assertEquals(len(instance.particles), 2)
instance.commit_particles()
instance.particles.mass = [17.0, 33.0] | units.kg
self.assertEquals(instance.get_mass(1), 17.0 | units.kg)
self.assertEquals(instance.get_mass(2), 33.0 | units.kg)
instance.cleanup_code()
instance.stop()
def xtest12(self):
particles = datamodel.Particles(2)
particles.x = [
0.0,
1.0,
# 5,7,
# 10,12,
# 15,17,
# 20,22
] | nbody_system.length
particles.y = 0 | nbody_system.length
particles.z = 0 | nbody_system.length
particles.radius = 0.75 | 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 = ph4()
instance.initialize_code()
instance.parameters.epsilon_squared = (0.01 | nbody_system.length) ** 2
instance.particles.add_particles(particles)
instance.stopping_conditions.pair_detection.enable()
instance.evolve_model(1.5 | nbody_system.time)
self.assertTrue(instance.stopping_conditions.pair_detection.is_set())
self.assertEquals(len(instance.stopping_conditions.pair_detection.particles(0)), 2)
p0 = instance.stopping_conditions.pair_detection.particles(0)[0]
p1 = instance.stopping_conditions.pair_detection.particles(1)[0]
self.assertNotEquals(p0, p1)
self.assertTrue(p1.x - p0.x < 1.5 | nbody_system.length)
instance.stop()
def xtest14(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
very_short_time_to_evolve = 1 | units.s
very_long_time_to_evolve = 1e9 | nbody_system.time
instance = ph4()
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 xtest8(self):
particles = datamodel.Particles(6)
particles.mass = nbody_system.mass.new_quantity(range(1, 7))
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
for current_mode in ["gpu"]:
try:
instance = ph4(mode=current_mode)
except:
print "Running PhiGRAPE with mode=", current_mode, " was unsuccessful."
else:
print "Running PhiGRAPE with mode=", current_mode, "... ",
instance.initialize_code()
instance.particles.add_particles(particles)
instance.initialize_particles(0.0)
instance.evolve_model(0.1 | nbody_system.time)
instance.cleanup_code()
instance.stop()
print "ok"
def xtest7(self):
instance = ph4()
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | nbody_system.length ** 2
instance.set_eta(0.01, 0.02)
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)
instance.initialize_particles(0.0)
zero = [0.0, 0.0, 0.0] | nbody_system.length
fx, fy, fz = instance.get_gravity_at_point(zero, [0.5, 1.0, 1.5] | nbody_system.length, zero, zero)
self.assertAlmostRelativeEqual(fx[0], -3.55555555556 | nbody_system.acceleration, 5)
self.assertAlmostRelativeEqual(fy[0], 0.0 | nbody_system.acceleration, 3)
self.assertAlmostRelativeEqual(fz[0], 0.0 | nbody_system.acceleration, 3)
self.assertAlmostRelativeEqual(fx[1], 0.0 | nbody_system.acceleration, 3)
self.assertAlmostRelativeEqual(fy[1], 0.0 | nbody_system.acceleration, 3)
self.assertAlmostRelativeEqual(fz[1], 0.0 | nbody_system.acceleration, 3)
self.assertAlmostRelativeEqual(fx[2], 3.55555555556 | nbody_system.acceleration, 5)
self.assertAlmostRelativeEqual(fy[2], 0.0 | nbody_system.acceleration, 3)
self.assertAlmostRelativeEqual(fz[2], 0.0 | nbody_system.acceleration, 3)
n = 512
x = nbody_system.length.new_quantity(numpy.linspace(0.1, 1.9, n))
zero = nbody_system.length.new_quantity(numpy.zeros(n))
fx, fy, fz = instance.get_gravity_at_point(zero, x, zero, zero)
for i in range(n / 2):
self.assertAlmostRelativeEqual(fx[i], -fx[n - 1 - i], 5)
instance.stop()
def test18(self):
print "Testing effect of ph4 parameter epsilon_squared"
converter = nbody_system.nbody_to_si(1.0 | units.MSun, 1.0 | units.AU)
particles = datamodel.Particles(2)
particles.mass = [1.0, 3.0037e-6] | units.MSun
particles.radius = 1.0 | units.RSun
particles.position = [[0.0, 0.0, 0.0], [1.0, 0.0, 0.0]] | units.AU
particles.velocity = [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]] | units.km / units.s
particles[1].vy = (constants.G * particles.total_mass() / (1.0 | units.AU)).sqrt()
particles.rotate(0.0, 0.0, math.pi / 4)
particles.move_to_center()
tan_initial_direction = particles[1].vy / particles[1].vx
self.assertAlmostEquals(tan_initial_direction, math.tan(-math.pi / 4))
tan_final_direction = []
for log_eps2 in range(-5, 6, 2):
instance = ph4(converter)
instance.initialize_code()
instance.parameters.epsilon_squared = 10.0 ** log_eps2 | units.AU ** 2
instance.parameters.timestep_parameter = 0.001
instance.commit_parameters()
instance.particles.add_particles(particles)
instance.commit_particles()
instance.evolve_model(0.25 | units.yr)
tan_final_direction.append(instance.particles[1].velocity[1] / instance.particles[1].velocity[0])
instance.cleanup_code()
instance.stop()
# Small values of epsilon_squared should result in normal earth-sun dynamics: rotation of 90 degrees
self.assertAlmostEquals(tan_final_direction[0], math.tan(math.pi / 4.0), 2)
# Large values of epsilon_squared should result in ~ no interaction
self.assertAlmostEquals(tan_final_direction[-1], tan_initial_direction, 2)
# Outcome is most sensitive to epsilon_squared when epsilon_squared = d(earth, sun)^2
delta = [abs(tan_final_direction[i + 1] - tan_final_direction[i]) for i in range(len(tan_final_direction) - 1)]
self.assertEquals(delta[len(tan_final_direction) // 2 - 1], max(delta))
def test19(self):
print "Testing ph4 properties"
particles = new_plummer_model(1000, do_scale=True)
particles.position += [1, 2, 3] | nbody_system.length
cluster_velocity = [4, 5, 6] | nbody_system.speed
particles.velocity += cluster_velocity
external_kinetic_energy = (0.5 | nbody_system.mass) * cluster_velocity.length_squared()
instance = ph4()
instance.particles.add_particles(particles)
kinetic_energy = instance.kinetic_energy - external_kinetic_energy
potential_energy = instance.potential_energy
self.assertAlmostRelativeEqual(kinetic_energy, 0.25 | nbody_system.energy, 10)
self.assertAlmostRelativeEqual(potential_energy, -0.5 | nbody_system.energy, 10)
self.assertAlmostRelativeEqual(instance.total_mass, 1.0 | nbody_system.mass, 10)
self.assertAlmostRelativeEqual(instance.center_of_mass_position, [1, 2, 3] | nbody_system.length, 10)
self.assertAlmostRelativeEqual(instance.center_of_mass_velocity, [4, 5, 6] | nbody_system.speed, 10)
initial_total_energy = kinetic_energy + potential_energy
instance.evolve_model(0.1 | nbody_system.time)
self.assertAlmostRelativeEqual(instance.model_time, 0.1 | nbody_system.time, 3)
kinetic_energy = instance.kinetic_energy - external_kinetic_energy
potential_energy = instance.potential_energy
self.assertAlmostRelativeEqual(kinetic_energy + potential_energy, -0.25 | nbody_system.energy, 3)
self.assertAlmostRelativeEqual(instance.total_mass, 1.0 | nbody_system.mass, 3)
self.assertAlmostRelativeEqual(instance.center_of_mass_position, [1.4, 2.5, 3.6] | nbody_system.length, 3)
self.assertAlmostRelativeEqual(instance.center_of_mass_velocity, [4, 5, 6] | nbody_system.speed, 3)
instance.cleanup_code()
instance.stop()
def test26(self):
particles = datamodel.Particles(
mass=[1, 2] | nbody_system.mass,
x=[-1, 1] | nbody_system.length,
y=[0, 0] | nbody_system.length,
z=[0, 0] | nbody_system.length,
vx=[-1, 1] | nbody_system.speed,
vy=[-1, 1] | nbody_system.speed,
vz=[-1, 1] | nbody_system.speed,
id=[3, 4],
)
instance = ph4()
instance.particles.add_particles(particles)
self.assertEquals(instance.particles.index_in_code, [3, 4])
instance.commit_particles()
print instance.particles[0].potential_in_code
self.assertEquals(
instance.particles[0].potential(G=nbody_system.G),
-(nbody_system.G * (2 | nbody_system.mass)) / (2 | nbody_system.length),
)
self.assertEquals(
instance.particles[0].potential_in_code,
-(nbody_system.G * (2 | nbody_system.mass)) / (2 | nbody_system.length),
)
def test23(self):
particles = datamodel.Particles(
mass=[1, 2] | nbody_system.mass,
x=[-1, 1] | nbody_system.length,
y=[-1, 1] | nbody_system.length,
z=[-1, 1] | nbody_system.length,
vx=[-1, 1] | nbody_system.speed,
vy=[-1, 1] | nbody_system.speed,
vz=[-1, 1] | nbody_system.speed,
)
instance = ph4()
overlay = datamodel.ParticlesOverlay(instance.particles)
overlay.add_particles(particles)
all_attributes = overlay.get_values_in_store(
overlay.get_all_indices_in_store(), ["mass", "x", "y", "z", "vx", "vy", "vz"]
)
self.assertEquals(all_attributes[0], [1, 2] | nbody_system.mass)
self.assertEquals(instance.particles.mass, [1, 2] | nbody_system.mass)
self.assertEquals(overlay.mass, [1, 2] | nbody_system.mass)
self.assertEquals(overlay.position, [[-1.0, -1.0, -1.0], [1.0, 1.0, 1.0]] | nbody_system.length)
def test10(self):
instance = ph4()
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | nbody_system.length ** 2
instance.parameters.timestep_parameter = 0.01
stars = new_plummer_model(100)
instance.particles.add_particles(stars)
channel = stars.new_channel_to(instance.particles)
instance.evolve_model(0.001 | nbody_system.time)
e0 = instance.kinetic_energy + instance.potential_energy
stars.mass *= 0.9
channel.copy()
instance.synchronize_model()
e1 = instance.kinetic_energy + instance.potential_energy
instance.cleanup_code()
instance.stop()
delta_e = e1 - e0
self.assertTrue(e1 != e0)
def test4(self):
instance = ph4()
instance.initialize_code()
particles = datamodel.Particles(6)
particles.mass = nbody_system.mass.new_quantity(range(1, 7))
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()
copyof = instance.particles.copy()
instance.cleanup_code()
instance.stop()
self.assertEquals(2 | nbody_system.mass, copyof[1].mass)
def test11(self):
print "Testing PH4 collision_detection"
particles = datamodel.Particles(7)
particles.mass = 0.000001 | 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 = ph4()
instance.initialize_code()
instance.parameters.set_defaults()
instance.parameters.epsilon_squared = 0 | nbody_system.length ** 2
instance.particles.add_particles(particles)
collisions = instance.stopping_conditions.collision_detection
collisions.enable()
for i in range(3): # PH4 can handle only one collision (=closest) at a time
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)), 1)
self.assertEquals(len(collisions.particles(0)), 1)
self.assertEquals(len(instance.particles - collisions.particles(0) - collisions.particles(1)), 5 - i)
self.assertEquals(
abs(collisions.particles(0).x - collisions.particles(1).x)
< (collisions.particles(0).radius + collisions.particles(1).radius),
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 integrate_system(N, t_end, seed=None):
gravity = ph4()
gravity.initialize_code()
gravity.parameters.set_defaults()
if seed is not None: numpy.random.seed(seed)
stars = new_plummer_model(N)
stars.mass = 1./N | nbody_system.mass
stars.scale_to_standard(smoothing_length_squared
= gravity.parameters.epsilon_squared)
id = numpy.arange(N)
stars.id = id+1
# Set dynamical radii for encounters.
stars.radius = 0.5*stars.mass.number | nbody_system.length
gravity.particles.add_particles(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
init_smalln()
kep = Kepler(unit_converter=None)
kep.initialize_code()
multiples_code = multiples.Multiples(gravity, new_smalln, kep)
multiples_code.neighbor_perturbation_limit = 0.05
multiples_code.global_debug = 1
# global_debug = 0: no output from multiples
# 1: minimal output
# 2: debugging output
# 3: even more output
print ''
print 'multiples_code.neighbor_veto =', \
multiples_code.neighbor_veto
print 'multiples_code.neighbor_perturbation_limit =', \
multiples_code.neighbor_perturbation_limit
print 'multiples_code.retain_binary_apocenter =', \
multiples_code.retain_binary_apocenter
print 'multiples_code.wide_perturbation_limit =', \
multiples_code.wide_perturbation_limit
# Advance the system.
E0 = print_diagnostics(multiples_code)
multiples_code.evolve_model(t_end)
print_diagnostics(multiples_code, E0)
gravity.stop()
kep.stop()
stop_smalln()
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 test21(self):
particles = new_plummer_model(200)
particles.scale_to_standard()
instance = ph4()
instance.initialize_code()
instance.parameters.epsilon_squared = 0.00000 | nbody_system.length ** 2
instance.particles.add_particles(particles)
x = numpy.arange(-1, 1, 0.1) | nbody_system.length
zero = numpy.zeros(len(x)) | nbody_system.length
potential0 = instance.get_potential_at_point(zero, x, zero, zero)
instance.stop()
for n in (2, 3, 4):
instance = ph4(number_of_workers=n)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.00000 | nbody_system.length ** 2
instance.particles.add_particles(particles)
potential = instance.get_potential_at_point(zero, x, zero, zero)
self.assertAlmostRelativeEquals(potential0, potential, 8)
instance.stop()
def run_pyth(te=100):
dt = 0.01 | nbody_system.time
t_end = te | nbody_system.time
code = ph4()
code.parameters.timestep_parameter = dt.value_in(nbody_system.time)
code.particles.add_particles(new_particles())
x = AdaptingVectorQuantity()
y = AdaptingVectorQuantity()
t = 0. | nbody_system.time
eccents_12 = []
eccents_23 = []
eccents_31 = []
semmajaxs_12 = []
semmajaxs_23 = []
semmajaxs_31 = []
times = []
while(t < t_end-dt/2):
t=t+dt
code.evolve_model(t)
x.append(code.particles.x)
y.append(code.particles.y)
mass1, mass2, semimajor_axis_12, eccentricity_12, true_anomaly, inclination, long_asc_node, arg_per = orbital_elements_from_binary([code.particles[0], code.particles[1]])
mass2, mass3, semimajor_axis_23, eccentricity_23, true_anomaly, inclination, long_asc_node, arg_per = orbital_elements_from_binary([code.particles[1], code.particles[2]])
mass3, mass1, semimajor_axis_31, eccentricity_31, true_anomaly, inclination, long_asc_node, arg_per = orbital_elements_from_binary([code.particles[2], code.particles[0]])
eccents_12.append(eccentricity_12)
eccents_23.append(eccentricity_23)
eccents_31.append(eccentricity_31)
semmajaxs_12.append(semimajor_axis_12.value_in(nbody_system.length))
semmajaxs_23.append(semimajor_axis_23.value_in(nbody_system.length))
semmajaxs_31.append(semimajor_axis_31.value_in(nbody_system.length))
times.append(t.value_in(nbody_system.time))
code.stop()
return x,y,times,semmajaxs_12,semmajaxs_23,semmajaxs_31,eccents_12,eccents_23,eccents_31
def test5(self):
instance = ph4()
instance.initialize_code()
instance.parameters.manage_encounters = 2
instance.parameters.epsilon_squared = 0.0 | nbody_system.length ** 2
particles = datamodel.Particles(6)
particles.mass = [0.01, 0.1, 0.1, 0.1, 0.1, 0.1] | nbody_system.mass
particles.radius = 0.1 | nbody_system.length
particles.position = [
[-1.0, 0.0, 0.0], # first two close together
[-1.2, 0.0, 0.0],
[0.0, 4.0, 0.0], # rest far away
[0.0, 5.0, 0.0],
[0.0, 6.0, 0.0],
[0.0, 7.0, 0.0],
] | 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()
instance.evolve_model(0.1 | nbody_system.time)
instance.update_particle_set()
self.assertEquals(len(instance.particles), 5)
self.assertEquals(instance.particles.index_in_code, [3, 4, 5, 6, 10])
self.assertEquals(instance.particles.mass, [0.1, 0.1, 0.1, 0.1, 0.11] | nbody_system.mass)
self.assertEquals(len(particles), 6)
instance.particles.synchronize_to(particles)
self.assertEquals(len(particles), 5)
self.assertEquals(particles.mass, [0.1, 0.1, 0.1, 0.1, 0.11] | nbody_system.mass)
binary_energy1, error = instance.legacy_interface.get_binary_energy()
self.assertEquals(error, 0)
self.assertTrue(binary_energy1 < 0)
binary_energy2 = instance.get_binary_energy()
instance.cleanup_code()
instance.stop()
self.assertEquals(binary_energy2.value_in(nbody_system.energy), binary_energy1)
def test15(self):
instance = ph4()
instance.initialize_code()
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)
mass = instance.particles[0].mass
instance.cleanup_code()
instance.stop()
self.assertEquals(mass, 1.0 | nbody_system.mass)
def test17(self):
print "Testing parameter defaults"
instance = ph4()
instance.parameters.epsilon_squared = 0.5 | nbody_system.length * nbody_system.length
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)
self.assertAlmostRelativeEquals(
instance.parameters.epsilon_squared, 0.5 | nbody_system.length * nbody_system.length
)
self.assertAlmostRelativeEquals(instance.parameters.timestep_parameter, 0.14)
self.assertAlmostRelativeEquals(instance.parameters.use_gpu, 0)
self.assertAlmostRelativeEquals(instance.parameters.manage_encounters, 4)
def test28(self):
particles = datamodel.Particles(
mass=[1, 2] | nbody_system.mass,
x=[-2, 2] | nbody_system.length,
y=[0, 0] | nbody_system.length,
z=[0, 0] | nbody_system.length,
vx=[-1, 1] | nbody_system.speed,
vy=[-1, 1] | nbody_system.speed,
vz=[-1, 1] | nbody_system.speed,
)
instance = ph4()
instance.particles.add_particles(particles)
instance.evolve_model(0.1 | nbody_system.time)
self.assertEquals(len(instance.particles), 2)
instance.particles.remove_particle(particles[0])
instance.evolve_model(0.2 | nbody_system.time)
self.assertEquals(len(instance.particles), 1)
def test2(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = ph4(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | units.AU ** 2
instance.parameters.timestep_parameter = 0.01
instance.dt_dia = 5000
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
instance.particles.add_particles(stars)
instance.commit_particles()
for x in range(1, 365, 30):
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, "ph4-earth-sun2.svg")
figure.savefig(output_file)
instance.cleanup_code()
instance.stop()
def test20(self):
instance = ph4()
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, 6)
self.assertAlmostEqual(fy, 0.0 | nbody_system.acceleration, 6)
self.assertAlmostEqual(fz, 0.0 | nbody_system.acceleration, 6)
potentials = [-4.57110767688, -2.66662518639, -2.13331892165] | nbody_system.length ** 2 / (
nbody_system.time ** 2
)
for x, pot in zip((0.25, 0.5, 0.75), potentials):
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.assertAlmostRelativeEquals(fy0, 0.0 | nbody_system.acceleration, 6)
self.assertAlmostRelativeEquals(fz0, 0.0 | nbody_system.acceleration, 6)
self.assertAlmostRelativeEquals(fy1, 0.0 | nbody_system.acceleration, 6)
self.assertAlmostRelativeEquals(fz1, 0.0 | nbody_system.acceleration, 6)
self.assertAlmostRelativeEquals(fx0, -1.0 * fx1, 5)
fx = (-1.0 / (x0 ** 2) + 1.0 / (x1 ** 2)) * (1.0 | nbody_system.length ** 3 / nbody_system.time ** 2)
print fx, fx0
self.assertAlmostRelativeEquals(fx, fx0, 2)
self.assertAlmostRelativeEquals(potential0, potential1, 5)
self.assertAlmostRelativeEquals(potential0, pot, 5)
instance.stop()
def test6(self):
instance = ph4()
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | 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)
instance.commit_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.stop()
def xtest13(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 = ph4()
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 test1(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = ph4(convert_nbody) # , redirection="none")#, debugger="xterm")
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | units.AU ** 2
instance.parameters.timestep_parameter = 0.01
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
instance.particles.add_particles(stars)
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 test24(self):
particles = datamodel.Particles(
mass=[1, 2] | nbody_system.mass,
x=[-1, 1] | nbody_system.length,
y=[-1, 1] | nbody_system.length,
z=[-1, 1] | nbody_system.length,
vx=[-1, 1] | nbody_system.speed,
vy=[-1, 1] | nbody_system.speed,
vz=[-1, 1] | nbody_system.speed,
)
instance = ph4()
instance.particles.add_particles(particles)
self.assertEquals(len(instance.particles), 2)
self.assertAlmostRelativeEquals(instance.particles.mass, [1, 2] | nbody_system.mass)
instance.cleanup_code()
instance.initialize_code()
instance.particles.add_particles(particles)
self.assertEquals(len(instance.particles), 2)
self.assertAlmostRelativeEquals(instance.particles.mass, [1, 2] | nbody_system.mass)
def test25(self):
particles = datamodel.Particles(
mass=[1, 2] | nbody_system.mass,
x=[-1, 1] | nbody_system.length,
y=[-1, 1] | nbody_system.length,
z=[-1, 1] | nbody_system.length,
vx=[-1, 1] | nbody_system.speed,
vy=[-1, 1] | nbody_system.speed,
vz=[-1, 1] | nbody_system.speed,
id=[3, 4],
)
instance = ph4()
instance.particles.add_particles(particles)
self.assertEquals(instance.particles.index_in_code, [3, 4])
instance.commit_particles()
instance.particles.remove_particle(particles[1])
instance.recommit_particles()
self.assertEquals(instance.particles.index_in_code, [3])
instance.particles.add_particle(particles[1])
instance.recommit_particles()
self.assertEquals(instance.particles.index_in_code, [3, 4])
def test25(self):
particles = datamodel.Particles(
mass=[1,2] | nbody_system.mass,
x=[-1,1] | nbody_system.length,
y=[-1,1] | nbody_system.length,
z=[-1,1] | nbody_system.length,
vx=[-1,1] | nbody_system.speed,
vy=[-1,1] | nbody_system.speed,
vz=[-1,1] | nbody_system.speed,
id=[3,4]
)
instance=ph4()
instance.particles.add_particles(particles)
self.assertEqual(instance.particles.index_in_code, [3,4])
instance.commit_particles()
instance.particles.remove_particle(particles[1])
instance.recommit_particles()
self.assertEqual(instance.particles.index_in_code, [3])
instance.particles.add_particle(particles[1])
instance.recommit_particles()
self.assertEqual(instance.particles.index_in_code, [3,4])
def test24(self):
particles = datamodel.Particles(
mass=[1,2] | nbody_system.mass,
x=[-1,1] | nbody_system.length,
y=[-1,1] | nbody_system.length,
z=[-1,1] | nbody_system.length,
vx=[-1,1] | nbody_system.speed,
vy=[-1,1] | nbody_system.speed,
vz=[-1,1] | nbody_system.speed
)
instance=ph4()
instance.particles.add_particles(particles)
self.assertEqual(len(instance.particles), 2)
self.assertAlmostRelativeEquals(instance.particles.mass, [1,2] | nbody_system.mass)
instance.cleanup_code()
instance.initialize_code()
instance.particles.add_particles(particles)
self.assertEqual(len(instance.particles), 2)
self.assertAlmostRelativeEquals(instance.particles.mass, [1,2] | nbody_system.mass)
def xtest7(self):
instance = ph4()
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | nbody_system.length**2
instance.set_eta(0.01,0.02)
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)
instance.initialize_particles(0.0 )
zero = [0.0, 0.0, 0.0] | nbody_system.length
fx, fy, fz = instance.get_gravity_at_point(zero, [0.5, 1.0, 1.5] | nbody_system.length, zero, zero)
self.assertAlmostRelativeEqual(fx[0], -3.55555555556 | nbody_system.acceleration, 5)
self.assertAlmostRelativeEqual(fy[0], 0.0 | nbody_system.acceleration, 3)
self.assertAlmostRelativeEqual(fz[0], 0.0 | nbody_system.acceleration, 3)
self.assertAlmostRelativeEqual(fx[1], 0.0 | nbody_system.acceleration, 3)
self.assertAlmostRelativeEqual(fy[1], 0.0 | nbody_system.acceleration, 3)
self.assertAlmostRelativeEqual(fz[1], 0.0 | nbody_system.acceleration, 3)
self.assertAlmostRelativeEqual(fx[2], 3.55555555556 | nbody_system.acceleration, 5)
self.assertAlmostRelativeEqual(fy[2], 0.0 | nbody_system.acceleration, 3)
self.assertAlmostRelativeEqual(fz[2], 0.0 | nbody_system.acceleration, 3)
n = 512
x = nbody_system.length.new_quantity(numpy.linspace(0.1, 1.9, n))
zero = nbody_system.length.new_quantity(numpy.zeros(n))
fx, fy, fz = instance.get_gravity_at_point(zero, x, zero, zero)
for i in range(n/2):
self.assertAlmostRelativeEqual(fx[i], - fx[n - 1 - i], 5)
instance.stop()
def test23(self):
particles = datamodel.Particles(
mass=[1,2] | nbody_system.mass,
x=[-1,1] | nbody_system.length,
y=[-1,1] | nbody_system.length,
z=[-1,1] | nbody_system.length,
vx=[-1,1] | nbody_system.speed,
vy=[-1,1] | nbody_system.speed,
vz=[-1,1] | nbody_system.speed
)
instance=ph4()
overlay = datamodel.ParticlesOverlay(instance.particles)
overlay.add_particles(particles)
all_attributes = overlay.get_values_in_store(overlay.get_all_indices_in_store(), ['mass', 'x', 'y', 'z', 'vx', 'vy', 'vz'])
self.assertEqual(all_attributes[0], [1,2] | nbody_system.mass )
self.assertEqual(instance.particles.mass, [1,2] | nbody_system.mass )
self.assertEqual(overlay.mass, [1,2] | nbody_system.mass )
self.assertEqual(overlay.position, [[-1., -1., -1.], [ 1., 1., 1.]] | nbody_system.length )
def test0(self):
instance = ph4()
instance.stop()
def new_star_code_ph4(self):
result = ph4(mode="gpu")
result.parameters.epsilon_squared = self.star_epsilon**2
result.particles.add_particles(self.new_particles_cluster())
result.commit_particles()
return result
def new_ph4():
code = ph4()
code.initialize_code()
code.parameters.set_defaults()
return code
def evolve_cluster(cluster,mCut,dt,tend,mCluster,rCluster):
print 'Start evolving the cluster with mCut =', mCut
# timing
t1 = time()
converter=nbody_system.nbody_to_si(mCluster,rCluster)
# split 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"])
print 'Number of low-mass stars:', low_mass_stars.__len__()
print 'Number of high-mass stars:', high_mass_stars.__len__()
# make 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)
# make bridge
combined_gravity = bridge()
combined_gravity.add_system(code_tree,(code_direct,))
combined_gravity.add_system(code_direct,(code_tree,))
combined_gravity.timestep = dt
# the initial total energy
E0 = combined_gravity.potential_energy + combined_gravity.kinetic_energy
# evolve the model
times = quantities.arange(0.|units.Myr, tend+dt, dt)
n_step = len(times)
dE = np.empty(n_step)
Qs = np.empty(n_step)
for i,t in enumerate(times):
if t.value_in(units.Myr)%1 == 0:
print "Time =", t.in_(units.Myr)
channel_from_code_tree.copy()
channel_from_code_direct.copy()
combined_gravity.evolve_model(t, timestep=dt)
U = cluster.potential_energy()
T = cluster.kinetic_energy()
Et = U + T
dE[i] = np.abs((E0-Et)/E0)
Qs[i] = -T / U
code_tree.stop()
code_direct.stop()
t2 = time()
print 'Finished. Time cost: %.2f s'%(t2-t1)
output_filename = 'ee_q_%.1f.txt'%mCut.value_in(units.MSun)
with open(output_filename, 'w'):
np.savetxt(output_filename, np.append(dE,Qs).reshape(2,n_step).transpose())
print 'Saved the data of energy error and virial ratios in', output_filename
# plot energy
plot_energy_error(times.value_in(units.Myr), dE, Qs, mCut)
return dE[-1], Qs[-1], t2-t1
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 test4(self):
instance = ph4()
self._run_addition_removal_test(instance)
if not read_from_file:
write.write_initial_state(MasterSet, initial_conditions, cluster_name)
# Define PH4-Related Initial Conditions
time = 0.0 | units.Myr
delta_t = 0.002 | units.Myr
number_of_steps = options.num_steps
end_time = number_of_steps*delta_t
num_workers = 1
eps2 = 1 | units.AU**2
use_gpu = options.use_gpu
gpu_ID = options.gpu_ID
# Setting PH4 as the Top-Level Gravity Code
if use_gpu == 1:
gravity = ph4(number_of_workers = num_workers, redirection = "none", mode = "gpu",
convert_nbody=LargeScaleConverter)
else:
gravity = ph4(number_of_workers = num_workers, redirection = "none",
convert_nbody=LargeScaleConverter)
# Initializing PH4 with Initial Conditions
gravity.initialize_code()
gravity.parameters.set_defaults()
gravity.parameters.begin_time = time
gravity.parameters.epsilon_squared = eps2
gravity.parameters.timestSep_parameter = options.dt
# Setting up the Code to Run with GPUs Provided by Command Line
gravity.parameters.use_gpu = use_gpu
gravity.parameters.gpu_id = gpu_ID
def get_ph4(converter):
instance = ph4(converter)
instance.initialize_code()
instance.parameters.set_defaults()
return instance
t_end = t_end | nbody_system.time
dt = t_end / float(nsteps)
bodies = new_plummer_model(N)
masses = new_powerlaw_mass_distribution(N,
mass_min=0.1 | units.MSun,
mass_max=10 | units.MSun,
alpha=-2.35)
masses /= masses.sum()
bodies.mass = masses | nbody_system.mass
bodies.radius = 0.001 | nbody_system.length
Mtot_init = 1 | nbody_system.mass
gravity = ph4(number_of_workers=4)
gravity.particles.add_particles(bodies)
bodies.scale_to_standard(virial_ratio=Qvir)
channel_from_gd_to_framework = gravity.particles.new_channel_to(bodies)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
Etot_init = gravity.kinetic_energy + gravity.potential_energy
Etot_prev = Etot_init
time = 0.0 | t_end.unit
Nenc = 0
dEk_enc = zero
dEp_enc = zero
print MasterSet
time = 0.0 | nbody_system.time
delta_t = 0.05 | nbody_system.time
number_of_steps = 10
end_time = number_of_steps * delta_t
num_workers = 1
eps2 = 0.0 | nbody_system.length**2
use_gpu = 1
gpu_ID = -1
# Setting PH4 as the Top-Level Gravity Code
if use_gpu == 1:
gravity = ph4(number_of_workers=num_workers,
redirection="none",
mode="gpu")
#try:
#gravity = ph4(number_of_workers = num_workers, redirection = "none", mode = "gp$
#except Exception as ex:
# gravity = ph4(number_of_workers = num_workers, redirection = "none")
# print "*** GPU worker code not found. Reverting to non-GPU code. ***"
else:
gravity = grav(number_of_workers=num_workers, redirection="none")
# Initializing PH4 with Initial Conditions
gravity.initialize_code()
gravity.parameters.set_defaults()
gravity.parameters.begin_time = time
gravity.parameters.epsilon_squared = eps2
gravity.parameters.timestep_parameter = delta_t.number
def integrate_system(N, t_end, seed=None):
total_mass = N | units.MSun
length = 1 | units.parsec
converter = nbody_system.nbody_to_si(total_mass, length)
gravity = ph4(convert_nbody=converter)
gravity.initialize_code()
gravity.parameters.set_defaults()
gravity.parameters.epsilon_squared = (0.0 | units.parsec)**2
if seed is not None: numpy.random.seed(seed)
stars = new_plummer_model(N, convert_nbody=converter)
stars.mass = total_mass / N
stars.scale_to_standard(
convert_nbody=converter,
smoothing_length_squared=gravity.parameters.epsilon_squared)
id = numpy.arange(N)
stars.id = id + 1
stars.radius = 0.5 / N | units.parsec
gravity.particles.add_particles(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
init_smalln(converter)
kep = Kepler(unit_converter=converter)
kep.initialize_code()
multiples_code = multiples.Multiples(gravity, new_smalln, kep, constants.G)
multiples_code.neighbor_perturbation_limit = 0.05
multiples_code.global_debug = 1
###BOOKLISTSTOP2###
# global_debug = 0: no output from multiples
# 1: minimal output
# 2: debugging output
# 3: even more output
print ''
print 'multiples_code.neighbor_veto =', \
multiples_code.neighbor_veto
print 'multiples_code.neighbor_perturbation_limit =', \
multiples_code.neighbor_perturbation_limit
print 'multiples_code.retain_binary_apocenter =', \
multiples_code.retain_binary_apocenter
print 'multiples_code.wide_perturbation_limit =', \
multiples_code.wide_perturbation_limit
time = numpy.sqrt(length**3 / (constants.G * total_mass))
print '\ntime unit =', time.in_(units.Myr)
###BOOKLISTSTART3###
E0 = print_diagnostics(multiples_code)
multiples_code.evolve_model(t_end)
print_diagnostics(multiples_code, E0)
###BOOKLISTSTOP3###
gravity.stop()
kep.stop()
stop_smalln()
particles[i].velocity = [
math.sin(angle) * vel + VelocityMilky[0],
-math.cos(angle) * vel + VelocityMilky[1], VelocityMilky[2]
]
i += 1
return particles
Tracker = Nstars()
print(Tracker)
# In[5]:
#This ph4 will be replaced by the Fi later
converter = nbody_system.nbody_to_si(1.0e12 | units.MSun, 100 | units.kpc)
gravity = ph4(converter)
gravity.particles.add_particles(Galaxies)
channel1 = gravity.particles.new_channel_to(Galaxies)
channel2 = Tracker.new_channel_to(Tracker)
DeltaT = 0.1 #This is the timestep we will use in Myr
#If we want to have a non constant DeltaT we would need to change some of the code since leap-frog is not stable
#enough for varying timesteps. Can be done by finishing the leap-frog and starting a new one
gravity.timestep = DeltaT | units.Myr
times = numpy.arange(0., 50, DeltaT) | units.Myr
unity = 1 | units.m**-1 * units.s**2 #We do this to remove the units inside the vector
unity2 = 1 | units.m * units.s**-2 #Here we add the units on the outside
Accelout = [0, 0, 0]
#Now that we have initialised our particle set we have the main gravitational solver with a certain timestep DeltaT
#This is what will later be the main solving part of Fi.
def integrate_system(N, t_end, seed=None):
# Initialize an N-body module and load a stellar system.
mass = N | units.MSun
length = 1 | units.parsec
converter = nbody_system.nbody_to_si(mass, length)
gravity = ph4(convert_nbody=converter)
gravity.initialize_code()
gravity.parameters.set_defaults()
gravity.parameters.epsilon_squared = (0.0 | units.parsec)**2
if seed is not None: numpy.random.seed(seed)
stars = new_plummer_model(N, convert_nbody=converter)
stars.mass = mass / N
stars.scale_to_standard(
convert_nbody=converter,
smoothing_length_squared=gravity.parameters.epsilon_squared)
# Star IDs are important, as they are used in multiples bookkeeping.
id = numpy.arange(N)
stars.id = id + 1
# Set dynamical radii.
#stars.radius = 0.5/N | units.parsec
stars.radius = 2000 | units.AU
gravity.particles.add_particles(stars)
# Add Planets
do_planets = True
if do_planets:
systems_SI = create.planetary_systems(stars,
N - 1,
'test_planets',
Jupiter=True)
gravity.particles.add_particles(systems_SI)
# Enable collision detection.
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
SmallScaleConverter = nbody_system.nbody_to_si(2 * mass / N,
4000 | units.AU)
# Define the small-N code.
init_smalln(SmallScaleConverter)
# Define a Kepler module.
kep = Kepler(unit_converter=SmallScaleConverter)
kep.initialize_code()
# Create the multiples module.
global multiples_code
multiples_code = multiples2.Multiples(gravity, new_smalln, kep,
constants.G)
multiples_code.neighbor_perturbation_limit = 0.05
multiples_code.neighbor_veto = True
multiples_code.global_debug = 1 # 0: no output from multiples
# 1: minimal output
# 2: debugging output
# 3: even more output
# Setting Up the Encounter Handler
encounters = EncounterHandler()
multiples_code.callback = encounters.handle_encounter_v3
# Print selected multiples settings.
print ''
print 'multiples_code.neighbor_veto =', \
multiples_code.neighbor_veto
print 'multiples_code.neighbor_perturbation_limit =', \
multiples_code.neighbor_perturbation_limit
print 'multiples_code.retain_binary_apocenter =', \
multiples_code.retain_binary_apocenter
print 'multiples_code.wide_perturbation_limit =', \
multiples_code.wide_perturbation_limit
# Advance the system.
time = numpy.sqrt(length**3 / (constants.G * mass))
print '\ntime unit =', time.in_(units.Myr)
E0 = print_diagnostics(multiples_code)
dt = 0.1 | units.Myr
t_current = 0.0 | units.Myr
#gravity.particles[-1].mass += 1 | units.MSun
while t_current <= t_end:
t_current += dt
multiples_code.evolve_model(t_current)
print gravity.particles.index_in_code #, gravity.particles[0].x
#print multiples_code.particles[-1].key, multiples_code.particles[-1].x
print multiples_code._inmemory_particles.id, #multiples_code._inmemory_particles[-1].x
#print stars[0].id
# Testing the Multiples & Gravity Particle Set Differences
#test_psystem_id = systems_SI[0].host_star
#test_psystem_hs_grav = [star.x for star in gravity.particles if star.index_in_code == test_psystem_id]
#test_psystem_hs_mult = [star.x for star in multiples_code.particles if star.idex_in_code == test_psystem_id]
#print "-----------------------------"
#print "X Position in PH4", test_pystem_hs_grav.in_(units.parsec)
#print "X Position in Multiples", test_psystem_hs_mult.in_(units.parsec)
#print "Difference in Particle Sets", test_pystem_hs_grav.in_(units.parsec) - test_psystem_hs_mult.in_(units.parsec)
#print "-----------------------------"
print_diagnostics(multiples_code, E0)
gravity.stop()
kep.stop()
stop_smalln()
