def evolve_model(self):
convert_nbody = nbody_system.nbody_to_si(
1.0 | units.MSun, 149.5e6 | units.km)
hermite = Hermite(convert_nbody)
hermite.initialize_code()
hermite.parameters.epsilon_squared = 0.0 | units.AU**2
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
sun = stars[0]
Earth = blender.Primitives.sphere(10, 10, 0.1) # Make the earth avatar
Sun = blender.Primitives.sphere(32, 32, 1) # Make the sun avatar
hermite.particles.add_particles(stars)
for i in range(1*365):
hermite.evolve_model(i | units.day)
hermite.particles.copy_values_of_all_attributes_to(stars)
# update avatar positions:
Earth.loc = (
1*earth.position.value_in(units.AU)[0],
1*earth.position.value_in(units.AU)[1],
earth.position.value_in(units.AU)[2])
Sun.loc = (
1*sun.position.value_in(units.AU)[0],
1*sun.position.value_in(units.AU)[1],
sun.position.value_in(units.AU)[2])
blender.Redraw()
hermite.print_refs()
hermite.stop()
def evolve_system(particles):
"""
Evolves the system using the Hermite integrator.
Parameters
----------
particles: amuse.datamodel.particles.Particles instance
"""
times = numpy.linspace(0.0001, args.time, args.steps) |u.yr
intr = Hermite(nbody_to_si(particles.total_mass(), 1 | u.AU))
intr.particles.add_particles(particles)
energy_begin = intr.get_total_energy()
if args.dt is not None:
intr.set_dt_param(args.dt)
for t in times:
intr.evolve_model(t)
energy_error = (intr.get_total_energy() - energy_begin)/energy_begin
print(intr.get_time_step().in_(u.day), intr.get_time().in_(u.yr))
print(energy_error)
print("energy error:{}".format(energy_error))
intr.stop()
def evolve_system(particles):
"""
Evolves the system using the Hermite integrator.
Parameters
----------
particles: amuse.datamodel.particles.Particles instance
"""
times = numpy.linspace(0.0001, args.time, args.steps) | u.yr
intr = Hermite(nbody_to_si(particles.total_mass(), 1 | u.AU))
intr.particles.add_particles(particles)
energy_begin = intr.get_total_energy()
if args.dt is not None:
intr.set_dt_param(args.dt)
for t in times:
intr.evolve_model(t)
energy_error = (intr.get_total_energy() - energy_begin) / energy_begin
print(intr.get_time_step().in_(u.day), intr.get_time().in_(u.yr))
print(energy_error)
print("energy error:{}".format(energy_error))
intr.stop()
def simulate_system_until(particles, end_time):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun,
149.5e6 | units.km)
instance = Hermite(convert_nbody)
instance.parameters.epsilon_squared = 0.0 | units.AU**2
instance.particles.add_particles(particles)
t0 = 0 | units.day
dt = 10 | units.day
t = t0
earth = instance.particles[1]
x_values = quantities.AdaptingVectorQuantity()
y_values = quantities.AdaptingVectorQuantity()
while t < end_time:
instance.evolve_model(t)
x_values.append(earth.x)
y_values.append(earth.y)
t += dt
instance.stop()
return x_values, y_values
def simulate_system_until(particles, end_time):
convert_nbody = nbody_system.nbody_to_si(
1.0 | units.MSun, 149.5e6 | units.km)
instance = Hermite(convert_nbody)
instance.parameters.epsilon_squared = 0.0 | units.AU**2
instance.particles.add_particles(particles)
t0 = 0 | units.day
dt = 10 | units.day
t = t0
earth = instance.particles[1]
x_values = quantities.AdaptingVectorQuantity()
y_values = quantities.AdaptingVectorQuantity()
while t < end_time:
instance.evolve_model(t)
x_values.append(earth.x)
y_values.append(earth.y)
t += dt
instance.stop()
return x_values, y_values
def evolve_model(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun,
149.5e6 | units.km)
hermite = Hermite(convert_nbody)
hermite.initialize_code()
hermite.parameters.epsilon_squared = 0.0 | units.AU**2
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
sun = stars[0]
Earth = blender.Primitives.sphere(10, 10, 0.1) # Make the earth avatar
Sun = blender.Primitives.sphere(32, 32, 1) # Make the sun avatar
hermite.particles.add_particles(stars)
for i in range(1 * 365):
hermite.evolve_model(i | units.day)
hermite.particles.copy_values_of_all_attributes_to(stars)
# update avatar positions:
Earth.loc = (1 * earth.position.value_in(units.AU)[0],
1 * earth.position.value_in(units.AU)[1],
earth.position.value_in(units.AU)[2])
Sun.loc = (1 * sun.position.value_in(units.AU)[0],
1 * sun.position.value_in(units.AU)[1],
sun.position.value_in(units.AU)[2])
blender.Redraw()
hermite.print_refs()
hermite.stop()
def test1(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
hermite = Hermite(convert_nbody)
hermite.initialize_code()
hermite.parameters.epsilon_squared = 0.0 | units.AU**2
hermite.parameters.end_time_accuracy_factor = 0.0
hermite.dt_dia = 5000
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
hermite.particles.add_particles(stars)
hermite.evolve_model(365.0 | units.day)
hermite.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.assertAlmostRelativeEqual(position_at_start, position_after_full_rotation, 6)
hermite.evolve_model(365.0 + (365.0 / 2) | units.day)
hermite.particles.copy_values_of_all_attributes_to(stars)
position_after_half_a_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostRelativeEqual(-position_at_start, position_after_half_a_rotation, 3)
hermite.evolve_model(365.0 + (365.0 / 2) + (365.0 / 4) | units.day)
hermite.particles.copy_values_of_all_attributes_to(stars)
position_after_half_a_rotation = earth.position.value_in(units.AU)[1]
self.assertAlmostRelativeEqual(-position_at_start, position_after_half_a_rotation, 3)
hermite.cleanup_code()
hermite.stop()
def test12(self):
particles = datamodel.Particles(2)
particles.x = [0.0, 1.00] | nbody_system.length
particles.y = [0.0, 0.0] | nbody_system.length
particles.z = [0.0, 0.0] | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = [5.1, 0.0] | nbody_system.speed
particles.vy = [0.0, 0.0] | nbody_system.speed
particles.vz = [0.0, 0.0] | nbody_system.speed
particles.mass = [0.1, 0.1] | nbody_system.mass
instance = Hermite()
instance.initialize_code()
instance.parameters.stopping_conditions_out_of_box_size = .5 | nbody_system.length
self.assertEquals(
instance.parameters.stopping_conditions_out_of_box_size,
.5 | nbody_system.length)
instance.particles.add_particles(particles)
instance.stopping_conditions.out_of_box_detection.enable()
instance.evolve_model(0.1 | nbody_system.time)
self.assertTrue(
instance.stopping_conditions.out_of_box_detection.is_set())
self.assertAlmostEqual(
instance.stopping_conditions.out_of_box_detection.particles(0).x,
1.0 | nbody_system.length, 3)
instance.stop()
def test15(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 = Hermite()
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 test6(self):
print "Test6: Testing Hermite parameters"
convert_nbody = nbody_system.nbody_to_si(1.0 | units.yr, 1.0 | units.AU)
instance = Hermite(convert_nbody)
value = instance.get_eps2()
self.assertEquals(0.0 | units.AU**2 , value)
self.assertAlmostEquals(0.0 | 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 = instance.get_dt_param()
self.assertEquals(0.03 , value)
self.assertAlmostEquals(0.03 , instance.parameters.dt_param)
for x in [0.001, 0.01, 0.1]:
instance.parameters.dt_param = x
self.assertAlmostEquals(x, instance.parameters.dt_param)
value = instance.get_dt_dia()
self.assertAlmostEquals(1.0 | units.yr, 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)
value = instance.get_begin_time()
self.assertEquals(0.0| units.yr, value)
self.assertAlmostEquals(0.0 | units.yr, instance.parameters.begin_time, in_units=units.yr)
for x in [1.0, 10.0, 100.0]:
instance.parameters.begin_time = x | units.yr
self.assertAlmostEquals(x | units.yr, instance.parameters.begin_time, in_units=units.yr)
instance.stop()
def test3(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun,
149.5e6 | units.km)
instance = Hermite(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.00001 | units.AU**2
instance.dt_dia = 5000
stars = datamodel.Stars(2)
star1 = stars[0]
star2 = stars[1]
star1.mass = units.MSun(1.0)
star1.position = units.AU(numpy.array((-1.0, 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((1.0, 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)
for x in range(1, 2000, 10):
instance.evolve_model(x | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
stars.savepoint()
instance.stop()
def simulate_small_cluster(number_of_stars=1000,
end_time=40 | nbody_system.time,
number_of_workers=1):
particles = new_plummer_model(number_of_stars)
particles.scale_to_standard()
gravity = Hermite(number_of_workers=number_of_workers)
gravity.parameters.epsilon_squared = 0.15 | nbody_system.length**2
gravity.particles.add_particles(particles)
from_gravity_to_model = gravity.particles.new_channel_to(particles)
time = 0.0 * end_time
total_energy_at_t0 = gravity.kinetic_energy + gravity.potential_energy
positions_at_different_times = []
positions_at_different_times.append(particles.position)
times = []
times.append(time)
print("evolving the model until t = " + str(end_time))
while time < end_time:
time += end_time / 3.0
gravity.evolve_model(time)
from_gravity_to_model.copy()
positions_at_different_times.append(particles.position)
times.append(time)
print_log(time, gravity, particles, total_energy_at_t0)
gravity.stop()
return times, positions_at_different_times
def test13(self):
particles = plummer.new_plummer_model(31)
instance = Hermite(number_of_workers=1)#, debugger="xterm")
instance.initialize_code()
instance.parameters.epsilon_squared = 0.01 | nbody_system.length ** 2
instance.particles.add_particles(particles)
instance.evolve_model(0.1 | nbody_system.time)
instance.synchronize_model()
expected_positions = instance.particles.position
instance.stop()
positions_per_workers = []
for n in [2,3,4,5]:
instance = Hermite(number_of_workers=n)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.01 | nbody_system.length ** 2
instance.particles.add_particles(particles)
instance.evolve_model(0.1 | nbody_system.time)
instance.synchronize_model()
positions_per_workers.append(instance.particles.position)
instance.stop()
for index, n in enumerate([2,3,4,5]):
self.assertAlmostEqual(expected_positions, positions_per_workers[index], 15)
def test5(self):
convert_nbody = nbody_system.nbody_to_si(5.0 | units.kg,
10.0 | units.m)
instance = Hermite(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.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, 20.0 | units.m
], curr_state):
self.assertAlmostRelativeEquals(expected, actual)
instance.stop()
self.assertEquals(curr_state[0], 16 | units.kg, 8)
def test15(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 = Hermite()
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 test22(self):
hermite = Hermite()
hermite.parameters.epsilon_squared = 0.0 | nbody_system.length**2
particles = datamodel.Particles(2)
particles.position = ([0, 0, 0], [1, 0, 0]) | nbody_system.length
particles.velocity = ([-2, 0, 0], [2, 0, 0]) | nbody_system.speed
particles.radius = 0 | nbody_system.length
particles.mass = 0.1 | nbody_system.mass
hermite.particles.add_particles(particles)
hermite.stopping_conditions.out_of_box_detection.enable()
hermite.parameters.stopping_conditions_out_of_box_size = 2 | nbody_system.length
hermite.parameters.stopping_conditions_out_of_box_use_center_of_mass = False
hermite.evolve_model(1 | nbody_system.time)
print hermite.particles.x
print hermite.particles.key, particles[1].key
print hermite.stopping_conditions.out_of_box_detection.particles(0)
self.assertTrue(
hermite.stopping_conditions.out_of_box_detection.is_set())
self.assertEquals(
len(hermite.stopping_conditions.out_of_box_detection.particles(0)),
1)
self.assertEquals(
hermite.stopping_conditions.out_of_box_detection.particles(0)
[0].key, particles[1].key)
hermite.stop()
def test5(self):
convert_nbody = nbody_system.nbody_to_si(5.0 | units.kg, 10.0 | units.m)
instance = Hermite(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.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 ,
20.0|units.m], curr_state):
self.assertAlmostRelativeEquals(expected, actual)
instance.stop()
self.assertEquals(curr_state[0], 16|units.kg, 8)
def test4(self):
convert_nbody = nbody_system.nbody_to_si(5.0 | units.kg, 10.0 | units.m)
instance = Hermite(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.particles.mass = [17.0, 33.0] | units.kg
self.assertEquals(instance.get_mass(0), 17.0| units.kg)
self.assertEquals(instance.get_mass(1), 33.0| units.kg)
instance.stop()
def test6(self):
print "Test6: Testing Hermite parameters"
convert_nbody = nbody_system.nbody_to_si(1.0 | units.yr, 1.0 | units.AU)
instance = Hermite(convert_nbody)
value = instance.get_eps2()
self.assertEquals(0.0 | units.AU**2 , value)
self.assertAlmostEquals(0.0 | 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 = instance.get_dt_param()
self.assertEquals(0.03 , value)
self.assertAlmostEquals(0.03 , instance.parameters.dt_param)
for x in [0.001, 0.01, 0.1]:
instance.parameters.dt_param = x
self.assertAlmostEquals(x, instance.parameters.dt_param)
value = instance.get_dt_dia()
self.assertAlmostEquals(1.0 | units.yr, 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)
value = instance.get_begin_time()
self.assertEquals(0.0| units.yr, value)
self.assertAlmostEquals(0.0 | units.yr, instance.parameters.begin_time, in_units=units.yr)
for x in [1.0, 10.0, 100.0]:
instance.parameters.begin_time = x | units.yr
self.assertAlmostEquals(x | units.yr, instance.parameters.begin_time, in_units=units.yr)
instance.stop()
def test13(self):
particles = plummer.new_plummer_model(31)
instance = Hermite(number_of_workers=1) #, debugger="xterm")
instance.initialize_code()
instance.parameters.epsilon_squared = 0.01 | nbody_system.length**2
instance.particles.add_particles(particles)
instance.evolve_model(0.1 | nbody_system.time)
instance.synchronize_model()
expected_positions = instance.particles.position
instance.stop()
positions_per_workers = []
for n in [2, 3, 4, 5]:
instance = Hermite(number_of_workers=n)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.01 | nbody_system.length**2
instance.particles.add_particles(particles)
instance.evolve_model(0.1 | nbody_system.time)
instance.synchronize_model()
positions_per_workers.append(instance.particles.position)
instance.stop()
for index, n in enumerate([2, 3, 4, 5]):
self.assertAlmostEqual(expected_positions,
positions_per_workers[index], 15)
def test3(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = Hermite(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.00001 | units.AU**2
instance.dt_dia = 5000
stars = datamodel.Stars(2)
star1 = stars[0]
star2 = stars[1]
star1.mass = units.MSun(1.0)
star1.position = units.AU(numpy.array((-1.0,0.0,0.0)))
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((1.0,0.0,0.0)))
star2.velocity = units.AUd(numpy.array((0.0,0.0,0.0)))
star2.radius = units.RSun(100.0)
instance.particles.add_particles(stars)
for x in range(1,2000,10):
instance.evolve_model(x | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
stars.savepoint()
instance.stop()
def test18(self):
particles = datamodel.Particles(2)
particles.x = [0.0,1.0] | 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 = Hermite()
instance.particles.add_particles(particles)
instance.commit_particles()
self.assertEquals(instance.particles[0].radius, 0.0 | nbody_system.length)
instance.parameters.end_time_accuracy_factor = 1.0
instance.evolve_model(0.1 | nbody_system.time)
self.assertAlmostRelativeEquals(instance.model_time, 0.10563767746 |nbody_system.time, 5)
instance.parameters.end_time_accuracy_factor = -1.0
instance.evolve_model(0.3 | nbody_system.time)
self.assertAlmostRelativeEquals(instance.model_time, 0.266758127609 |nbody_system.time, 5)
instance.parameters.end_time_accuracy_factor = 0.0
instance.evolve_model(0.4 | nbody_system.time)
self.assertAlmostRelativeEquals(instance.model_time, 0.4 |nbody_system.time, 6)
instance.parameters.end_time_accuracy_factor = -0.5
instance.evolve_model(0.5 | nbody_system.time)
self.assertAlmostRelativeEquals(instance.model_time, 0.48974930698 |nbody_system.time, 6)
instance.parameters.end_time_accuracy_factor = +0.5
instance.evolve_model(0.6 | nbody_system.time)
self.assertAlmostRelativeEquals(instance.model_time, 0.6042733579 |nbody_system.time, 6)
instance.stop()
def test18(self):
particles = datamodel.Particles(2)
particles.x = [0.0,1.0] | 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 = Hermite()
instance.particles.add_particles(particles)
instance.commit_particles()
self.assertEquals(instance.particles[0].radius, 0.0 | nbody_system.length)
instance.parameters.end_time_accuracy_factor = 1.0
instance.evolve_model(0.1 | nbody_system.time)
self.assertAlmostRelativeEquals(instance.model_time, 0.10563767746 |nbody_system.time, 5)
instance.parameters.end_time_accuracy_factor = -1.0
instance.evolve_model(0.3 | nbody_system.time)
self.assertAlmostRelativeEquals(instance.model_time, 0.266758127609 |nbody_system.time, 5)
instance.parameters.end_time_accuracy_factor = 0.0
instance.evolve_model(0.4 | nbody_system.time)
self.assertAlmostRelativeEquals(instance.model_time, 0.4 |nbody_system.time, 6)
instance.parameters.end_time_accuracy_factor = -0.5
instance.evolve_model(0.5 | nbody_system.time)
self.assertAlmostRelativeEquals(instance.model_time, 0.48974930698 |nbody_system.time, 6)
instance.parameters.end_time_accuracy_factor = +0.5
instance.evolve_model(0.6 | nbody_system.time)
self.assertAlmostRelativeEquals(instance.model_time, 0.6042733579 |nbody_system.time, 6)
instance.stop()
def test24(self):
hermite = Hermite(reuse_worker = True)
channel1 = hermite.legacy_interface.channel
hermite.stop()
hermite = Hermite(reuse_worker = True)
channel2 = hermite.legacy_interface.channel
hermite.stop()
self.assertEquals(id(channel1), id(channel2))
def test8(self):
print "Testing Hermite 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 = Hermite()
instance.initialize_code()
instance.parameters.set_defaults()
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 test8(self):
print "Testing Hermite 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 = Hermite()
instance.initialize_code()
instance.parameters.set_defaults()
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 test17(self):
particles = new_plummer_model(50)
particles.scale_to_standard()
instance = Hermite()
instance.parameters.epsilon_squared = 0.22000 | nbody_system.length**2
instance.particles.add_particles(particles)
self.assertEquals(len(instance.particles), 50)
instance.reset()
self.assertAlmostRelativeEquals(instance.parameters.epsilon_squared , 0.22000 | nbody_system.length**2)
self.assertEquals(len(instance.particles), 0)
instance.particles.add_particles(particles)
self.assertEquals(len(instance.particles), 50)
instance.stop()
def test19(self):
particles = datamodel.Particles(2)
particles.x = [0.0,200.0] | 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 = Hermite()
instance.particles.add_particles(particles)
instance.commit_particles()
self.assertEquals(instance.particles[0].radius, 0.0 | nbody_system.length)
instance.parameters.end_time_accuracy_factor = 0.0
instance.evolve_model(0.1 | nbody_system.time)
self.assertAlmostRelativeEquals(instance.model_time, 0.1 |nbody_system.time, 5)
instance.stop()
def test19(self):
particles = datamodel.Particles(2)
particles.x = [0.0,200.0] | 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 = Hermite()
instance.particles.add_particles(particles)
instance.commit_particles()
self.assertEquals(instance.particles[0].radius, 0.0 | nbody_system.length)
instance.parameters.end_time_accuracy_factor = 0.0
instance.evolve_model(0.1 | nbody_system.time)
self.assertAlmostRelativeEquals(instance.model_time, 0.1 |nbody_system.time, 5)
instance.stop()
def test14(self):
instance = Hermite()
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)
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, 6)
self.assertAlmostEqual(fz0, 0.0 | nbody_system.acceleration, 6)
self.assertAlmostEqual(fy1, 0.0 | nbody_system.acceleration, 6)
self.assertAlmostEqual(fz1, 0.0 | nbody_system.acceleration, 6)
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 test7(self):
print "Test7: Testing effect of Hermite 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 = Hermite(convert_nbody)
instance.parameters.end_time_accuracy_factor = 0.0
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))
G = 6.63784e-11
cm_to_m = 1. / 100.
msun_to_g = 1.988e33
pc_to_m = 3.08567758128e16
gcm_to_msunpc = 5.03e-34 * (3.086e18)**2
def print_log(time, gravity, particles, total_energy_at_t0):
kinetic_energy = gravity.kinetic_energy
potential_energy = gravity.potential_energy
total_energy_at_this_time = kinetic_energy + potential_energy
print "time : " , time
print "energy error : " , (total_energy_at_this_time - total_energy_at_t0) / total_energy_at_t0
def simulate_small_cluster(
number_of_stars = 1000.,
end_time = 40 | nbody_system.time,
number_of_workers = 1
):
#convert_nbody = nbody_system.nbody_to_si(number_of_stars | units.MSun, 1. | units.parsec)
def test23(self):
hermite = Hermite()
hermite.parameters.epsilon_squared = 0.0 | nbody_system.length**2
particles = datamodel.Particles(1)
particles.position = ([0,0,0] )| nbody_system.length
particles.velocity = ([1,0,0] )| nbody_system.speed
particles.radius = 0| nbody_system.length
particles.mass = 0.1| nbody_system.mass
hermite.particles.add_particles(particles)
hermite.evolve_model(1 | nbody_system.time)
print hermite.particles.x
self.assertAlmostRelativeEquals(hermite.model_time, 1 | nbody_system.time)
self.assertAlmostRelativeEquals(hermite.particles[0].x, 1 | nbody_system.length)
hermite.evolve_model(1.5 | nbody_system.time)
print hermite.particles.x
self.assertAlmostRelativeEquals(hermite.model_time, 1.5 | nbody_system.time)
self.assertAlmostRelativeEquals(hermite.particles[0].x, 1.5 | nbody_system.length)
hermite.stop()
def test23(self):
hermite = Hermite()
hermite.parameters.epsilon_squared = 0.0 | nbody_system.length**2
particles = datamodel.Particles(1)
particles.position = ([0,0,0] )| nbody_system.length
particles.velocity = ([1,0,0] )| nbody_system.speed
particles.radius = 0| nbody_system.length
particles.mass = 0.1| nbody_system.mass
hermite.particles.add_particles(particles)
hermite.evolve_model(1 | nbody_system.time)
print hermite.particles.x
self.assertAlmostRelativeEquals(hermite.model_time, 1 | nbody_system.time)
self.assertAlmostRelativeEquals(hermite.particles[0].x, 1 | nbody_system.length)
hermite.evolve_model(1.5 | nbody_system.time)
print hermite.particles.x
self.assertAlmostRelativeEquals(hermite.model_time, 1.5 | nbody_system.time)
self.assertAlmostRelativeEquals(hermite.particles[0].x, 1.5 | nbody_system.length)
hermite.stop()
def test2(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = Hermite(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | units.AU**2
instance.dt_dia = 5000
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
instance.particles.add_particles(stars)
for x in range(1, 500, 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, "hermite-earth-sun2.svg")
figure.savefig(output_file)
instance.cleanup_code()
instance.stop()
def test2(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = Hermite(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | units.AU**2
instance.dt_dia = 5000
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
instance.particles.add_particles(stars)
for x in range(1, 500, 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, "hermite-earth-sun2.svg")
figure.savefig(output_file)
instance.cleanup_code()
instance.stop()
def test10(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = Hermite(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | units.AU**2
instance.parameters.stopping_conditions_number_of_steps = 10
self.assertEquals(instance.parameters.stopping_conditions_number_of_steps,10)
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
instance.particles.add_particles(stars)
instance.stopping_conditions.number_of_steps_detection.enable()
instance.evolve_model(365.0 | units.day)
self.assertTrue(instance.stopping_conditions.number_of_steps_detection.is_set())
instance.particles.copy_values_of_all_attributes_to(stars)
instance.cleanup_code()
instance.stop()
def test12(self):
particles = datamodel.Particles(2)
particles.x = [0.0,1.00] | nbody_system.length
particles.y = [0.0,0.0] | nbody_system.length
particles.z = [0.0,0.0] | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = [5.1,0.0] | nbody_system.speed
particles.vy = [0.0,0.0] | nbody_system.speed
particles.vz = [0.0,0.0]| nbody_system.speed
particles.mass = [0.1,0.1] | nbody_system.mass
instance = Hermite()
instance.initialize_code()
instance.parameters.stopping_conditions_out_of_box_size = .5 | nbody_system.length
self.assertEquals(instance.parameters.stopping_conditions_out_of_box_size, .5 | nbody_system.length)
instance.particles.add_particles(particles)
instance.stopping_conditions.out_of_box_detection.enable()
instance.evolve_model(0.1 | nbody_system.time)
self.assertTrue(instance.stopping_conditions.out_of_box_detection.is_set())
self.assertAlmostEqual(instance.stopping_conditions.out_of_box_detection.particles(0).x, 1.0 |nbody_system.length, 3)
instance.stop()
def test10(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = Hermite(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | units.AU**2
instance.parameters.stopping_conditions_number_of_steps = 10
self.assertEquals(instance.parameters.stopping_conditions_number_of_steps,10)
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
instance.particles.add_particles(stars)
instance.stopping_conditions.number_of_steps_detection.enable()
instance.evolve_model(365.0 | units.day)
self.assertTrue(instance.stopping_conditions.number_of_steps_detection.is_set())
instance.particles.copy_values_of_all_attributes_to(stars)
instance.cleanup_code()
instance.stop()
def test11(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 = Hermite()
instance.initialize_code()
instance.parameters.stopping_conditions_number_of_steps = 2
self.assertEquals(instance.parameters.stopping_conditions_number_of_steps, 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 test11(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 = Hermite()
instance.initialize_code()
instance.parameters.stopping_conditions_number_of_steps = 2
self.assertEquals(instance.parameters.stopping_conditions_number_of_steps, 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 test16(self):
particles = new_plummer_model(200)
particles.scale_to_standard()
instance = Hermite()
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 = Hermite(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 test16(self):
particles = new_plummer_model(200)
particles.scale_to_standard()
instance = Hermite()
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 = Hermite(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 test22(self):
hermite = Hermite()
hermite.parameters.epsilon_squared = 0.0 | nbody_system.length**2
particles = datamodel.Particles(2)
particles.position = ([0,0,0], [1,0,0] )| nbody_system.length
particles.velocity = ([-2,0,0], [2,0,0] )| nbody_system.speed
particles.radius = 0| nbody_system.length
particles.mass = 0.1| nbody_system.mass
hermite.particles.add_particles(particles)
hermite.stopping_conditions.out_of_box_detection.enable()
hermite.parameters.stopping_conditions_out_of_box_size = 2 | nbody_system.length
hermite.parameters.stopping_conditions_out_of_box_use_center_of_mass = False
hermite.evolve_model(1 | nbody_system.time)
print hermite.particles.x
print hermite.particles.key, particles[1].key
print hermite.stopping_conditions.out_of_box_detection.particles(0)
self.assertTrue(hermite.stopping_conditions.out_of_box_detection.is_set())
self.assertEquals(len(hermite.stopping_conditions.out_of_box_detection.particles(0)), 1)
self.assertEquals(hermite.stopping_conditions.out_of_box_detection.particles(0)[0].key, particles[1].key)
hermite.stop()
def evolve_system_with_massloss(particles, mass_sequence, time_sequence,
datahandler):
"""
Parameters
----------
particles: a two-body system
mass_sequence: sequence of masses
time_sequence: sequence of times
datahandler: HDF5HandlerAmuse context manager
"""
h = datahandler
intr = Hermite(nbody_to_si(particles.total_mass(), 1 | u.AU))
intr.particles.add_particles(particles)
h.append(particles[0].period0, "period0")
for mass, time in zip(mass_sequence, time_sequence):
intr.particles.move_to_center()
intr.evolve_model(time)
intr.particles[0].mass = mass
h.append(intr.particles.center_of_mass(), "CM_position")
h.append(intr.particles.center_of_mass_velocity(), "CM_velocity")
h.append(intr.particles.position, "position")
h.append(intr.particles.velocity, "velocity")
h.append(intr.particles.mass, "mass")
h.append(intr.particles.kinetic_energy(), "kinetic_energy")
h.append(intr.particles.potential_energy(), "potential_energy")
h.append(intr.get_total_energy(), "total_energy")
h.append(time, "time")
h.append(semimajoraxis_from_binary(intr.particles), "sma")
h.append(eccentricity_from_binary(intr.particles), "eccentricity")
intr.stop()
def simulate_small_cluster(
number_of_stars=1000,
end_time=40 | nbody_system.time,
number_of_workers=1
):
particles = new_plummer_model(number_of_stars)
particles.scale_to_standard()
gravity = Hermite(number_of_workers=number_of_workers)
gravity.parameters.epsilon_squared = 0.15 | nbody_system.length ** 2
gravity.particles.add_particles(particles)
from_gravity_to_model = gravity.particles.new_channel_to(particles)
time = 0.0 * end_time
total_energy_at_t0 = gravity.kinetic_energy + gravity.potential_energy
positions_at_different_times = []
positions_at_different_times.append(particles.position)
times = []
times.append(time)
print("evolving the model until t = " + str(end_time))
while time < end_time:
time += end_time / 3.0
gravity.evolve_model(time)
from_gravity_to_model.copy()
positions_at_different_times.append(particles.position)
times.append(time)
print_log(time, gravity, particles, total_energy_at_t0)
gravity.stop()
return times, positions_at_different_times
def supernova_in_binary_nbody(M0, m0, a0, tsn):
stars = make_circular_binary(M0, m0, a0)
M, m, a, e, ta_out, inc, lan_out, aop_out = orbital_elements_from_binary(
stars, G=constants.G)
print "Initial binary: a=", a.in_(
units.AU), "e=", e, "M=", stars[0].mass, "and m=", stars[1].mass
converter = nbody_system.nbody_to_si(M+m, a)
gravity = Hermite(converter)
gravity.particles.add_particles(stars)
print "Integrate binary to t=", tsn.in_(units.day)
gravity.evolve_model(tsn)
M, m, a, e, ta_out, inc, lan_out, aop_out = orbital_elements_from_binary(
stars, G=constants.G)
print "Pre supernova orbit: a=", a.in_(units.AU), "e=", e
stars[0].mass *= 0.1
print "Reduce stellar mass to: M=", stars[0].mass, "and m=", stars[1].mass
v_kick = (0, 0, 0) | units.kms
stars[0].velocity += v_kick
gravity.evolve_model(2*tsn)
M, m, a, e, ta_out, inc, lan_out, aop_out = orbital_elements_from_binary(
stars, G=constants.G)
print "Post supernova orbit: a=", a.in_(units.AU), "e=", e
r0 = a
a_ana = post_supernova_semimajor_axis(
M0, m0, stars[0].mass, stars[1].mass, a, r0)
e_ana = post_supernova_eccentricity(
M0, m0, stars[0].mass, stars[1].mass, a, r0)
print(
"Analytic solution to post orbit orbital parameters: a=",
a_ana, "e=", e_ana,
)
gravity.stop()
def test4(self):
convert_nbody = nbody_system.nbody_to_si(5.0 | units.kg, 10.0 | units.m)
instance = Hermite(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.particles.mass = [17.0, 33.0] | units.kg
self.assertEquals(instance.get_mass(0), 17.0| units.kg)
self.assertEquals(instance.get_mass(1), 33.0| units.kg)
instance.stop()
def test20(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
hermite = Hermite(convert_nbody)
hermite.initialize_code()
hermite.parameters.epsilon_squared = 0.0 | units.AU**2
hermite.parameters.end_time_accuracy_factor = 0.0
hermite.parameters.is_time_reversed_allowed = True
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
hermite.particles.add_particles(stars)
hermite.evolve_model(365.0 | units.day)
hermite.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.assertAlmostRelativeEqual(position_at_start, position_after_full_rotation, 6)
hermite.evolve_model(365.0 - (365.0 / 2) | units.day)
hermite.particles.copy_values_of_all_attributes_to(stars)
position_after_half_a_rotation_backward = earth.position.value_in(units.AU)[0]
self.assertAlmostRelativeEqual(-position_at_start, position_after_half_a_rotation_backward, 4)
hermite.evolve_model(365.0 | units.day)
position_at_start = earth.position.value_in(units.AU)[0]
position_after_full_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostRelativeEqual(position_at_start, position_after_full_rotation, 6)
hermite.cleanup_code()
hermite.stop()
def test7(self):
print "Test7: Testing effect of Hermite 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 = Hermite(convert_nbody)
instance.parameters.end_time_accuracy_factor = 0.0
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 test14(self):
instance = Hermite()
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)
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, 6)
self.assertAlmostEqual(fz0, 0.0 | nbody_system.acceleration, 6)
self.assertAlmostEqual(fy1, 0.0 | nbody_system.acceleration, 6)
self.assertAlmostEqual(fz1, 0.0 | nbody_system.acceleration, 6)
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()
instance.commit_particles()
channelp = instance.particles.new_channel_to(particles)
start = 0 |units.yr
end = 150 | units.yr
step = 10|units.day
timerange = VectorQuantity.arange(start, end, step)
masses = []|units.MSun
for i, time in enumerate(timerange):
instance.evolve_model(time)
channelp.copy()
particles.savepoint(time)
if (i % 220 == 0):
instance.particles[0].mass = simulate_massloss(time)
masses.append(instance.particles[0].mass)
instance.stop()
particle = particles[1]
t, pos = particle.get_timeline_of_attribute_as_vector("position")
distances = pos.lengths().as_quantity_in(units.AU)
plot(timerange, distances , timerange, masses)
native_plot.show()
instance.particles.add_particles(particles)
channelp = instance.particles.new_channel_to(particles)
start = 0 |units.yr
end = 150 | units.yr
step = 10|units.day
timerange = VectorQuantity.arange(start, end, step)
masses = []|units.MSun
for i, time in enumerate(timerange):
instance.evolve_model(time)
channelp.copy()
particles.savepoint(time)
if (i % 220 == 0):
instance.particles[0].mass = simulate_massloss(time)
masses.append(instance.particles[0].mass)
instance.stop()
particle = particles[1]
t, pos = particle.get_timeline_of_attribute_as_vector("position")
distances = pos.lengths().as_quantity_in(units.AU)
plot(timerange, distances , timerange, masses)
native_plot.show()
def make_effective_iso_potential_plot(gravity):
"""
This function is copied from the amuse documentation.
The last part has been altered to also plot our Moon Earth system
and the test particles orbit.
"""
omega = (constants.G * gravity.particles.total_mass() /
(5.0 | units.AU**3)).sqrt()
center_of_mass = gravity.particles.center_of_mass()[:]
plt.rcParams.update({'font.size': 30})
figure = plt.figure(figsize=(12, 12))
ax = plt.gca()
ax.get_yaxis().get_major_formatter().set_useOffset(False)
ax.minorticks_on()
current_axes = plt.subplot(1, 1, 1)
current_axes.set_aspect("equal", adjustable="box")
lim = 6e5
potential = effective_iso_potential_plot(gravity,
omega,
xlim=[-lim, lim] | units.km,
ylim=[-lim, lim] | units.km,
center_of_rotation=center_of_mass,
fraction_screen_filled=0.85)
# Simulation towards the Moon
position = [329931, 0, 0] | units.km # position of the lagrange point
velocity = [0.14, 1.022, 0] | units.kms # these parameters worked well
gravity.particles.add_particles(create_testparticle(position, velocity))
x, y, E_begin, E_end = integrate_orbit(
1.85, gravity) # towards the moon 1.85 days is sufficent
#initialize integrator
converter = nbody_system.nbody_to_si(1.0 | units.MSun, 1.0 | units.AU)
gravity = Hermite(converter)
gravity.particles.add_particles(Earth_Moon_system())
gravity.particles.add_particles(create_testparticle(position, velocity))
gravity.particles.velocity = gravity.particles.velocity * -1.
x2, y2, E_begin2, E_end2 = integrate_orbit(
10, gravity) # towards the Earth 10 days is sufficient
# make numpy arrays
x = np.array(x)
y = np.array(y)
x2 = np.array(x2)
y2 = np.array(y2)
# Make plot
plt.scatter([0], [0], color='b', s=25, label='Earth')
plt.plot(x[1], y[1], color='r', lw=2, label='Moon')
plt.plot(x[2], y[2], color='k', lw=2, label='Test particle')
plt.plot(x2[1], y2[1], color='r', lw=2)
plt.plot(x2[2], y2[2], color='k', lw=2)
plt.legend(fontsize=12)
# Plot langrangian point
plt.scatter(329931, 0, marker='+', s=30, zorder=2, c='m')
plt.text(329931, -31306, "$L_1$", size=20, zorder=3, color='m')
# Stop integrator
gravity.cleanup_code()
gravity.stop()
# Label and show
xlabel('x')
ylabel('y')
plt.ticklabel_format(style='sci', axis='both', scilimits=(0, 0))
plt.tight_layout()
plt.savefig("lagrange_points.png")
plt.show() # show figure
def evolve_triple_with_wind(M1, M2, M3, Pora, Pin_0, ain_0, aout_0,
ein_0, eout_0, t_end, nsteps, scheme, integrator,
t_stellar, dt_se, dtse_fac, interp):
import random
from amuse.ext.solarsystem import get_position
numpy.random.seed(42)
print "Initial masses:", M1, M2, M3
triple = Particles(3)
triple[0].mass = M1
triple[1].mass = M2
triple[2].mass = M3
stellar = SeBa()
stellar.particles.add_particles(triple)
channel_from_stellar = stellar.particles.new_channel_to(triple)
# Evolve to t_stellar.
stellar.evolve_model(t_stellar)
channel_from_stellar.copy_attributes(["mass"])
M1 = triple[0].mass
M2 = triple[1].mass
M3 = triple[2].mass
print "t=", stellar.model_time.in_(units.Myr)
print "M=", stellar.particles.mass.in_(units.MSun)
print "R=", stellar.particles.radius.in_(units.RSun)
print "L=", stellar.particles.luminosity.in_(units.LSun)
print "T=", stellar.particles.temperature.in_(units.K)
print "Mdot=", \
-stellar.particles.wind_mass_loss_rate.in_(units.MSun/units.yr)
# Start the dynamics.
# Inner binary:
tmp_stars = Particles(2)
tmp_stars[0].mass = M1
tmp_stars[1].mass = M2
if Pora == 1:
ain_0 = semimajor_axis(Pin_0, M1+M2)
else:
Pin_0 = orbital_period(ain_0, M1+M2)
print 'Pin =', Pin_0
print 'ain_0 =', ain_0
print 'M1+M2 =', M1+M2
print 'Pin_0 =', Pin_0.value_in(units.day), '[day]'
#print 'semi:', semimajor_axis(Pin_0, M1+M2).value_in(units.AU), 'AU'
#print 'period:', orbital_period(ain_0, M1+M2).value_in(units.day), '[day]'
dt_init = 0.01*Pin_0
ma = 180
inc = 60
aop = 180
lon = 0
r,v = get_position(M1, M2, ein_0, ain_0, ma, inc, aop, lon, dt_init)
tmp_stars[1].position = r
tmp_stars[1].velocity = v
tmp_stars.move_to_center()
# Outer binary:
r,v = get_position(M1+M2, M3, eout_0, aout_0, 0, 0, 0, 0, dt_init)
tertiary = Particle()
tertiary.mass = M3
tertiary.position = r
tertiary.velocity = v
tmp_stars.add_particle(tertiary)
tmp_stars.move_to_center()
triple.position = tmp_stars.position
triple.velocity = tmp_stars.velocity
Mtriple = triple.mass.sum()
Pout = orbital_period(aout_0, Mtriple)
print "T=", stellar.model_time.in_(units.Myr)
print "M=", stellar.particles.mass.in_(units.MSun)
print "Pout=", Pout.in_(units.Myr)
print 'tK =', ((M1+M2)/M3)*Pout**2*(1-eout_0**2)**1.5/Pin_0
converter = nbody_system.nbody_to_si(triple.mass.sum(), aout_0)
if integrator == 0:
gravity = Hermite(converter)
gravity.parameters.timestep_parameter = 0.01
elif integrator == 1:
gravity = SmallN(converter)
gravity.parameters.timestep_parameter = 0.01
gravity.parameters.full_unperturbed = 0
elif integrator == 2:
gravity = Huayno(converter)
gravity.parameters.inttype_parameter = 20
gravity.parameters.timestep = (1./256)*Pin_0
else:
gravity = symple(converter)
gravity.parameters.integrator = 10
#gravity.parameters.timestep_parameter = 0.
gravity.parameters.timestep = (1./128)*Pin_0
print gravity.parameters
gravity.particles.add_particles(triple)
channel_from_framework_to_gd = triple.new_channel_to(gravity.particles)
channel_from_gd_to_framework = gravity.particles.new_channel_to(triple)
Etot_init = gravity.kinetic_energy + gravity.potential_energy
Etot_prev = Etot_init
gravity.particles.move_to_center()
# Note: time = t_diag = 0 at the start of the dynamical integration.
dt_diag = t_end/float(nsteps)
t_diag = dt_diag
time = 0.0 | t_end.unit
t_se = t_stellar + time
print 't_end =', t_end
print 'dt_diag =', dt_diag
ain, ein, aout, eout = get_orbital_elements_of_triple(triple)
print "Triple elements t=", time, \
"inner:", triple[0].mass, triple[1].mass, ain, ein, \
"outer:", triple[2].mass, aout, eout
t = [time.value_in(units.Myr)]
Mtot = triple.mass.sum()
mtot = [Mtot.value_in(units.MSun)]
smai = [ain/ain_0]
ecci = [ein/ein_0]
smao = [aout/aout_0]
ecco = [eout/eout_0]
if interp:
# Create arrays of stellar times and masses for interpolation.
times = [time]
masses = [triple.mass.copy()]
while time < t_end:
time += dt_se
stellar.evolve_model(t_stellar+time)
channel_from_stellar.copy_attributes(["mass"])
times.append(time)
masses.append(triple.mass.copy())
time = 0.0 | t_end.unit
print '\ntimes:', times, '\n'
# Evolve the system.
def advance_stellar(t_se, dt):
E0 = gravity.kinetic_energy + gravity.potential_energy
t_se += dt
if interp:
t = t_se-t_stellar
i = int(t/dt_se)
mass = masses[i] + (t-times[i])*(masses[i+1]-masses[i])/dt_se
triple.mass = mass
#print 't_se =', t_se, 'masses =', mass
else:
stellar.evolve_model(t_se)
channel_from_stellar.copy_attributes(["mass"])
channel_from_framework_to_gd.copy_attributes(["mass"])
return t_se, gravity.kinetic_energy + gravity.potential_energy - E0
def advance_gravity(tg, dt):
tg += dt
gravity.evolve_model(tg)
channel_from_gd_to_framework.copy()
return tg
while time < t_end:
if scheme == 1:
# Advance to the next diagnostic time.
dE_se = zero
dt = t_diag - time
if dt > 0|dt.unit:
time = advance_gravity(time, dt)
elif scheme == 2:
# Derive dt from Pin using dtse_fac.
dt = dtse_fac*Pin_0
if time + dt > t_diag: dt = t_diag - time
if dt > 0|dt.unit:
t_se, dE_se = advance_stellar(t_se, dt)
time = advance_gravity(time, dt)
elif scheme == 3:
# Derive dt from Pin using dtse_fac.
dt = dtse_fac*Pin_0
if time + dt > t_diag: dt = t_diag - time
if dt > 0|dt.unit:
time = advance_gravity(time, dt)
t_se, dE_se = advance_stellar(t_se, dt)
elif scheme == 4:
# Derive dt from Pin using dtse_fac.
dt = dtse_fac*Pin_0
if time + dt > t_diag: dt = t_diag - time
if dt > 0|dt.unit:
t_se, dE_se = advance_stellar(t_se, 0.5*dt)
time = advance_gravity(time, dt)
t_se, dE_se2 = advance_stellar(t_se, 0.5*dt)
dE_se += dE_se2
elif scheme == 5:
# Use the specified dt_se.
dE_se = zero
dt = dt_se
if time + dt > t_diag: dt = t_diag - time
if dt > 0|dt.unit:
# For use with symple only: set up average mass loss.
channel_from_stellar.copy_attributes(["mass"])
m0 = triple.mass.copy()
stellar.evolve_model(t_se+dt)
channel_from_stellar.copy_attributes(["mass"])
t_se = stellar.model_time
m1 = triple.mass
dmdt = (m1-m0)/dt
for i in range(len(dmdt)):
gravity.set_dmdt(i, dmdt[i])
time = advance_gravity(time, dt)
else:
print 'unknown option'
sys.exit(0)
if time >= t_diag:
t_diag = time + dt_diag
Ekin = gravity.kinetic_energy
Epot = gravity.potential_energy
Etot = Ekin + Epot
dE = Etot_prev - Etot
Mtot = triple.mass.sum()
print "T=", time,
print "M=", Mtot, "(dM[SE]=", Mtot/Mtriple, ")",
print "E= ", Etot, "Q= ", Ekin/Epot,
print "dE=", (Etot_init-Etot)/Etot, "ddE=", (Etot_prev-Etot)/Etot,
print "(dE[SE]=", dE_se/Etot, ")"
Etot_init -= dE
Etot_prev = Etot
ain, ein, aout, eout = get_orbital_elements_of_triple(triple)
print "Triple elements t=", t_stellar + time, \
"inner:", triple[0].mass, triple[1].mass, ain, ein, \
"outer:", triple[2].mass, aout, eout
t.append(time.value_in(units.yr))
mtot.append(Mtot.value_in(units.MSun))
smai.append(ain/ain_0)
ecci.append(ein/ein_0)
smao.append(aout/aout_0)
ecco.append(eout/eout_0)
if eout > 1 or aout <= zero:
print "Binary ionized or merged"
break
gravity.stop()
stellar.stop()
return t, mtot, smai, ecci, smao, ecco
cluster.particles.add_particles(particles)
# set up bridge; cluster is evolved under influence of the galaxy
sys = bridge(verbose=False)
sys.add_system(cluster, (galaxy, ), False)
# evolve and make plots
times = units.Myr([0., 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4])
f = pyplot.figure(figsize=(16, 8))
for i, t in enumerate(times):
sys.evolve_model(t, timestep=timestep)
print("Evolved the system to time %f" % t)
x = sys.particles.x.value_in(units.parsec)
y = sys.particles.y.value_in(units.parsec)
subplot = f.add_subplot(2, 4, i + 1)
subplot.plot(x, y, 'r .')
subplot.plot([0.], [0.], 'b +')
subplot.set_xlim(-60, 60)
subplot.set_ylim(-60, 60)
subplot.set_title(t)
if i == 7:
subplot.set_xlabel('parsec')
cluster.stop()
galaxy.stop()
pyplot.show()
# pyplot.savefig('test.eps')
def evolve_triple_with_wind(M1, M2, M3, Pora, Pin_0, ain_0, aout_0,
ein_0, eout_0, t_end, nsteps, scheme, dtse_fac):
import random
from amuse.ext.solarsystem import get_position
print "Initial masses:", M1, M2, M3
t_stellar = 4.0|units.Myr
triple = Particles(3)
triple[0].mass = M1
triple[1].mass = M2
triple[2].mass = M3
stellar = SeBa()
stellar.particles.add_particles(triple)
channel_from_stellar = stellar.particles.new_channel_to(triple)
stellar.evolve_model(t_stellar)
channel_from_stellar.copy_attributes(["mass"])
M1 = triple[0].mass
M2 = triple[1].mass
M3 = triple[2].mass
print "T=", stellar.model_time.in_(units.Myr)
print "M=", stellar.particles.mass.in_(units.MSun)
print "Masses at time T:", M1, M2, M3
# Inner binary
tmp_stars = Particles(2)
tmp_stars[0].mass = M1
tmp_stars[1].mass = M2
if Pora == 1:
ain_0 = semimajor_axis(Pin_0, M1+M2)
else:
Pin_0 = orbital_period(ain_0, M1+M2)
print 'ain_0 =', ain_0
print 'M1+M2 =', M1+M2
print 'Pin_0 =', Pin_0.value_in(units.day), '[day]'
#print 'semi:', semimajor_axis(Pin_0, M1+M2).value_in(units.AU), 'AU'
#print 'period:', orbital_period(ain_0, M1+M2).value_in(units.day), '[day]'
dt = 0.1*Pin_0
ma = 180
inc = 30
aop = 180
lon = 0
r, v = get_position(M1, M2, ein_0, ain_0, ma, inc, aop, lon, dt)
tmp_stars[1].position = r
tmp_stars[1].velocity = v
tmp_stars.move_to_center()
# Outer binary
r, v = get_position(M1+M2, M3, eout_0, aout_0, 0, 0, 0, 0, dt)
tertiary = Particle()
tertiary.mass = M3
tertiary.position = r
tertiary.velocity = v
tmp_stars.add_particle(tertiary)
tmp_stars.move_to_center()
triple.position = tmp_stars.position
triple.velocity = tmp_stars.velocity
Mtriple = triple.mass.sum()
Pout = orbital_period(aout_0, Mtriple)
print "T=", stellar.model_time.in_(units.Myr)
print "M=", stellar.particles.mass.in_(units.MSun)
print "Pout=", Pout.in_(units.Myr)
converter = nbody_system.nbody_to_si(triple.mass.sum(), aout_0)
gravity = Hermite(converter)
gravity.particles.add_particles(triple)
channel_from_framework_to_gd = triple.new_channel_to(gravity.particles)
channel_from_gd_to_framework = gravity.particles.new_channel_to(triple)
Etot_init = gravity.kinetic_energy + gravity.potential_energy
Etot_prev = Etot_init
gravity.particles.move_to_center()
time = 0.0 | t_end.unit
ts = t_stellar + time
ain, ein, aout, eout = get_orbital_elements_of_triple(triple)
print "Triple elements t=", time, \
"inner:", triple[0].mass, triple[1].mass, ain, ein, \
"outer:", triple[2].mass, aout, eout
dt_diag = t_end/float(nsteps)
t_diag = dt_diag
t = [time.value_in(units.Myr)]
smai = [ain/ain_0]
ecci = [ein/ein_0]
smao = [aout/aout_0]
ecco = [eout/eout_0]
ain = ain_0
def advance_stellar(ts, dt):
E0 = gravity.kinetic_energy + gravity.potential_energy
ts += dt
stellar.evolve_model(ts)
channel_from_stellar.copy_attributes(["mass"])
channel_from_framework_to_gd.copy_attributes(["mass"])
return ts, gravity.kinetic_energy + gravity.potential_energy - E0
def advance_gravity(tg, dt):
tg += dt
gravity.evolve_model(tg)
channel_from_gd_to_framework.copy()
return tg
while time < t_end:
Pin = orbital_period(ain, triple[0].mass+triple[1].mass)
dt = dtse_fac*Pin
dt *= random.random()
if scheme == 1:
ts, dE_se = advance_stellar(ts, dt)
time = advance_gravity(time, dt)
elif scheme == 2:
time = advance_gravity(time, dt)
ts, dE_se = advance_stellar(ts, dt)
else:
dE_se = zero
#ts, dE_se = advance_stellar(ts, dt/2)
time = advance_gravity(time, dt)
#ts, dE = advance_stellar(ts, dt/2)
#dE_se += dE
if time >= t_diag:
t_diag = time + dt_diag
Ekin = gravity.kinetic_energy
Epot = gravity.potential_energy
Etot = Ekin + Epot
dE = Etot_prev - Etot
Mtot = triple.mass.sum()
print "T=", time,
print "M=", Mtot, "(dM[SE]=", Mtot/Mtriple, ")",
print "E= ", Etot, "Q= ", Ekin/Epot,
print "dE=", (Etot_init-Etot)/Etot, "ddE=", (Etot_prev-Etot)/Etot,
print "(dE[SE]=", dE_se/Etot, ")"
Etot_init -= dE
Etot_prev = Etot
ain, ein, aout, eout = get_orbital_elements_of_triple(triple)
print "Triple elements t=", (4|units.Myr) + time, \
"inner:", triple[0].mass, triple[1].mass, ain, ein, \
"outer:", triple[2].mass, aout, eout
t.append(time.value_in(units.Myr))
smai.append(ain/ain_0)
ecci.append(ein/ein_0)
smao.append(aout/aout_0)
ecco.append(eout/eout_0)
if eout > 1.0 or aout <= zero:
print "Binary ionized or merged"
break
gravity.stop()
stellar.stop()
return t, smai, ecci, smao, ecco
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()
