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_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 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 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 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 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 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_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 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 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 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 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 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 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 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 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 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 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 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 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 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 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()
instance = Hermite(convert_nbody)
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)
def run(self, run_num):
print("Setting up run %d..." % (run_num))
# Create group for run
run_group = self.hdf5_file.create_group(str(run_num))
# create nbody converter thing?
convert_nbody = nbody_system.nbody_to_si(100.0 | units.MSun, 1 | units.parsec)
# initialize particle datamodel
stars = Particles()
print(" Initializing and populating clusters...")
# populate/initialize clusters, add to particle model
for c in self.clusters:
c.populate()
stars.add_particles(c.plummer)
print(" Done!")
# initialize codes
# initialize hermite
print(" Initializing hermite...")
hermite_code = Hermite(convert_nbody)
hermite_code.particles.add_particles(stars)
detect_coll = hermite_code.stopping_conditions.collision_detection
detect_coll.enable()
print(" Done!")
print(" Initializing SSE...")
sse_code = SSE()
sse_code.particles.add_particles(stars)
print("Done!\n")
# actually run the simulation!
print("===== Run #%d =====" % (run_num))
t = 0 # time
i = 1 # iteration num
c = 1 # collision num
while(t < self.runtime):
print(" Time (Myr): %d" % (t))
print(" Simulating...")
# evolve model
hermite_code.evolve_model(t | units.Myr)
sse_code.evolve_model(t | units.Myr)
hermite_code.particles.copy_values_of_attribute_to("position", sse_code.particles)
sse_code.particles.synchronize_to(hermite_code.particles)
if detect_coll.is_set():
print("Detected a collision!!")
print(detect_coll.particles(0))
coll_f = open(sub_folder + "/collision-" + str(c) + "_time" + str(t) + ".txt")
coll_f.write( detect_coll.particles(0) )
coll_f.close()
c += 1
# somehow put a log
# also... eventually, "pause" the rest of the simulation and simulate the collision somehow
#sse_code.particles.copy_values_of_attribute_to("mass", hermite_code.particles)
#sse_code.particles.copy_values_of_attribute_to("stellar_type", hermite_code.particles)
#sse_code.particles.copy_values_of_attribute_to("age", hermite_code.particles)
#sse_code.particles.copy_values_of_attribute_to("luminosity", hermite_code.particles)
#sse_code.particles.copy_values_of_attribute_to("temperature", hermite_code.particles)
#sse_code.particles.copy_values_of_attribute_to("radius", hermite_code.particles)
hermite_code.particles.mass = sse_code.particles.mass
print(" Done.")
# output to csv
print(" Outputting to HDF5...")
#file_name = sub_folder + "/data-" + str(i) + "_time-" + str(t) + ".txt"
self.write_to_hdf5_file(run_group, i, t, stars)
print(" Done.")
#print(" Creating plot...")
#plot_name = "System at " + str(t) + " Myr"
#plot_path = sub_folder + "/plot-" + str(i) + "_time-" + str(t) + ".png"
#plot_data(plot_name, plot_path, hermite_code.particles)
#print(" Done.")
t += self.timestep
i += 1
print("Run complete.\n")
)
subplot.set_xlim(-1, 1)
subplot.set_ylim(-1, 1)
subplot.set_xlabel('x (nbody length)')
subplot.set_ylabel('y (nbody length)')
pyplot.show()
if __name__ == "__main__":
numpy.random.seed(1212)
particles = new_cluster(128)
code = Hermite()
code.particles.add_particles(particles)
stopping_condition = code.stopping_conditions.collision_detection
stopping_condition.enable()
code.evolve_model(4 | nbody_system.time)
if not stopping_condition.is_set():
raise Exception(
"No stopping collision detected in the given timeframe.")
plot_particles_and_highlight_collision(
particles, stopping_condition.particles(0),
stopping_condition.particles(1))
instance.initialize_code()
instance.particles.add_particles(particles)
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)
)
subplot.set_xlim(-1, 1)
subplot.set_ylim(-1, 1)
subplot.set_xlabel('x (nbody length)')
subplot.set_ylabel('y (nbody length)')
pyplot.show()
if __name__ == "__main__":
numpy.random.seed(1212)
particles = new_cluster(128)
code = Hermite()
code.particles.add_particles(particles)
stopping_condition = code.stopping_conditions.collision_detection
stopping_condition.enable()
code.evolve_model(4 | nbody_system.time)
if not stopping_condition.is_set():
raise Exception(
"No stopping collision detected in the given timeframe.")
plot_particles_and_highlight_collision(particles,
stopping_condition.particles(0),
stopping_condition.particles(1))
