def test23(self):
particles = datamodel.Particles(2)
particles.x = [0.0, 10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.vx = 1.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 0.1 | nbody_system.mass
instance = BHTree(redirection="none")
instance.particles.add_particles(particles)
instance.commit_particles()
instance.evolve_model(0.1 | nbody_system.time)
self.assertFalse(instance.particles[0].vy > 0 | nbody_system.speed)
self.assertAlmostRelativeEquals(instance.particles[0].x,
0.1 | nbody_system.length, 4)
instance.particles.new_channel_to(particles).copy()
particles.vy = 1 | nbody_system.speed
particles.new_channel_to(instance.particles).copy()
instance.evolve_model(0.2 | nbody_system.time)
self.assertTrue(instance.particles[0].vy > 0 | nbody_system.speed)
self.assertAlmostRelativeEquals(instance.particles[0].y,
0.1 | nbody_system.length, 4)
instance.stop()
def test19(self):
particles = datamodel.Particles(2)
particles.x = [0.0, 10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = 0.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
very_short_time_to_evolve = 1 | units.s
very_long_time_to_evolve = 1e9 | nbody_system.time
instance = BHTree()
instance.initialize_code()
instance.parameters.stopping_conditions_timeout = very_short_time_to_evolve
self.assertEquals(instance.parameters.stopping_conditions_timeout,
very_short_time_to_evolve)
instance.parameters.epsilon_squared = (0.01 | nbody_system.length)**2
instance.particles.add_particles(particles)
instance.stopping_conditions.timeout_detection.enable()
start = time.time()
instance.evolve_model(very_long_time_to_evolve)
end = time.time()
self.assertTrue(
instance.stopping_conditions.timeout_detection.is_set())
self.assertTrue(
(end - start) < very_short_time_to_evolve.value_in(units.s) +
2) #2 = some overhead compensation
instance.stop()
def test19(self):
particles = datamodel.Particles(2)
particles.x = [0.0,10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = 0.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
very_short_time_to_evolve = 1 | units.s
very_long_time_to_evolve = 1e9 | nbody_system.time
instance = BHTree()
instance.initialize_code()
instance.parameters.stopping_conditions_timeout = very_short_time_to_evolve
self.assertEquals(instance.parameters.stopping_conditions_timeout, very_short_time_to_evolve)
instance.parameters.epsilon_squared = (0.01 | nbody_system.length)**2
instance.particles.add_particles(particles)
instance.stopping_conditions.timeout_detection.enable()
start = time.time()
instance.evolve_model(very_long_time_to_evolve)
end = time.time()
self.assertTrue(instance.stopping_conditions.timeout_detection.is_set())
self.assertTrue((end-start) < very_short_time_to_evolve.value_in(units.s) + 2)#2 = some overhead compensation
instance.stop()
def test17(self):
print "Testing BHTree collision_detection"
particles = datamodel.Particles(7)
particles.mass = 0.001 | nbody_system.mass
particles.radius = 0.01 | nbody_system.length
particles.x = [-101.0, -100.0, -0.5, 0.5, 100.0, 101.0, 104.0] | nbody_system.length
particles.y = 0 | nbody_system.length
particles.z = 0 | nbody_system.length
particles.velocity = [[2, 0, 0], [-2, 0, 0]]*3 + [[-4, 0, 0]] | nbody_system.speed
instance = BHTree(redirection='none')
instance.initialize_code()
instance.parameters.set_defaults()
# Uncommenting any of the following two lines will suppress collision detection
#~ instance.parameters.use_self_gravity = 0
#~ instance.parameters.epsilon_squared = 0.0 | nbody_system.length**2
instance.parameters.opening_angle = 0.1
instance.particles.add_particles(particles)
collisions = instance.stopping_conditions.collision_detection
collisions.enable()
instance.evolve_model(1.0 | nbody_system.time)
self.assertTrue(collisions.is_set())
self.assertTrue(instance.model_time < 0.5 | nbody_system.time)
self.assertEquals(len(collisions.particles(0)), 3)
self.assertEquals(len(collisions.particles(1)), 3)
self.assertEquals(len(particles - collisions.particles(0) - collisions.particles(1)), 1)
self.assertEquals(abs(collisions.particles(0).x - collisions.particles(1).x) <
(collisions.particles(0).radius + collisions.particles(1).radius),
[True, True, True])
sticky_merged = datamodel.Particles(len(collisions.particles(0)))
sticky_merged.mass = collisions.particles(0).mass + collisions.particles(1).mass
sticky_merged.radius = collisions.particles(0).radius
for p1, p2, merged in zip(collisions.particles(0), collisions.particles(1), sticky_merged):
merged.position = (p1 + p2).center_of_mass()
merged.velocity = (p1 + p2).center_of_mass_velocity()
print instance.model_time
print instance.particles
instance.particles.remove_particles(collisions.particles(0) + collisions.particles(1))
instance.particles.add_particles(sticky_merged)
instance.evolve_model(1.0 | nbody_system.time)
print
print instance.model_time
print instance.particles
self.assertTrue(collisions.is_set())
self.assertTrue(instance.model_time < 1.0 | nbody_system.time)
self.assertEquals(len(collisions.particles(0)), 1)
self.assertEquals(len(collisions.particles(1)), 1)
self.assertEquals(len(instance.particles - collisions.particles(0) - collisions.particles(1)), 2)
self.assertEquals(abs(collisions.particles(0).x - collisions.particles(1).x) <
(collisions.particles(0).radius + collisions.particles(1).radius),
[True])
instance.stop()
def test2(self):
#not completed
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun,
149.5e6 | units.km)
instance = BHTree(convert_nbody)
#instance.dt_dia = 1
instance.parameters.epsilon_squared = 0.001 | units.AU**2
#instance.timestep = 0.0001
#instance.use_self_gravity = 0
instance.commit_parameters()
stars = datamodel.Stars(2)
sun = stars[0]
sun.mass = units.MSun(1.0)
sun.position = units.m(numpy.array((0.0, 0.0, 0.0)))
sun.velocity = units.ms(numpy.array((0.0, 0.0, 0.0)))
sun.radius = units.RSun(1.0)
earth = stars[1]
earth.mass = units.kg(5.9736e24)
earth.radius = units.km(6371)
earth.position = units.km(numpy.array((149.5e6, 0.0, 0.0)))
earth.velocity = units.ms(numpy.array((0.0, 29800, 0.0)))
instance.particles.add_particles(stars)
instance.commit_particles()
self.assertAlmostRelativeEquals(sun.radius,
instance.particles[0].radius)
for x in range(1, 2000, 10):
instance.evolve_model(x | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
stars.savepoint()
if HAS_MATPLOTLIB:
figure = pyplot.figure()
plot = figure.add_subplot(1, 1, 1)
x_points = earth.get_timeline_of_attribute("x")
y_points = earth.get_timeline_of_attribute("y")
x_points_in_AU = map(lambda (t, x): x.value_in(units.AU), x_points)
y_points_in_AU = map(lambda (t, x): x.value_in(units.AU), y_points)
plot.scatter(x_points_in_AU, y_points_in_AU, color="b", marker='o')
plot.set_xlim(-1.5, 1.5)
plot.set_ylim(-1.5, 1.5)
test_results_path = self.get_path_to_results()
output_file = os.path.join(test_results_path,
"bhtree-earth-sun.svg")
figure.savefig(output_file)
instance.cleanup_code()
instance.stop()
def test2(self):
#not completed
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = BHTree(convert_nbody)
#instance.dt_dia = 1
instance.parameters.epsilon_squared = 0.001 | units.AU**2
#instance.timestep = 0.0001
#instance.use_self_gravity = 0
instance.commit_parameters()
stars = datamodel.Stars(2)
sun = stars[0]
sun.mass = units.MSun(1.0)
sun.position = units.m(numpy.array((0.0,0.0,0.0)))
sun.velocity = units.ms(numpy.array((0.0,0.0,0.0)))
sun.radius = units.RSun(1.0)
earth = stars[1]
earth.mass = units.kg(5.9736e24)
earth.radius = units.km(6371)
earth.position = units.km(numpy.array((149.5e6,0.0,0.0)))
earth.velocity = units.ms(numpy.array((0.0,29800,0.0)))
instance.particles.add_particles(stars)
instance.commit_particles()
self.assertAlmostRelativeEquals(sun.radius, instance.particles[0].radius)
for x in range(1,2000,10):
instance.evolve_model(x | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
stars.savepoint()
if HAS_MATPLOTLIB:
figure = pyplot.figure()
plot = figure.add_subplot(1,1,1)
x_points = earth.get_timeline_of_attribute("x")
y_points = earth.get_timeline_of_attribute("y")
x_points_in_AU = map(lambda (t,x) : x.value_in(units.AU), x_points)
y_points_in_AU = map(lambda (t,x) : x.value_in(units.AU), y_points)
plot.scatter(x_points_in_AU,y_points_in_AU, color = "b", marker = 'o')
plot.set_xlim(-1.5, 1.5)
plot.set_ylim(-1.5, 1.5)
test_results_path = self.get_path_to_results()
output_file = os.path.join(test_results_path, "bhtree-earth-sun.svg")
figure.savefig(output_file)
instance.cleanup_code()
instance.stop()
def nbody_integrator(Ncl, mcl, rcl, t_end, n_steps, escape_velocity_fraction,
R):
converter = nbody_system.nbody_to_si(mcl, rcl)
bodies = new_plummer_model(Ncl, convert_nbody=converter)
#estimate of milky way mass by "Mass models of the Milky Way", McMillan
blackhole_mass = 1.26e12 | units.MSun
blackhole = Particle(mass=blackhole_mass)
blackhole.position = [0, 0, 0] | units.m
cluster_velocity = [0, 0, 0] | units.m / units.s
cluster_position = [0, 0, 0] | units.parsec
cluster_position[0] = R
G_si = converter.to_si(nbody_system.G)
escape_v = (2 * G_si * blackhole_mass / R).sqrt().as_quantity_in(units.m /
units.s)
V = escape_v * escape_velocity_fraction
cluster_velocity[1] = V
bodies.move_to_center()
bodies.velocity += cluster_velocity
bodies.position += cluster_position
bodies.add_particle(blackhole)
gravity = BHTree(converter)
gravity.particles.add_particles(bodies)
channel_from_gravity_to_framework = gravity.particles.\
new_channel_to(bodies)
time = zero
dt = t_end / float(n_steps)
x = 0
base_path = "encounter_plots/"+str(R.value_in(units.parsec))+"_"+\
str(escape_velocity_fraction)+"_"
while time < t_end:
plot_cluster(bodies, base_path + str(x), time, rcl, V)
time += dt
gravity.evolve_model(time)
channel_from_gravity_to_framework.copy()
x += 1
plot_cluster(bodies, base_path + str(x), time, rcl, V)
gravity.stop()
return V, bodies
def nbody_integrator(Ncl, mcl, rcl, t_end, n_steps, escape_velocity_fraction, R):
converter = nbody_system.nbody_to_si(mcl, rcl)
bodies = new_plummer_model(Ncl, convert_nbody=converter)
#estimate of milky way mass by "Mass models of the Milky Way", McMillan
blackhole_mass = 1.26e12 | units.MSun
blackhole = Particle(mass=blackhole_mass)
blackhole.position = [0,0,0] | units.m
cluster_velocity = [0,0,0] | units.m / units.s
cluster_position = [0,0,0] | units.parsec
cluster_position[0] = R
G_si = converter.to_si(nbody_system.G)
escape_v = (2*G_si*blackhole_mass/R).sqrt().as_quantity_in(units.m/units.s)
V = escape_v * escape_velocity_fraction
cluster_velocity[1] = V
bodies.move_to_center()
bodies.velocity += cluster_velocity
bodies.position += cluster_position
bodies.add_particle(blackhole)
gravity = BHTree(converter)
gravity.particles.add_particles(bodies)
channel_from_gravity_to_framework = gravity.particles.\
new_channel_to(bodies)
time = zero
dt = t_end / float(n_steps)
x = 0
base_path = "encounter_plots/"+str(R.value_in(units.parsec))+"_"+\
str(escape_velocity_fraction)+"_"
while time < t_end:
plot_cluster(bodies, base_path+str(x),time, rcl, V)
time += dt
gravity.evolve_model(time)
channel_from_gravity_to_framework.copy()
x+=1
plot_cluster(bodies, base_path+str(x),time, rcl, V)
gravity.stop()
return V, bodies
def test15(self):
print "Test15: Testing effect of BHTree parameter epsilon_squared"
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun,
1.0 | units.AU)
particles = datamodel.Particles(2)
sun = particles[0]
sun.mass = 1.0 | units.MSun
sun.position = [0.0, 0.0, 0.0] | units.AU
sun.velocity = [0.0, 0.0, 0.0] | units.AU / units.yr
sun.radius = 1.0 | units.RSun
earth = particles[1]
earth.mass = 5.9736e24 | units.kg
earth.radius = 6371.0 | units.km
earth.position = [0.0, 1.0, 0.0] | units.AU
earth.velocity = [2.0 * numpy.pi, -0.0001, 0.0] | units.AU / units.yr
initial_direction = math.atan((earth.velocity[0] / earth.velocity[1]))
final_direction = []
for log_eps2 in range(-9, 10, 2):
instance = BHTree(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 10.0**log_eps2 | units.AU**2
instance.particles.add_particles(particles)
instance.commit_particles()
instance.evolve_model(0.25 | units.yr)
final_direction.append(
math.atan((instance.particles[1].velocity[0] /
instance.particles[1].velocity[1])))
instance.stop()
# Small values of epsilon_squared should result in normal earth-sun dynamics: rotation of 90 degrees
self.assertAlmostEquals(abs(final_direction[0]),
abs(initial_direction + math.pi / 2.0), 2)
# Large values of epsilon_squared should result in ~ no interaction
self.assertAlmostEquals(final_direction[-1], initial_direction, 2)
# Outcome is most sensitive to epsilon_squared when epsilon_squared = d(earth, sun)^2
delta = [
abs(final_direction[i + 1] - final_direction[i])
for i in range(len(final_direction) - 1)
]
self.assertEquals(delta[len(final_direction) // 2 - 1], max(delta))
def test18(self):
particles = datamodel.Particles(2)
particles.x = [0.0,10.0] | nbody_system.length
particles.y = 0 | nbody_system.length
particles.z = 0 | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = 0 | nbody_system.speed
particles.vy = 0 | nbody_system.speed
particles.vz = 0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
instance = BHTree()
instance.initialize_code()
instance.parameters.stopping_conditions_number_of_steps = 2
self.assertEquals(instance.parameters.stopping_conditions_number_of_steps, 2)
instance.parameters.epsilon_squared = (0.01 | nbody_system.length)**2
instance.particles.add_particles(particles)
instance.stopping_conditions.number_of_steps_detection.enable()
instance.evolve_model(10 | nbody_system.time)
self.assertTrue(instance.stopping_conditions.number_of_steps_detection.is_set())
self.assertTrue(instance.model_time < 10 | nbody_system.time)
instance.stop()
def test3(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = BHTree(convert_nbody)
#instance.dt_dia = 1
instance.parameters.epsilon_squared = 0.001 | units.AU**2
#instance.timestep = 0.0001
#instance.use_self_gravity = 0
instance.commit_parameters()
stars = datamodel.Stars(2)
star1 = stars[0]
star2 = stars[1]
star1.mass = units.MSun(1.0)
star1.position = units.AU(numpy.array((-.10,0.0,0.0)))
star1.velocity = units.AUd(numpy.array((0.0,0.0,0.0)))
star1.radius = units.RSun(1.0)
star2.mass = units.MSun(1.0)
star2.position = units.AU(numpy.array((.10,0.0,0.0)))
star2.velocity = units.AUd(numpy.array((0.0,0.0,0.0)))
star2.radius = units.RSun(100.0)
instance.particles.add_particles(stars)
instance.commit_particles()
for x in range(1,200,1):
instance.evolve_model(x | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
#instance.get_indices_of_colliding_particles()
#print stars[0].position-stars[1].position
stars.savepoint()
instance.cleanup_code()
instance.stop()
def test3(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun,
149.5e6 | units.km)
instance = BHTree(convert_nbody)
#instance.dt_dia = 1
instance.parameters.epsilon_squared = 0.001 | units.AU**2
#instance.timestep = 0.0001
#instance.use_self_gravity = 0
instance.commit_parameters()
stars = datamodel.Stars(2)
star1 = stars[0]
star2 = stars[1]
star1.mass = units.MSun(1.0)
star1.position = units.AU(numpy.array((-.10, 0.0, 0.0)))
star1.velocity = units.AUd(numpy.array((0.0, 0.0, 0.0)))
star1.radius = units.RSun(1.0)
star2.mass = units.MSun(1.0)
star2.position = units.AU(numpy.array((.10, 0.0, 0.0)))
star2.velocity = units.AUd(numpy.array((0.0, 0.0, 0.0)))
star2.radius = units.RSun(100.0)
instance.particles.add_particles(stars)
instance.commit_particles()
for x in range(1, 200, 1):
instance.evolve_model(x | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
#instance.get_indices_of_colliding_particles()
#print stars[0].position-stars[1].position
stars.savepoint()
instance.cleanup_code()
instance.stop()
def test15(self):
print "Test15: Testing effect of BHTree parameter epsilon_squared"
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 1.0 | units.AU)
particles = datamodel.Particles(2)
sun = particles[0]
sun.mass = 1.0 | units.MSun
sun.position = [0.0, 0.0, 0.0] | units.AU
sun.velocity = [0.0, 0.0, 0.0] | units.AU / units.yr
sun.radius = 1.0 | units.RSun
earth = particles[1]
earth.mass = 5.9736e24 | units.kg
earth.radius = 6371.0 | units.km
earth.position = [0.0, 1.0, 0.0] | units.AU
earth.velocity = [2.0*numpy.pi, -0.0001, 0.0] | units.AU / units.yr
initial_direction = math.atan((earth.velocity[0]/earth.velocity[1]))
final_direction = []
for log_eps2 in range(-9,10,2):
instance = BHTree(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 10.0**log_eps2 | units.AU ** 2
instance.particles.add_particles(particles)
instance.commit_particles()
instance.evolve_model(0.25 | units.yr)
final_direction.append(math.atan((instance.particles[1].velocity[0]/
instance.particles[1].velocity[1])))
instance.stop()
# Small values of epsilon_squared should result in normal earth-sun dynamics: rotation of 90 degrees
self.assertAlmostEquals(abs(final_direction[0]), abs(initial_direction+math.pi/2.0), 2)
# Large values of epsilon_squared should result in ~ no interaction
self.assertAlmostEquals(final_direction[-1], initial_direction, 2)
# Outcome is most sensitive to epsilon_squared when epsilon_squared = d(earth, sun)^2
delta = [abs(final_direction[i+1]-final_direction[i]) for i in range(len(final_direction)-1)]
self.assertEquals(delta[len(final_direction)//2 -1], max(delta))
def test23(self):
particles = datamodel.Particles(2)
particles.x = [0.0,10.0] | nbody_system.length
particles.y = 0.0 | nbody_system.length
particles.z = 0.0 | nbody_system.length
particles.vx = 1.0 | nbody_system.speed
particles.vy = 0.0 | nbody_system.speed
particles.vz = 0.0 | nbody_system.speed
particles.mass = 0.1 | nbody_system.mass
instance = BHTree(redirection="none")
instance.particles.add_particles(particles)
instance.commit_particles()
instance.evolve_model(0.1 | nbody_system.time)
self.assertFalse(instance.particles[0].vy > 0| nbody_system.speed)
self.assertAlmostRelativeEquals(instance.particles[0].x , 0.1 | nbody_system.length, 4)
instance.particles.new_channel_to(particles).copy()
particles.vy = 1| nbody_system.speed
particles.new_channel_to(instance.particles).copy()
instance.evolve_model(0.2 | nbody_system.time)
self.assertTrue(instance.particles[0].vy > 0| nbody_system.speed)
self.assertAlmostRelativeEquals(instance.particles[0].y , 0.1 | nbody_system.length, 4)
instance.stop()
def test18(self):
particles = datamodel.Particles(2)
particles.x = [0.0, 10.0] | nbody_system.length
particles.y = 0 | nbody_system.length
particles.z = 0 | nbody_system.length
particles.radius = 0.005 | nbody_system.length
particles.vx = 0 | nbody_system.speed
particles.vy = 0 | nbody_system.speed
particles.vz = 0 | nbody_system.speed
particles.mass = 1.0 | nbody_system.mass
instance = BHTree()
instance.initialize_code()
instance.parameters.stopping_conditions_number_of_steps = 2
self.assertEquals(
instance.parameters.stopping_conditions_number_of_steps, 2)
instance.parameters.epsilon_squared = (0.01 | nbody_system.length)**2
instance.particles.add_particles(particles)
instance.stopping_conditions.number_of_steps_detection.enable()
instance.evolve_model(10 | nbody_system.time)
self.assertTrue(
instance.stopping_conditions.number_of_steps_detection.is_set())
self.assertTrue(instance.model_time < 10 | nbody_system.time)
instance.stop()
def test1(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun,
149.5e6 | units.km)
instance = BHTree(convert_nbody)
instance.parameters.epsilon_squared = 0.001 | units.AU**2
stars = datamodel.Stars(2)
sun = stars[0]
sun.mass = units.MSun(1.0)
sun.position = [0.0, 0.0, 0.0] | units.m
sun.velocity = [0.0, 0.0, 0.0] | units.ms
sun.radius = units.RSun(1.0)
earth = stars[1]
earth.mass = units.kg(5.9736e24)
earth.radius = units.km(6371)
earth.position = [149.5e6, 0.0, 0.0] | units.km
earth.velocity = [0.0, 29800, 0.0] | units.ms
#instance.particles.add_particles(stars)
instance.particles.add_particles(stars)
postion_at_start = earth.position.value_in(units.AU)[0]
instance.evolve_model(365.0 | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
postion_after_full_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostEqual(postion_at_start, postion_after_full_rotation,
3)
instance.evolve_model(365.0 + (365.0 / 2) | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
postion_after_half_a_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostEqual(-postion_at_start,
postion_after_half_a_rotation, 2)
instance.evolve_model(365.0 + (365.0 / 2) + (365.0 / 4) | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
postion_after_half_a_rotation = earth.position.value_in(units.AU)[1]
self.assertAlmostEqual(-postion_at_start,
postion_after_half_a_rotation, 1)
instance.cleanup_code()
instance.stop()
def test1(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = BHTree(convert_nbody)
instance.parameters.epsilon_squared = 0.001 | units.AU**2
stars = datamodel.Stars(2)
sun = stars[0]
sun.mass = units.MSun(1.0)
sun.position = [0.0,0.0,0.0] | units.m
sun.velocity = [0.0,0.0,0.0] | units.ms
sun.radius = units.RSun(1.0)
earth = stars[1]
earth.mass = units.kg(5.9736e24)
earth.radius = units.km(6371)
earth.position = [149.5e6, 0.0, 0.0] | units.km
earth.velocity = [0.0, 29800, 0.0] | units.ms
#instance.particles.add_particles(stars)
instance.particles.add_particles(stars)
postion_at_start = earth.position.value_in(units.AU)[0]
instance.evolve_model(365.0 | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
postion_after_full_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostEqual(postion_at_start, postion_after_full_rotation, 3)
instance.evolve_model(365.0 + (365.0 / 2) | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
postion_after_half_a_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostEqual(-postion_at_start, postion_after_half_a_rotation, 2)
instance.evolve_model(365.0 + (365.0 / 2) + (365.0 / 4) | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
postion_after_half_a_rotation = earth.position.value_in(units.AU)[1]
self.assertAlmostEqual(-postion_at_start, postion_after_half_a_rotation, 1)
instance.cleanup_code()
instance.stop()
def simulate_small_cluster(number_of_stars, end_time = 40 | units.Myr,
name_of_the_figure = "test-2.svg"):
#numpy.random.seed(1)
salpeter_masses = new_salpeter_mass_distribution(number_of_stars)
total_mass = salpeter_masses.sum()
convert_nbody = nbody_system.nbody_to_si(total_mass, 1.0 | units.parsec)
particles = new_plummer_model(number_of_stars, convert_nbody);
gravity = BHTree(convert_nbody)
gravity.initialize_code()
#gravity.parameters.set_defaults()
#print gravity.parameters.timestep.as_quantity_in(units.Myr)
gravity.parameters.timestep = 0.0001 | units.Myr # tiny!
gravity.parameters.epsilon_squared \
= (float(number_of_stars)**(-0.333333) | units.parsec) ** 2
stellar_evolution = SSE()
stellar_evolution.initialize_module_with_default_parameters()
print "setting masses of the stars"
particles.radius = 0.0 | units.RSun
particles.mass = salpeter_masses
print "initializing the particles"
stellar_evolution.particles.add_particles(particles)
from_stellar_evolution_to_model \
= stellar_evolution.particles.new_channel_to(particles)
from_stellar_evolution_to_model.copy_attributes(["mass"])
print "centering the particles"
particles.move_to_center()
print "scaling particles to viridial equilibrium"
particles.scale_to_standard(convert_nbody)
gravity.particles.add_particles(particles)
from_model_to_gravity = particles.new_channel_to(gravity.particles)
from_gravity_to_model = gravity.particles.new_channel_to(particles)
gravity.commit_particles()
time = 0.0 | units.Myr
particles.savepoint(time)
total_energy_at_t0 = gravity.kinetic_energy + gravity.potential_energy
print "evolving the model until t = " + str(end_time)
while time < end_time:
time += 0.25 | units.Myr
print "gravity evolve step starting"
gravity.evolve_model(time)
print "gravity evolve step done"
print "stellar evolution step starting"
stellar_evolution.evolve_model(time)
print "stellar evolution step done"
from_gravity_to_model.copy()
from_stellar_evolution_to_model.copy_attributes(["mass", "radius"])
particles.savepoint(time)
from_model_to_gravity.copy_attributes(["mass"])
total_energy_at_this_time \
= gravity.kinetic_energy + gravity.potential_energy
print_log(time, gravity, particles,
total_energy_at_t0, total_energy_at_this_time)
test_results_path = get_path_to_results()
output_file = os.path.join(test_results_path, "small.hdf5")
if os.path.exists(output_file):
os.remove(output_file)
storage = store.StoreHDF(output_file)
storage.store(particles)
gravity.stop()
stellar_evolution.stop()
plot_particles(particles, name_of_the_figure)
def test17(self):
print "Testing BHTree collision_detection"
particles = datamodel.Particles(7)
particles.mass = 0.001 | nbody_system.mass
particles.radius = 0.01 | nbody_system.length
particles.x = [-101.0, -100.0, -0.5, 0.5, 100.0, 101.0, 104.0
] | nbody_system.length
particles.y = 0 | nbody_system.length
particles.z = 0 | nbody_system.length
particles.velocity = [[2, 0, 0], [-2, 0, 0]
] * 3 + [[-4, 0, 0]] | nbody_system.speed
instance = BHTree(redirection='none')
instance.initialize_code()
instance.parameters.set_defaults()
# Uncommenting any of the following two lines will suppress collision detection
#~ instance.parameters.use_self_gravity = 0
#~ instance.parameters.epsilon_squared = 0.0 | nbody_system.length**2
instance.parameters.opening_angle = 0.1
instance.particles.add_particles(particles)
collisions = instance.stopping_conditions.collision_detection
collisions.enable()
instance.evolve_model(1.0 | nbody_system.time)
self.assertTrue(collisions.is_set())
self.assertTrue(instance.model_time < 0.5 | nbody_system.time)
self.assertEquals(len(collisions.particles(0)), 3)
self.assertEquals(len(collisions.particles(1)), 3)
self.assertEquals(
len(particles - collisions.particles(0) - collisions.particles(1)),
1)
self.assertEquals(
abs(collisions.particles(0).x - collisions.particles(1).x) <
(collisions.particles(0).radius + collisions.particles(1).radius),
[True, True, True])
sticky_merged = datamodel.Particles(len(collisions.particles(0)))
sticky_merged.mass = collisions.particles(
0).mass + collisions.particles(1).mass
sticky_merged.radius = collisions.particles(0).radius
for p1, p2, merged in zip(collisions.particles(0),
collisions.particles(1), sticky_merged):
merged.position = (p1 + p2).center_of_mass()
merged.velocity = (p1 + p2).center_of_mass_velocity()
print instance.model_time
print instance.particles
instance.particles.remove_particles(
collisions.particles(0) + collisions.particles(1))
instance.particles.add_particles(sticky_merged)
instance.evolve_model(1.0 | nbody_system.time)
print
print instance.model_time
print instance.particles
self.assertTrue(collisions.is_set())
self.assertTrue(instance.model_time < 1.0 | nbody_system.time)
self.assertEquals(len(collisions.particles(0)), 1)
self.assertEquals(len(collisions.particles(1)), 1)
self.assertEquals(
len(instance.particles - collisions.particles(0) -
collisions.particles(1)), 2)
self.assertEquals(
abs(collisions.particles(0).x - collisions.particles(1).x) <
(collisions.particles(0).radius + collisions.particles(1).radius),
[True])
instance.stop()
def simulate_small_cluster(number_of_stars,
end_time=40 | units.Myr,
name_of_the_figure="test-2.svg"):
# numpy.random.seed(1)
salpeter_masses = new_salpeter_mass_distribution(number_of_stars)
total_mass = salpeter_masses.sum()
convert_nbody = nbody_system.nbody_to_si(total_mass, 1.0 | units.parsec)
particles = new_plummer_model(number_of_stars, convert_nbody)
gravity = BHTree(convert_nbody)
# print gravity.parameters.timestep.as_quantity_in(units.Myr)
gravity.parameters.timestep = 0.0001 | units.Myr # tiny!
gravity.parameters.epsilon_squared \
= (float(number_of_stars)**(-0.333333) | units.parsec) ** 2
stellar_evolution = SSE()
print "setting masses of the stars"
particles.radius = 0.0 | units.RSun
particles.mass = salpeter_masses
print "initializing the particles"
stellar_evolution.particles.add_particles(particles)
from_stellar_evolution_to_model \
= stellar_evolution.particles.new_channel_to(particles)
from_stellar_evolution_to_model.copy_attributes(["mass"])
print "centering the particles"
particles.move_to_center()
print "scaling particles to viridial equilibrium"
particles.scale_to_standard(convert_nbody)
gravity.particles.add_particles(particles)
from_model_to_gravity = particles.new_channel_to(gravity.particles)
from_gravity_to_model = gravity.particles.new_channel_to(particles)
time = 0.0 | units.Myr
particles.savepoint(time)
total_energy_at_t0 = gravity.kinetic_energy + gravity.potential_energy
print "evolving the model until t = " + str(end_time)
while time < end_time:
time += 0.25 | units.Myr
print "gravity evolve step starting"
gravity.evolve_model(time)
print "gravity evolve step done"
print "stellar evolution step starting"
stellar_evolution.evolve_model(time)
print "stellar evolution step done"
from_gravity_to_model.copy()
from_stellar_evolution_to_model.copy_attributes(["mass", "radius"])
particles.savepoint(time)
from_model_to_gravity.copy_attributes(["mass"])
total_energy_at_this_time \
= gravity.kinetic_energy + gravity.potential_energy
print_log(time, gravity, particles, total_energy_at_t0,
total_energy_at_this_time)
test_results_path = get_path_to_results()
output_file = os.path.join(test_results_path, "small.hdf5")
if os.path.exists(output_file):
os.remove(output_file)
storage = store.StoreHDF(output_file)
storage.store(particles)
gravity.stop()
stellar_evolution.stop()
plot_particles(particles, name_of_the_figure)
def assignment_2d():
current_cluster_mass = 400 | units.MSun
initial_mass_fraction = 0.84
desired_initial_mass = current_cluster_mass / initial_mass_fraction
masses = new_salpeter_mass_distribution(100000)
mean_salpeter_mass = masses.mean()
print "mean salpeter mass", mean_salpeter_mass
N = int(desired_initial_mass / mean_salpeter_mass)
print "N", N
Rvir = 10 | units.lightyear
z = 0.17
masses = new_salpeter_mass_distribution(N)
converter = nbody_system.nbody_to_si(masses.sum(), Rvir)
G_SI = converter.to_si(nbody_system.G)
bodies = new_plummer_sphere(N, convert_nbody=converter)
bodies.mass = masses
bodies.metalicity = z
# start the gravity solver
gravity = BHTree(converter)
gravity.initialize_code()
gravity.parameters.timestep = 0.1 | units.Myr
# start the stellar evolution solver
stellar = SSE()
stars = stellar.particles.add_particles(bodies)
from_stellar_evolution_to_model \
= stellar.particles.new_channel_to(bodies)
from_stellar_evolution_to_model.copy_attributes(["mass"])
bodies.scale_to_standard(converter)
gravity.particles.add_particles(bodies)
from_model_to_gravity = bodies.new_channel_to(gravity.particles)
from_gravity_to_model = gravity.particles.new_channel_to(bodies)
gravity.commit_particles()
end_time = 1000 | units.Myr
current_time = 0 | units.Myr
cluster = "Hyades"
bound_stars_counts = []
main_sequence_stars_counts = []
giant_stars_counts = []
remnant_stars_counts = []
max_radii = [] | units.parsec
virial_radii = [] | units.parsec
times = [] | units.Myr
while current_time < end_time:
name_of_the_figure = "isochrone_with_grav_"+str(int(current_time.value_in(units.Myr)))+".png"
gravity.evolve_model(current_time)
stellar.evolve_model(current_time)
from_gravity_to_model.copy()
from_stellar_evolution_to_model.copy_attributes(["mass", "radius"])
from_model_to_gravity.copy_attributes(["mass"])
remnant_count = 0
main_sequence_count = 0
giant_count = 0
for star in stars:
if stellar_remnant_state(star):
remnant_count += 1
if stellar_giant_state(star):
giant_count += 1
if stellar_main_sequence_state(star):
main_sequence_count += 1
max_radius = bodies.total_radius()
virial_radius = bodies.virial_radius()
bound_star_count = len(bodies.bound_subset(unit_converter=converter, G=G_SI))
print "bound stars:", bound_star_count
print "main sequence stars:", main_sequence_count
print "giant stars:", giant_count
print "remnant stars:", remnant_count
print "cluster radius(max from centre):", max_radius
print "virial radius:", virial_radius
print current_time
times.append(current_time)
remnant_stars_counts.append(remnant_count)
giant_stars_counts.append(giant_count)
main_sequence_stars_counts.append(main_sequence_count)
max_radii.append(max_radius)
virial_radii.append(virial_radius)
bound_stars_counts.append(bound_star_count)
temperatures = stars.temperature
luminosities = stars.luminosity
plot_HR_diagram(temperatures, luminosities,
cluster+"/",
name_of_the_figure, current_time)
current_time += 10 | units.Myr
data = {}
data["bound_stars_at_time"] = bound_stars_counts
data["remnant_stars_at_time"] = remnant_stars_counts
data["giant_stars_at_time"] = giant_stars_counts
data["main_sequence_stars_at_time"] = main_sequence_stars_counts
data["max_radius_at_time"] = max_radii
data["virial_radii"] = virial_radii
data["times"] = times
pickle.dump(data, open(cluster+"/assignment2d.dat", "wb"))
