def simulate_small_cluster(number_of_stars,
end_time=40 | units.Myr,
name_of_the_figure="test-2.svg"):
random.seed()
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)
convert_nbody.set_as_default()
particles = new_plummer_model(number_of_stars, convert_nbody)
gravity = PhiGRAPE(convert_nbody, mode="gpu")
gravity.initialize_code()
gravity.parameters.timestep_parameter = 0.01
gravity.parameters.initial_timestep_parameter = 0.01
gravity.parameters.epsilon_squared = 0.000001 | 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
#comment out to get plummer masses
particles.mass = salpeter_masses
gravity.particles.add_particles(particles)
gravity.initialize_particles(0.0)
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)
move_particles_to_center_of_mass(particles)
kineticEnergy = gravity.kinetic_energy.value_in(units.J)
potentialEnergy = gravity.potential_energy.value_in(units.J)
ToverV = kineticEnergy / potentialEnergy
file.write(str(time.value_in(units.Myr)))
file.write(' ')
file.write(str(ToverV))
file.write('\n')
while time < end_time:
time += 0.25 | units.Myr
gravity.evolve_model(time)
from_gravity_to_model.copy()
print "Evolved model to t =", str(time)
print "Evolved model to t =", str(
convert_nbody.to_nbody(time.value_in(units.Myr) | units.Myr))
kineticEnergy = gravity.kinetic_energy.value_in(units.J)
potentialEnergy = gravity.potential_energy.value_in(units.J)
ToverV = kineticEnergy / potentialEnergy
print "Kin / Pot =", ToverV
#print "Particle Mass =", particles[1].mass
file.write(str(time.value_in(units.Myr)))
file.write(' ')
file.write(str(ToverV))
file.write('\n')
file.close()
if os.path.exists('small.hdf5'):
os.remove('small.hdf5')
storage = store.StoreHDF("small.hdf5")
storage.store(particles)
del gravity
del stellar_evolution
def simulate_small_cluster(number_of_stars, end_time=40 | units.Myr,
name_of_the_figure="test-2.svg"):
# numpy.random.seed(1)
salpeter_masses = new_salpeter_mass_distribution(number_of_stars)
total_mass = salpeter_masses.sum()
convert_nbody = nbody_system.nbody_to_si(total_mass, 1.0 | units.parsec)
particles = new_plummer_model(number_of_stars, convert_nbody)
gravity = BHTree(convert_nbody)
gravity.initialize_code()
# gravity.parameters.set_defaults()
# print gravity.parameters.timestep.as_quantity_in(units.Myr)
gravity.parameters.timestep = 0.0001 | units.Myr # tiny!
gravity.parameters.epsilon_squared \
= (float(number_of_stars)**(-0.333333) | units.parsec) ** 2
stellar_evolution = SSE()
stellar_evolution.initialize_module_with_default_parameters()
print "setting masses of the stars"
particles.radius = 0.0 | units.RSun
particles.mass = salpeter_masses
print "initializing the particles"
stellar_evolution.particles.add_particles(particles)
from_stellar_evolution_to_model \
= stellar_evolution.particles.new_channel_to(particles)
from_stellar_evolution_to_model.copy_attributes(["mass"])
print "centering the particles"
particles.move_to_center()
print "scaling particles to viridial equilibrium"
particles.scale_to_standard(convert_nbody)
gravity.particles.add_particles(particles)
from_model_to_gravity = particles.new_channel_to(gravity.particles)
from_gravity_to_model = gravity.particles.new_channel_to(particles)
gravity.commit_particles()
time = 0.0 | units.Myr
particles.savepoint(time)
total_energy_at_t0 = gravity.kinetic_energy + gravity.potential_energy
print "evolving the model until t = " + str(end_time)
while time < end_time:
time += 0.25 | units.Myr
print "Gravity evolve step starting"
gravity_evolve = gravity.evolve_model.async(time)
print "Stellar evolution step starting"
stellar_evolution_evolve = stellar_evolution.evolve_model(time)
print "Stellar evolution step done."
gravity_evolve.result()
print "Gravity evolve step done."
from_gravity_to_model.copy()
from_stellar_evolution_to_model.copy_attributes(["mass", "radius"])
particles.savepoint(time)
from_model_to_gravity.copy_attributes(["mass"])
total_energy_at_this_time \
= gravity.kinetic_energy + gravity.potential_energy
print_log(time, gravity, particles,
total_energy_at_t0, total_energy_at_this_time)
test_results_path = get_path_to_results()
output_file = os.path.join(test_results_path, "small.hdf5")
if os.path.exists(output_file):
os.remove(output_file)
storage = store.StoreHDF(output_file)
storage.store(particles)
gravity.stop()
stellar_evolution.stop()
plot_particles(particles, name_of_the_figure)
