def run_only_gravity(bodies, t_end):
Mtot_init = bodies.mass.sum()
time = [] | units.Myr
Lr25 = [] |units.parsec
Lr50 = [] |units.parsec
Lr75 = [] |units.parsec
converter = nbody_system.nbody_to_si(bodies.mass.sum(), 1|units.parsec)
gravity = ph4(converter)
gravity.particles.add_particles(bodies)
channel_from_gravity = gravity.particles.new_channel_to(bodies)
dt = 0.1|units.Myr
while True:
time.append(gravity.model_time)
Lr25.append(LagrangianRadii(gravity.particles)[5])
Lr50.append(LagrangianRadii(gravity.particles)[6])
Lr75.append(LagrangianRadii(gravity.particles)[7])
gravity.evolve_model(time[-1]+dt)
channel_from_gravity.copy_attributes(["x", "y", "z", "vx", "vy", "vz"])
print "G: T=", time[-1], "M=", bodies.mass.sum(), \
"(dM[SE]=", bodies.mass.sum()/Mtot_init, ")"
if time[-1] >= t_end:
break
gravity.stop()
return time, Lr25, Lr50, Lr75
def run_event_driven_gravity_and_stellar(bodies, t_end):
Mtot_init = bodies.mass.sum()
time = [] | units.Myr
Lr25 = [] |units.parsec
Lr50 = [] |units.parsec
Lr75 = [] |units.parsec
converter = nbody_system.nbody_to_si(bodies.mass.sum(), 1|units.parsec)
gravity = ph4(converter, number_of_workers=2)
gravity.particles.add_particles(bodies)
stellar = SSE()
stellar.parameters.metallicity = 0.02
stellar.particles.add_particle(bodies)
channel_from_gravity = gravity.particles.new_channel_to(
bodies, attributes=["mass", "x", "y", "z", "vx", "vy", "vz"])
channel_from_stellar = stellar.particles.new_channel_to(
bodies, attributes=["mass"])
channel_from_stellar_to_gravity = stellar.particles.new_channel_to(
gravity.particles, attributes=["mass"])
while True:
dt = 0.5*stellar.particles.time_step.min()
stellar.evolve_model(gravity.model_time + dt/2)
channel_from_stellar_to_gravity.copy()
dt = 0.5*stellar.particles.time_step.min()
gravity.evolve_model(stellar.model_time + dt)
channel_from_gravity.copy()
stellar.evolve_model(gravity.model_time)
channel_from_stellar.copy()
time.append(gravity.model_time)
Lr25.append(LagrangianRadii(gravity.particles)[5])
Lr50.append(LagrangianRadii(gravity.particles)[6])
Lr75.append(LagrangianRadii(gravity.particles)[7])
stellar.evolve_model()
print "GSE: T=", time[-1], "M=", bodies.mass.sum(), \
"(dM[SE]=", bodies.mass.sum()/Mtot_init, ")"
if time[-1] >= t_end:
break
gravity.stop()
stellar.stop()
return time, Lr25, Lr50, Lr75
def run_sequential_gravity_and_stellar(bodies, t_end):
Mtot_init = bodies.mass.sum()
time = [] | units.Myr
Lr25 = [] | units.parsec
Lr50 = [] | units.parsec
Lr75 = [] | units.parsec
converter = nbody_system.nbody_to_si(bodies.mass.sum(), 1 | units.parsec)
gravity = ph4(converter)
gravity.particles.add_particles(bodies)
channel_from_gravity = gravity.particles.new_channel_to(bodies)
channel_to_gravity = bodies.new_channel_to(gravity.particles)
stellar = SSE()
stellar.parameters.metallicity = 0.02
stellar.particles.add_particle(bodies)
channel_from_stellar = stellar.particles.new_channel_to(bodies)
dt = 0.1 | units.Myr
while True:
stellar.evolve_model(gravity.model_time + dt / 2)
channel_from_stellar.copy_attributes(["mass"])
channel_to_gravity.copy_attributes(["mass"])
gravity.evolve_model(gravity.model_time + dt)
channel_from_gravity.copy_attributes(["x", "y", "z", "vx", "vy", "vz"])
stellar.evolve_model(gravity.model_time + dt)
channel_from_stellar.copy_attributes(["mass"])
channel_to_gravity.copy_attributes(["mass"])
time.append(gravity.model_time)
Lr25.append(LagrangianRadii(gravity.particles)[5])
Lr50.append(LagrangianRadii(gravity.particles)[6])
Lr75.append(LagrangianRadii(gravity.particles)[7])
print("GS: T=", time[-1], "M=", bodies.mass.sum(), \
"(dM[SE]=", bodies.mass.sum()/Mtot_init, ")")
if time[-1] >= t_end:
break
gravity.stop()
stellar.stop()
return time, Lr25, Lr50, Lr75
def get_zones(stars):
stars.move_to_center()
from amuse.ext.LagrangianRadii import LagrangianRadii
massf = [0.25, 0.50, 0.75, 1.0]
lagrad = LagrangianRadii(stars, massf = massf)
for zi in lagrad:
print("R=", zi.in_(units.RSun))
center_of_mass = [0,0,0] | units.RSun #initial_stars.center_of_mass()
zoneA = stars.select(lambda r: (center_of_mass-r).length()<lagrad[0], ["position"])
zoneB = stars.select(lambda r: (center_of_mass-r).length()<lagrad[1], ["position"])
zoneC = stars.select(lambda r: (center_of_mass-r).length()<lagrad[2], ["position"])
zoneC -= zoneB
zoneB -= zoneA
zoneD = stars.select(lambda r: (center_of_mass-r).length()>lagrad[2], ["position"])
print("N=", len(zoneA), len(zoneB), len(zoneC), len(zoneD))
return (zoneA, zoneB, zoneC, zoneD)
def main(N=10,
W0=7.0,
t_end=10,
nsteps=10,
filename="gravity_stellar.hdf5",
Mmax=100,
Qvir=0.5):
t_end = t_end | nbody_system.time
dt = t_end / float(nsteps)
bodies = new_king_model(N, W0)
masses = new_powerlaw_mass_distribution(N,
mass_min=0.1 | units.MSun,
mass_max=10 | units.MSun,
alpha=-2.35)
masses /= masses.sum()
bodies.mass = masses | nbody_system.mass
bodies.radius = 0.001 | nbody_system.length
Mtot_init = 1 | nbody_system.mass
gravity = ph4(number_of_workers=4)
gravity.particles.add_particles(bodies)
bodies.scale_to_standard(virial_ratio=Qvir)
channel_from_gd_to_framework = gravity.particles.new_channel_to(bodies)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
Etot_init = gravity.kinetic_energy + gravity.potential_energy
Etot_prev = Etot_init
time = 0.0 | t_end.unit
Nenc = 0
dEk_enc = zero
dEp_enc = zero
t = []
rcore = []
MassFraction = [0.005, 0.01, 0.02, 0.05, 0.1, 0.25, 0.5, 0.75, 0.9, 1.0]
r50 = []
r90 = []
tcoll = []
rcoll = []
mcoll = []
while time < t_end:
RL = LagrangianRadii(gravity.particles, massf=MassFraction)
pos,coreradius,coredens = \
gravity.particles.densitycentre_coreradius_coredens()
print("Cluster at time=", time, "core_radius=", coreradius, \
"L_radii =", end=' ')
for rl in RL:
print(rl.number, " ", end=' ')
print("length")
t.append(time.number)
rcore.append(coreradius.number)
r50.append(RL[6].number)
r90.append(RL[8].number)
gravity.evolve_model(time + dt)
time = gravity.model_time
if stopping_condition.is_set():
Ek_enc = gravity.kinetic_energy
Ep_enc = gravity.potential_energy
print("At time=", time, "number of encounters=", \
len(stopping_condition.particles(0)))
for ci in range(len(stopping_condition.particles(0))):
particles_in_encounter = Particles(particles=[
stopping_condition.particles(0)[ci],
stopping_condition.particles(1)[ci]
])
particles_in_encounter = \
particles_in_encounter.get_intersecting_subset_in(bodies)
new_particle = merge_two_stars(bodies, particles_in_encounter,
gravity.model_time)
bodies.synchronize_to(gravity.particles)
Nenc += 1
RL = LagrangianRadii(gravity.particles, massf=MassFraction)
print("Resolve encounter number", Nenc)
pos,coreradius,coredens = \
gravity.particles.densitycentre_coreradius_coredens()
print("Collision at time=", time, new_particle.mass.sum(), \
new_particle.position.length(), "Nstars= ", len(bodies), \
"Ncoll=", Nenc, "core_radius=", coreradius, "L_radii=", end=' ')
for rl in RL:
print(rl.number, " ", end=' ')
print("length")
pos = new_particle[0].position.number
rc = math.sqrt(numpy.sum(pos**2))
mc = new_particle[0].mass.number
tcoll.append(time.number)
rcoll.append(rc)
mcoll.append(mc)
dEk_enc += Ek_enc - gravity.kinetic_energy
dEp_enc += Ep_enc - gravity.potential_energy
bodies.move_to_center()
channel_from_gd_to_framework.copy()
Ekin = gravity.kinetic_energy
Epot = gravity.potential_energy
Etot = Ekin + Epot
dE = Etot_prev - Etot
Mtot = bodies.mass.sum()
print("T=", time, end=' ')
print("M=", Mtot, "(dM[SE]=", Mtot / Mtot_init, ")", end=' ')
print("E=", Etot, "Q=", Ekin / Epot, end=' ')
print("dE=", (Etot_init - Etot) / Etot,
"ddE=", (Etot_prev - Etot) / Etot,
end=' ')
print("dE(enc)=", dEk_enc, dEp_enc)
Etot_init -= dE
Etot_prev = Etot
gravity.stop()
pyplot.figure(figsize=(8, 6))
pyplot.plot(t, rcore, 'b')
pyplot.plot(t, r50, 'r')
pyplot.plot(t, r90, 'y')
size = numpy.array(mcoll)
mmin = numpy.amin(size)
size = 2 + 15 * numpy.log10(size / mmin)
pyplot.scatter(tcoll, rcoll, c='g', s=size)
pyplot.xlabel('t [N-body]')
pyplot.ylabel('R [N-body]')
pyplot.yscale('log')
save_file = 'gravity_collision.png'
pyplot.savefig(save_file)
print('\nSaved figure in file', save_file, '\n')
pyplot.show()
def main(N=10,
W0=7.0,
t_end=10,
nsteps=10,
filename="gravity_stellar.hdf5",
Mmax=100,
Qvir=0.5):
t_end = t_end | nbody_system.time
dt = t_end / float(nsteps)
bodies = new_king_model(N, W0)
masses = new_powerlaw_mass_distribution(N,
mass_min=0.1 | units.MSun,
mass_max=10 | units.MSun,
alpha=-2.35)
masses /= masses.sum()
bodies.mass = masses | nbody_system.mass
"""
alpha1 = 2.35 + 1
factor = (pow(Mmax, alpha1) - 1.0 )
masses = (pow(1.0 + (factor * numpy.random.random(N)), 1.0 / alpha1))
masses = masses / masses.sum()
Mtot_init = masses.sum()
"""
bodies.radius = 0.001 | nbody_system.length
Mtot_init = 1 | nbody_system.mass
gravity = ph4(number_of_workers=4)
# gravity.parameters.timestep_parameter = 0.01
gravity.particles.add_particles(bodies)
bodies.scale_to_standard(virial_ratio=Qvir)
channel_from_gd_to_framework = gravity.particles.new_channel_to(bodies)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
Etot_init = gravity.kinetic_energy + gravity.potential_energy
Etot_prev = Etot_init
time = 0.0 | t_end.unit
Nenc = 0
dEk_enc = zero
dEp_enc = zero
while time < t_end:
RL = LagrangianRadii(gravity.particles)
pos, coreradius, coredens = gravity.particles.densitycentre_coreradius_coredens(
)
print "Cluster at time=", time, "core_radius=", coreradius, "L_radius=",
for rl in RL:
print rl.number, " ",
print "length"
gravity.evolve_model(time + dt)
time = gravity.model_time
if stopping_condition.is_set():
Ek_enc = gravity.kinetic_energy
Ep_enc = gravity.potential_energy
print "At time=", time, "number of encounters=", len(
stopping_condition.particles(0))
for ci in range(len(stopping_condition.particles(0))):
particles_in_encounter = Particles(particles=[
stopping_condition.particles(0)[ci],
stopping_condition.particles(1)[ci]
])
particles_in_encounter = particles_in_encounter.get_intersecting_subset_in(
bodies)
new_particle = merge_two_stars(bodies, particles_in_encounter,
gravity.model_time)
bodies.synchronize_to(gravity.particles)
Nenc += 1
RL = LagrangianRadii(gravity.particles)
print "Resolve encounter Number:", Nenc
pos, coreradius, coredens = gravity.particles.densitycentre_coreradius_coredens(
)
print "Collision at time=", time, new_particle.mass.sum(
), new_particle.position.length(), "Nstars= ", len(
bodies
), "Ncoll=", Nenc, "core_radius=", coreradius, "L_radius=",
for rl in RL:
print rl.number, " ",
print "length"
dEk_enc += Ek_enc - gravity.kinetic_energy
dEp_enc += Ep_enc - gravity.potential_energy
channel_from_gd_to_framework.copy()
# write_set_to_file(bodies.savepoint(time), filename, 'hdf5')
Ekin = gravity.kinetic_energy
Epot = gravity.potential_energy
Etot = Ekin + Epot
dE = Etot_prev - Etot
Mtot = bodies.mass.sum()
print "T=", time,
print "M=", Mtot, "(dM[SE]=", Mtot / Mtot_init, ")",
print "E= ", Etot, "Q= ", Ekin / Epot,
print "dE=", (Etot_init - Etot) / Etot, "ddE=", (Etot_prev -
Etot) / Etot,
print "dE(enc)=", dEk_enc, dEp_enc
Etot_init -= dE
Etot_prev = Etot
gravity.stop()
dEk_enc = zero
dEp_enc = zero
t = []
MassFraction = [0.005, 0.01, 0.02, 0.05, 0.1, 0.25, 0.5, 0.75, 0.9, 1.0]
r10 = []
r25 = []
r50 = []
r75 = []
tcoll = []
rcoll = []
mcoll = []
while time < t_end:
RL = LagrangianRadii(gravity.particles, massf=MassFraction)
pos,coreradius,coredens = \
gravity.particles.densitycentre_coreradius_coredens()
print "Cluster at time=", time, "core_radius=", coreradius, \
"L_radii =",
for rl in RL:
print rl.number, " ",
print "length"
t.append(time.number)
r10.append(RL[4].number)
r25.append(RL[5].number)
r50.append(RL[6].number)
r75.append(RL[7].number)
gravity.evolve_model(time + dt)