def test6(self):
print("Test 6: testing user interface (nbody units)")
numpy.random.seed(345672)
masses = new_salpeter_mass_distribution_nbody(1000)
self.assertEqual(len(masses), 1000)
self.assertAlmostEqual(masses.sum(), 1.0 | nbody_system.mass)
self.assertAlmostEqual(masses.mean(), 1.0 / 1000 | nbody_system.mass)
self.assertAlmostEqual(masses.amin(), 0.10017909529 / 0.334475937397 / 1000 | nbody_system.mass)
self.assertAlmostEqual(masses.amax(), 19.7132849297 / 0.334475937397 / 1000 | nbody_system.mass)
def test6(self):
print "Test 6: testing user interface (nbody units)"
numpy.random.seed(345672)
masses = new_salpeter_mass_distribution_nbody(1000)
self.assertEqual(len(masses), 1000)
self.assertAlmostEqual(masses.sum(), 1.0 | nbody_system.mass)
self.assertAlmostEqual(masses.mean(), 1.0 / 1000 | nbody_system.mass)
self.assertAlmostEqual(masses.amin(), 0.10017909529 / 0.334475937397 / 1000 | nbody_system.mass)
self.assertAlmostEqual(masses.amax(), 19.7132849297 / 0.334475937397 / 1000 | nbody_system.mass)
def new_cluster(number_of_stars=1000, radius=None):
"""
Return a new cluster of stars with the given radii and a salpeter mass
distribution.
"""
if radius is None:
radius = (0.5 / number_of_stars) | nbody_system.length
particles = new_plummer_model(number_of_stars)
particles.mass = new_salpeter_mass_distribution_nbody(number_of_stars)
particles.radius = radius
particles.move_to_center()
return particles
def new_cluster(number_of_stars=1000, radius=None):
"""
Return a new cluster of stars with the given radii and a salpeter mass
distribution.
"""
if radius is None:
radius = (0.5 / number_of_stars) | nbody_system.length
particles = new_plummer_model(number_of_stars)
particles.mass = new_salpeter_mass_distribution_nbody(number_of_stars)
particles.radius = radius
particles.move_to_center()
return particles
def test6(self):
print "Test all particle attributes using Hop - each different function creates its own instance of Hop"
numpy.random.seed(123)
nbody_plummer = new_plummer_sphere(100)
nbody_plummer.mass = new_salpeter_mass_distribution_nbody(100)
# Each different function creates its own instance of Hop
result = nbody_plummer.new_particle_from_cluster_core(reuse_hop=True)
result = nbody_plummer.bound_subset(G=nbody_system.G, reuse_hop=True)
result = nbody_plummer.mass_segregation_Gini_coefficient(reuse_hop=True)
result = nbody_plummer.LagrangianRadii(reuse_hop=True)
result = nbody_plummer.densitycentre_coreradius_coredens(reuse_hop=True)
converter = nbody_system.nbody_to_si(1.0|units.MSun, 1.0 | units.parsec)
si_plummer = ParticlesWithUnitsConverted(nbody_plummer, converter.as_converter_from_si_to_nbody())
functions_using_hop = [
si_plummer.new_particle_from_cluster_core,
si_plummer.bound_subset,
si_plummer.mass_segregation_Gini_coefficient,
si_plummer.LagrangianRadii,
si_plummer.densitycentre_coreradius_coredens
]
# Each fails since the Hop instance it tries to reuse has a different unit_converter
for function_using_hop in functions_using_hop:
self.assertRaises(ConvertArgumentsException, function_using_hop, unit_converter=converter,
expected_message="error while converting parameter 'mass', error: Cannot express kg in mass, the units do not have the same bases")
# Close all Hop instances:
nbody_results = []
nbody_results.append(nbody_plummer.new_particle_from_cluster_core(reuse_hop=False))
nbody_results.append(nbody_plummer.bound_subset(G=nbody_system.G, reuse_hop=False))
nbody_results.append(nbody_plummer.mass_segregation_Gini_coefficient(reuse_hop=False))
nbody_results.append(nbody_plummer.LagrangianRadii(reuse_hop=False))
nbody_results.append(nbody_plummer.densitycentre_coreradius_coredens(reuse_hop=False))
# Now it works, because the Hop instances were closed, and new ones will be instantiated
si_results = []
for function_using_hop in functions_using_hop:
si_results.append(function_using_hop(unit_converter=converter))
convert = converter.as_converter_from_si_to_nbody()
self.assertAlmostRelativeEqual(si_results[0].position,
ParticlesWithUnitsConverted(nbody_results[0].as_set(), convert)[0].position)
self.assertAlmostRelativeEqual(si_results[1].position,
ParticlesWithUnitsConverted(nbody_results[1], convert).position)
self.assertAlmostRelativeEqual(si_results[2], nbody_results[2], places=10)
self.assertAlmostRelativeEqual(si_results[3][0], convert.from_target_to_source(nbody_results[3][0]), places=10)
for in_si, in_nbody in zip(si_results[4], nbody_results[4]):
self.assertAlmostRelativeEqual(in_si, convert.from_target_to_source(in_nbody), places=10)
def run_ph4(infile=None,
number_of_stars=40,
end_time=10 | nbody_system.time,
delta_t=1 | nbody_system.time,
n_workers=1,
use_gpu=1,
gpu_worker=1,
accuracy_parameter=0.1,
softening_length=-1 | nbody_system.length,
manage_encounters=1,
random_seed=1234):
if random_seed <= 0:
numpy.random.seed()
random_seed = numpy.random.randint(1, pow(2, 31) - 1)
numpy.random.seed(random_seed)
print("random seed =", random_seed)
if infile != None: print("input file =", infile)
print("end_time =", end_time.number)
print("delta_t =", delta_t.number)
print("n_workers =", n_workers)
print("use_gpu =", use_gpu)
print("manage_encounters =", manage_encounters)
print("\ninitializing the gravity module")
sys.stdout.flush()
# Note that there are actually three GPU options to test:
#
# 1. use the GPU code and allow GPU use (default)
# 2. use the GPU code but disable GPU use (-g)
# 3. use the non-GPU code (-G)
if gpu_worker == 1:
try:
gravity = grav(number_of_workers=n_workers,
redirection="none",
mode="gpu")
except Exception as ex:
gravity = grav(number_of_workers=n_workers, redirection="none")
else:
gravity = grav(number_of_workers=n_workers, redirection="none")
gravity.initialize_code()
gravity.parameters.set_defaults()
#-----------------------------------------------------------------
if infile == None:
print("making a Plummer model")
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id + 1
print("setting particle masses and radii")
#stars.mass = (1.0 / number_of_stars) | nbody_system.mass
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
stars.radius = 0.02 | nbody_system.length
print("centering stars")
stars.move_to_center()
print("scaling stars to virial equilibrium")
stars.scale_to_standard(
smoothing_length_squared=gravity.parameters.epsilon_squared)
time = 0.0 | nbody_system.time
sys.stdout.flush()
else:
# Read the input data. Units are dynamical.
print("reading file", infile)
id = []
mass = []
pos = []
vel = []
f = open(infile, 'r')
count = 0
for line in f:
if len(line) > 0:
count += 1
cols = line.split()
if count == 1: snap = int(cols[0])
elif count == 2: number_of_stars = int(cols[0])
elif count == 3: time = float(cols[0]) | nbody_system.time
else:
if len(cols) >= 8:
id.append(int(cols[0]))
mass.append(float(cols[1]))
pos.append(
(float(cols[2]), float(cols[3]), float(cols[4])))
vel.append(
(float(cols[5]), float(cols[6]), float(cols[7])))
f.close()
stars = datamodel.Particles(number_of_stars)
stars.id = id
stars.mass = mass | nbody_system.mass
stars.position = pos | nbody_system.length
stars.velocity = vel | nbody_system.speed
stars.radius = 0. | nbody_system.length
# print "IDs:", stars.id.number
sys.stdout.flush()
#-----------------------------------------------------------------
if softening_length == -1 | nbody_system.length:
eps2 = 0.25*(float(number_of_stars))**(-0.666667) \
| nbody_system.length**2
else:
eps2 = softening_length * softening_length
gravity.parameters.timestep_parameter = accuracy_parameter
gravity.parameters.epsilon_squared = eps2
gravity.parameters.use_gpu = use_gpu
# gravity.parameters.manage_encounters = manage_encounters
print("adding particles")
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
print('')
print("number_of_stars =", number_of_stars)
print("evolving to time =", end_time.number, \
"in steps of", delta_t.number)
sys.stdout.flush()
E0 = print_log(time, gravity)
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
kep = Kepler(redirection="none")
kep.initialize_code()
multiples_code = multiples.Multiples(gravity, new_smalln, kep)
while time < end_time:
time += delta_t
multiples_code.evolve_model(time)
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
print_log(time, gravity, E0)
sys.stdout.flush()
print('')
gravity.stop()
def run_ph4(infile = None, outfile = None,
number_of_stars = 100, number_of_binaries = 0,
end_time = 10 | nbody_system.time,
delta_t = 1 | nbody_system.time,
n_workers = 1, use_gpu = 1, gpu_worker = 1,
salpeter = 0,
accuracy_parameter = 0.1,
softening_length = 0.0 | nbody_system.length,
manage_encounters = 1, random_seed = 1234):
if random_seed <= 0:
numpy.random.seed()
random_seed = numpy.random.randint(1, pow(2,31)-1)
numpy.random.seed(random_seed)
print "random seed =", random_seed
if infile != None: print "input file =", infile
print "end_time =", end_time.number
print "delta_t =", delta_t.number
print "n_workers =", n_workers
print "use_gpu =", use_gpu
print "manage_encounters =", manage_encounters
print "\ninitializing the gravity module"
sys.stdout.flush()
init_smalln()
# Note that there are actually three GPU options:
#
# 1. use the GPU code and allow GPU use (default)
# 2. use the GPU code but disable GPU use (-g)
# 3. use the non-GPU code (-G)
if gpu_worker == 1:
try:
gravity = grav(number_of_workers = n_workers,
redirection = "none", mode = "gpu")
except Exception as ex:
gravity = grav(number_of_workers = n_workers,
redirection = "none")
else:
gravity = grav(number_of_workers = n_workers,
redirection = "none")
gravity.initialize_code()
gravity.parameters.set_defaults()
#-----------------------------------------------------------------
if infile == None:
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id+1
print "setting particle masses and radii"
if salpeter == 0:
print 'equal masses'
total_mass = 1.0 | nbody_system.mass
scaled_mass = total_mass / number_of_stars
else:
print 'salpeter mass function'
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
print "centering stars"
stars.move_to_center()
print "scaling stars to virial equilibrium"
stars.scale_to_standard(smoothing_length_squared
= gravity.parameters.epsilon_squared)
else:
# Read the input data. Units are dynamical (sorry).
# Format: id mass pos[3] vel[3]
print "reading file", infile
id = []
mass = []
pos = []
vel = []
f = open(infile, 'r')
count = 0
for line in f:
if len(line) > 0:
count += 1
cols = line.split()
if count == 1: snap = int(cols[0])
elif count == 2: number_of_stars = int(cols[0])
elif count == 3: time = float(cols[0]) | nbody_system.time
else:
if len(cols) >= 8:
id.append(int(cols[0]))
mass.append(float(cols[1]))
pos.append((float(cols[2]),
float(cols[3]), float(cols[4])))
vel.append((float(cols[5]),
float(cols[6]), float(cols[7])))
f.close()
stars = datamodel.Particles(number_of_stars)
stars.id = id
stars.mass = mass | nbody_system.mass
stars.position = pos | nbody_system.length
stars.velocity = vel | nbody_system.speed
#stars.radius = 0. | nbody_system.length
total_mass = stars.mass.sum()
ke = pa.kinetic_energy(stars)
kT = ke/(1.5*number_of_stars)
if number_of_binaries > 0:
# Turn selected stars into binary components.
# Only tested for equal-mass case.
kep = Kepler(redirection = "none")
kep.initialize_code()
added_mass = 0.0 | nbody_system.mass
# Work with energies rather than semimajor axes.
Emin = 10*kT
Emax = 20*kT
ecc = 0.1
id_count = number_of_stars
nbin = 0
for i in range(0, number_of_stars,
number_of_stars/number_of_binaries):
# Star i is CM, becomes component, add other star at end.
nbin += 1
mass = stars[i].mass
new_mass = numpy.random.uniform()*mass # uniform q?
mbin = mass + new_mass
fac = new_mass/mbin
E = Emin + numpy.random.uniform()*(Emax-Emin)
a = 0.5*nbody_system.G*mass*new_mass/E
kep.initialize_from_elements(mbin, a, ecc)
dr = quantities.AdaptingVectorQuantity()
dr.extend(kep.get_separation_vector())
dv = quantities.AdaptingVectorQuantity()
dv.extend(kep.get_velocity_vector())
newstar = datamodel.Particles(1)
newstar.mass = new_mass
newstar.position = stars[i].position + (1-fac)*dr
newstar.velocity = stars[i].velocity + (1-fac)*dv
# stars[i].mass = mass
stars[i].position = stars[i].position - fac*dr
stars[i].velocity = stars[i].velocity - fac*dv
id_count += 1
newstar.id = id_count
stars.add_particles(newstar)
added_mass += new_mass
if nbin >= number_of_binaries: break
kep.stop()
print 'created', nbin, 'binaries'
sys.stdout.flush()
stars.mass = stars.mass * total_mass/(total_mass+added_mass)
number_of_stars += nbin
# Set dynamical radii (assuming virial equilibrium and standard
# units). Note that this choice should be refined, and updated
# as the system evolves. Probably the choice of radius should be
# made entirely in the multiples module. TODO. In these units,
# M = 1 and <v^2> = 0.5, so the mean 90-degree turnaround impact
# parameter is
#
# b_90 = G (m_1+m_2) / vrel^2
# = 2 <m> / 2<v^2>
# = 2 / N for equal masses
#
# Taking r_i = m_i / 2<v^2> = m_i in virial equilibrium means
# that, approximately, "contact" means a 90-degree deflection (r_1
# + r_2 = b_90). A more conservative choice with r_i less than
# this value will isolates encounters better, but also place more
# load on the large-N dynamical module.
stars.radius = stars.mass.number | nbody_system.length
time = 0.0 | nbody_system.time
# print "IDs:", stars.id.number
print "recentering stars"
stars.move_to_center()
sys.stdout.flush()
#-----------------------------------------------------------------
if softening_length < 0.0 | nbody_system.length:
# Use ~interparticle spacing. Assuming standard units here. TODO
eps2 = 0.25*(float(number_of_stars))**(-0.666667) \
| nbody_system.length**2
else:
eps2 = softening_length*softening_length
print 'softening length =', eps2.sqrt()
gravity.parameters.timestep_parameter = accuracy_parameter
gravity.parameters.epsilon_squared = eps2
gravity.parameters.use_gpu = use_gpu
# gravity.parameters.manage_encounters = manage_encounters
print ''
print "adding particles"
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
print ''
print "number_of_stars =", number_of_stars
print "evolving to time =", end_time.number, \
"in steps of", delta_t.number
sys.stdout.flush()
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
# Debugging: prevent the multiples code from being called.
if 0:
stopping_condition.disable()
print 'stopping condition disabled'
sys.stdout.flush()
# -----------------------------------------------------------------
# Create the coupled code and integrate the system to the desired
# time, managing interactions internally.
kep = init_kepler(stars[0], stars[1])
multiples_code = multiples.Multiples(gravity, new_smalln, kep)
multiples_code.neighbor_perturbation_limit = 0.1
#multiples_code.neighbor_distance_factor = 1.0
#multiples_code.neighbor_veto = False
#multiples_code.neighbor_distance_factor = 2.0
multiples_code.neighbor_veto = True
print ''
print 'multiples_code.initial_scale_factor =', \
multiples_code.initial_scale_factor
print 'multiples_code.neighbor_perturbation_limit =', \
multiples_code.neighbor_perturbation_limit
print 'multiples_code.neighbor_veto =', \
multiples_code.neighbor_veto
print 'multiples_code.final_scale_factor =', \
multiples_code.final_scale_factor
print 'multiples_code.initial_scatter_factor =', \
multiples_code.initial_scatter_factor
print 'multiples_code.final_scatter_factor =', \
multiples_code.final_scatter_factor
print 'multiples_code.retain_binary_apocenter =', \
multiples_code.retain_binary_apocenter
print 'multiples_code.wide_perturbation_limit =', \
multiples_code.wide_perturbation_limit
pre = "%%% "
E0,cpu0 = print_log(pre, time, multiples_code)
while time < end_time:
time += delta_t
multiples_code.evolve_model(time)
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
print_log(pre, time, multiples_code, E0, cpu0)
sys.stdout.flush()
#-----------------------------------------------------------------
if not outfile == None:
# Write data to a file.
f = open(outfile, 'w')
#--------------------------------------------------
# Need to save top-level stellar data and parameters.
# Need to save multiple data and parameters.
f.write('%.15g\n'%(time.number))
for s in multiples_code.stars: write_star(s, f)
#--------------------------------------------------
f.close()
print 'wrote file', outfile
print ''
gravity.stop()
def run_hacs(infile=None,
number_of_stars=128,
nmax=2048,
end_time=0.1 | nbody_system.time,
delta_t=0.125 | nbody_system.time,
dt_max=0.0625 | nbody_system.time,
n_ngb=16,
eta_irr=0.6,
eta_reg=0.1,
softening_length=0.0 | nbody_system.length):
if infile != None: print "input file =", infile
print "end_time =", end_time.number
print "nstars= ", number_of_stars,
print "nmax= ", nmax,
print "delta_t= ", delta_t.number
print "dt_max= ", dt_max.number
print "n_ngb= ", n_ngb,
print "eta_irr= ", eta_irr
print "eta_reg= ", eta_reg
print "eps2= ", softening_length.number**2
print "\ninitializing the gravity module"
sys.stdout.flush()
# gravity = grav(number_of_workers = 1, redirection = "none", mode='cpu')
gravity = grav(number_of_workers=1, redirection="none", mode='cpu')
gravity.initialize_code()
#-----------------------------------------------------------------
if infile == None:
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id + 1
print "setting particle masses and radii"
#stars.mass = (1.0 / number_of_stars) | nbody_system.mass
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
stars.radius = 0.0 | nbody_system.length
print "centering stars"
stars.move_to_center()
print "scaling stars to virial equilibrium"
stars.scale_to_standard(
smoothing_length_squared=gravity.parameters.eps2)
time = 0.0 | nbody_system.time
sys.stdout.flush()
else:
# Read the input data. Units are dynamical.
print "reading file", infile
id = []
mass = []
pos = []
vel = []
f = open(infile, 'r')
count = 0
for line in f:
if len(line) > 0:
count += 1
cols = line.split()
if count == 1: snap = int(cols[0])
elif count == 2: number_of_stars = int(cols[0])
elif count == 3: time = float(cols[0]) | nbody_system.time
else:
if len(cols) >= 8:
id.append(int(cols[0]))
mass.append(float(cols[1]))
pos.append(
(float(cols[2]), float(cols[3]), float(cols[4])))
vel.append(
(float(cols[5]), float(cols[6]), float(cols[7])))
f.close()
stars = datamodel.Particles(number_of_stars)
stars.id = id
print len(mass), len(pos), len(vel), len(id)
stars.mass = mass | nbody_system.mass
stars.position = pos | nbody_system.length
stars.velocity = vel | nbody_system.speed
stars.radius = 0. | nbody_system.length
nmax = 2 * len(mass)
# print "IDs:", stars.id.number
sys.stdout.flush()
#-----------------------------------------------------------------
gravity.parameters.nmax = nmax
gravity.parameters.dtmax = dt_max
# gravity.parameters.n_ngb = n_ngb;
gravity.parameters.eta_irr = eta_irr
gravity.parameters.eta_reg = eta_reg
gravity.parameters.eps2 = softening_length**2
gravity.commit_parameters()
print "adding particles"
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
print ''
print "number_of_stars =", number_of_stars
print "evolving to time =", end_time.number, \
"in steps of", delta_t.number
sys.stdout.flush()
E0 = print_log(time, gravity)
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
# stopping_condition.disable()
while time < end_time:
if (gravity.get_time() >= time):
time += delta_t
gravity.evolve_model(time)
# Ensure that the stars list is consistent with the internal
# data in the module.
ls = len(stars)
# Update the bookkeeping: synchronize stars with the module data.
# this breaks the code ...
channel.copy()
# Copy values from the module to the set in memory.
channel.copy_attribute("index_in_code", "id")
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
if stopping_condition.is_set():
star1 = stopping_condition.particles(0)[0]
star2 = stopping_condition.particles(1)[0]
gravity.synchronize_model()
print '\nstopping condition set at time', \
gravity.get_time().number,'for:\n'
print star1
print ''
print star2
print ''
gravity.particles.remove_particle(star1)
gravity.particles.remove_particle(star2)
gravity.recommit_particles()
print 'ls=', len(stars)
gravity.update_particle_set()
gravity.particles.synchronize_to(stars)
print 'ls=', len(stars)
if len(stars) != ls:
if 0:
print "stars:"
for s in stars:
print " ", s.id.number, s.mass.number, s.x.number, s.y.number, s.z.number
else:
print "number of stars =", len(stars)
sys.stdout.flush()
print_log(gravity.get_time(), gravity, E0)
sys.stdout.flush()
print ''
print_log(gravity.get_time(), gravity, E0)
sys.stdout.flush()
gravity.stop()
def make_nbody(number_of_stars=100,
time=0.0,
n_workers=1,
use_gpu=1,
gpu_worker=1,
salpeter=0,
delta_t=1.0 | nbody_system.time,
timestep_parameter=0.1,
softening_length=0.0 | nbody_system.length,
random_seed=1234):
# Make an N-body system, print out some statistics on it, and save
# it in a restart file. The restart file name is of the form
# 't=nnnn.n.xxx', where the default time is 0.0.
if random_seed <= 0:
numpy.random.seed()
random_seed = numpy.random.randint(1, pow(2, 31) - 1)
numpy.random.seed(random_seed)
print "random seed =", random_seed
init_smalln()
# Note that there are actually three GPU options:
#
# 1. use the GPU code and allow GPU use (default)
# 2. use the GPU code but disable GPU use (-g)
# 3. use the non-GPU code (-G)
if gpu_worker == 1:
try:
gravity = grav(number_of_workers=n_workers,
redirection="none",
mode="gpu")
except Exception as ex:
gravity = grav(number_of_workers=n_workers, redirection="none")
else:
gravity = grav(number_of_workers=n_workers, redirection="none")
gravity.initialize_code()
gravity.parameters.set_defaults()
#-----------------------------------------------------------------
# Make a standard N-body system.
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id + 1
print "setting particle masses and radii"
if salpeter == 0:
print 'equal masses'
total_mass = 1.0 | nbody_system.mass
scaled_mass = total_mass / number_of_stars
else:
print 'salpeter mass function'
mmin = 0.5 | nbody_system.mass
mmax = 10.0 | nbody_system.mass
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars,
mass_min=mmin,
mass_max=mmax)
stars.mass = scaled_mass
print "centering stars"
stars.move_to_center()
print "scaling stars to virial equilibrium"
stars.scale_to_standard(
smoothing_length_squared=gravity.parameters.epsilon_squared)
# Set dynamical radii (assuming virial equilibrium and standard
# units). Note that this choice should be refined, and updated
# as the system evolves. Probably the choice of radius should be
# made entirely in the multiples module. TODO. In these units,
# M = 1 and <v^2> = 0.5, so the mean 90-degree turnaround impact
# parameter is
#
# b_90 = G (m_1+m_2) / vrel^2
# = 2 <m> / 2<v^2>
# = 2 / N for equal masses
#
# Taking r_i = m_i / 2<v^2> = m_i in virial equilibrium means
# that, approximately, "contact" means a 90-degree deflection (r_1
# + r_2 = b_90). A more conservative choice with r_i less than
# this value will isolate encounters better, but also place more
# load on the large-N dynamical module.
stars.radius = 0.5 * stars.mass.number | nbody_system.length
time = 0.0 | nbody_system.time
# print "IDs:", stars.id.number
print "recentering stars"
stars.move_to_center()
sys.stdout.flush()
#-----------------------------------------------------------------
if softening_length < 0.0 | nbody_system.length:
# Use ~interparticle spacing. Assuming standard units here. TODO
softening_length = 0.5*float(number_of_stars)**(-0.3333333) \
| nbody_system.length
print 'softening length =', softening_length
gravity.parameters.timestep_parameter = timestep_parameter
gravity.parameters.epsilon_squared = softening_length * softening_length
gravity.parameters.use_gpu = use_gpu
print ''
print "adding particles"
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
print ''
print "number_of_stars =", number_of_stars
sys.stdout.flush()
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
# -----------------------------------------------------------------
# Create the coupled code and integrate the system to the desired
# time, managing interactions internally.
kep = init_kepler(stars[0], stars[1])
multiples_code = multiples.Multiples(gravity, new_smalln, kep)
multiples_code.neighbor_perturbation_limit = 0.1
multiples_code.neighbor_veto = True
print ''
print 'multiples_code.initial_scale_factor =', \
multiples_code.initial_scale_factor
print 'multiples_code.neighbor_perturbation_limit =', \
multiples_code.neighbor_perturbation_limit
print 'multiples_code.neighbor_veto =', \
multiples_code.neighbor_veto
print 'multiples_code.final_scale_factor =', \
multiples_code.final_scale_factor
print 'multiples_code.initial_scatter_factor =', \
multiples_code.initial_scatter_factor
print 'multiples_code.final_scatter_factor =', \
multiples_code.final_scatter_factor
print 'multiples_code.retain_binary_apocenter =', \
multiples_code.retain_binary_apocenter
print 'multiples_code.wide_perturbation_limit =', \
multiples_code.wide_perturbation_limit
# Take a dummy step, just in case...
multiples_code.evolve_model(time)
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
pre = "%%% "
E0, cpu0 = print_log(pre, time, multiples_code)
sys.stdout.flush()
# file = 't='+'{:07.2f}'.format(time.number) # fails in Python 2.6
file = 't=%07.2f' % time.number
write_state_to_file(time, stars, gravity, multiples_code, file, delta_t,
E0, cpu0)
tree_copy = multiples_code.root_to_tree.copy()
del multiples_code
sys.stdout.flush()
gravity.stop()
kep.stop()
stop_smalln()
print ''
def run_multiples(infile = None,
number_of_stars = 64,
nmax = 2048,
end_time = 0.1 | nbody_system.time,
delta_t = 0.125 | nbody_system.time,
dt_max = 0.0625 | nbody_system.time,
n_ngb = 16,
eta_irr = 0.6,
eta_reg = 0.1,
softening_length = 0.0 | nbody_system.length,
random_seed = 1234):
if infile != None: print "input file =", infile
print "end_time =", end_time.number
print "nstars= ", number_of_stars,
print "nmax= ", nmax,
print "delta_t= ", delta_t.number
print "dt_max= ", dt_max.number
print "n_ngb= ", n_ngb,
print "eta_irr= ", eta_irr
print "eta_reg= ", eta_reg
print "eps2= ", softening_length.number**2
print "\ninitializing the gravity module"
sys.stdout.flush()
if random_seed <= 0:
numpy.random.seed()
random_seed = numpy.random.randint(1, pow(2,31)-1)
numpy.random.seed(random_seed)
print "random seed =", random_seed
# Note that there are actually three GPU options to test:
#
# 1. use the GPU code and allow GPU use (default)
# 2. use the GPU code but disable GPU use (-g)
# 3. use the non-GPU code (-G)
gravity = grav(number_of_workers = 1, debugger="none", redirection = "none")
gravity.initialize_code()
#-----------------------------------------------------------------
if infile == None:
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id+1
print "setting particle masses and radii"
#stars.mass = (1.0 / number_of_stars) | nbody_system.mass
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
stars.radius = 0.0 | nbody_system.length
print "centering stars"
stars.move_to_center()
print "scaling stars to virial equilibrium"
stars.scale_to_standard(smoothing_length_squared
= 0 | nbody_system.length ** 2)
time = 0.0 | nbody_system.time
sys.stdout.flush()
else:
# Read the input data. Units are dynamical.
print "reading file", infile; sys.stdout.flush()
id = []
mass = []
pos = []
vel = []
f = open(infile, 'r')
count = 0
for line in f:
if len(line) > 0:
count += 1
cols = line.split()
if count == 1: snap = int(cols[0])
elif count == 2: number_of_stars = int(cols[0])
elif count == 3: time = float(cols[0]) | nbody_system.time
else:
if len(cols) >= 8:
# id.append(int(cols[0]))
id.append(count)
mass.append(float(cols[1]))
pos.append((float(cols[2]),
float(cols[3]), float(cols[4])))
vel.append((float(cols[5]),
float(cols[6]), float(cols[7])))
f.close()
stars = datamodel.Particles(number_of_stars)
stars.id = id
stars.mass = mass | nbody_system.mass
stars.position = pos | nbody_system.length
stars.velocity = vel | nbody_system.speed
stars.radius = 0. | nbody_system.length
nmax = 2*len(mass)
# print "IDs:", stars.id.number
sys.stdout.flush()
global root_index
root_index = len(stars) + 10000
#-----------------------------------------------------------------
gravity.parameters.nmax = nmax;
gravity.parameters.dtmax = dt_max;
# gravity.parameters.n_ngb = n_ngb;
gravity.parameters.eta_irr = eta_irr;
gravity.parameters.eta_reg = eta_reg;
gravity.parameters.eps2 = softening_length**2
gravity.commit_parameters();
print "adding particles"
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
print ''
print "number_of_stars =", number_of_stars
print "evolving to time =", end_time.number, \
"in steps of", delta_t.number
sys.stdout.flush()
E0 = print_log('hacs64', gravity)
dEmult = 0.0
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
#stopping_condition.enable()
# Tree structure on the stars dataset:
stars.child1 = 0 | units.object_key
stars.child2 = 0 | units.object_key
while time < end_time:
time += delta_t
while gravity.get_time() < time:
gravity.evolve_model(time)
if stopping_condition.is_set():
star1 = stopping_condition.particles(0)[0]
star2 = stopping_condition.particles(1)[0]
print '\n--------------------------------------------------'
print 'stopping condition set at time', \
gravity.get_time().number
E = print_log('hacs64', gravity, E0)
print 'dEmult =', dEmult, 'dE =', (E-E0).number-dEmult
# channel.copy() # need other stars to be current in memory
# print_energies(stars)
# Synchronize everything for now. Later we will just
# synchronize neighbors if gravity supports that. TODO
gravity.synchronize_model()
gravity.particles.synchronize_to(stars)
dEmult += manage_encounter(star1, star2, stars,
gravity.particles)
# Recommit reinitializes all particles (and redundant
# here, since done automatically). Later we will just
# recommit and reinitialize a list if gravity supports
# it. TODO
gravity.recommit_particles()
E = print_log('hacs64', gravity, E0)
print 'dEmult =', dEmult, 'dE =', (E-E0).number-dEmult
print '\n--------------------------------------------------'
ls = len(stars)
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
if len(stars) != ls:
if 0:
print "stars:"
for s in stars:
print " ", s.id.number, s.mass.number, \
s.x.number, s.y.number, s.z.number
else:
print "number of stars =", len(stars)
sys.stdout.flush()
E = print_log('hacs64', gravity, E0)
print 'dEmult =', dEmult, 'dE =', (E-E0).number-dEmult
print ''
gravity.stop()
def run_smallN(infile=None,
number_of_stars=10,
end_time=10 | nbody_system.time,
delta_t=1 | nbody_system.time,
accuracy_parameter=0.1):
if infile != None: print "input file =", infile
print "end_time =", end_time.number
print "delta_t =", delta_t.number
print "\ninitializing the gravity module"
sys.stdout.flush()
gravity = grav(redirection="none")
gravity.initialize_code()
gravity.parameters.set_defaults()
#-----------------------------------------------------------------
if infile == None:
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id + 1
print "setting particle masses and radii"
#stars.mass = (1.0 / number_of_stars) | nbody_system.mass
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
stars.radius = 0.0 | nbody_system.length
print "centering stars"
stars.move_to_center()
print "scaling stars to virial equilibrium"
stars.scale_to_standard(smoothing_length_squared = 0 \
| nbody_system.length*nbody_system.length)
time = 0.0 | nbody_system.time
sys.stdout.flush()
else:
# Read the input data. Units are dynamical.
print "reading file", infile
id = []
mass = []
pos = []
vel = []
f = open(infile, 'r')
count = 0
for line in f:
if len(line) > 0:
count += 1
cols = line.split()
if count == 1: snap = int(cols[0])
elif count == 2: number_of_stars = int(cols[0])
elif count == 3: time = float(cols[0]) | nbody_system.time
else:
if len(cols) >= 8:
id.append(int(cols[0]))
mass.append(float(cols[1]))
pos.append(
(float(cols[2]), float(cols[3]), float(cols[4])))
vel.append(
(float(cols[5]), float(cols[6]), float(cols[7])))
f.close()
stars = datamodel.Particles(number_of_stars)
stars.id = id
stars.mass = mass | nbody_system.mass
stars.position = pos | nbody_system.length
stars.velocity = vel | nbody_system.speed
stars.radius = 0. | nbody_system.length
# print "IDs:", stars.id.number
sys.stdout.flush()
#-----------------------------------------------------------------
gravity.parameters.timestep_parameter = accuracy_parameter
print "adding particles"
# print stars
sys.stdout.flush()
gravity.parameters.begin_time = time
gravity.particles.add_particles(stars)
print "committing particles"
gravity.commit_particles()
print ''
print "number_of_stars =", number_of_stars
print "evolving to time =", end_time.number, \
"in steps of", delta_t.number
sys.stdout.flush()
E0 = print_log(time, gravity)
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
while time < end_time:
time += delta_t
#gravity.parameters.outfile = 'abc'
gravity.evolve_model(time)
# Ensure that the stars list is consistent with the internal
# data in the module.
ls = len(stars)
# Update the bookkeeping: synchronize stars with the module data.
try:
gravity.update_particle_set()
gravity.particles.synchronize_to(stars)
except:
pass
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
if len(stars) != ls:
if 0:
print "stars:"
for s in stars:
print " ", s.id.number, s.mass.number, \
s.x.number, s.y.number, s.z.number
else:
print "number of stars =", len(stars)
sys.stdout.flush()
print_log(time, gravity, E0)
over = gravity.is_over()
if over:
gravity.update_particle_tree()
gravity.update_particle_set()
gravity.particles.synchronize_to(stars)
channel.copy()
channel.copy_attribute("index_in_code", "id")
print "binaries:"
x = trees.BinaryTreesOnAParticleSet(stars, "child1", "child2")
roots = list(x.iter_roots())
for r in roots:
for level, particle in r.iter_levels():
print ' ' * level, int(particle.id),
if not particle.child1 is None:
m, a, e = get_binary_elements(particle)
print ' (', m, a, e, ')'
else:
print ''
break
sys.stdout.flush()
if not over:
print '\ninteraction is not over'
gravity.stop()
def run_ph4(options,
time=None,
stars=None,
mc_root_to_tree=None,
randomize=True):
infile = options.infile
outfile = options.outfile
restart_file = options.restart_file
number_of_stars = options.N
number_of_binaries = options.Nbin
end_time = options.t_end | nbody_system.time
delta_t = options.delta_t | nbody_system.time
n_workers = options.n_workers
use_gpu = options.use_gpu
gpu_worker = options.gpu_worker
salpeter = options.salpeter
accuracy_parameter = options.accuracy_parameter
softening_length = options.softening_length | nbody_system.length
manage_encounters = options.manage_encounters
random_seed = options.random_seed
if randomize:
if random_seed <= 0:
numpy.random.seed()
random_seed = numpy.random.randint(1, pow(2, 31) - 1)
numpy.random.seed(random_seed)
print "random seed =", random_seed
if infile is not None: print "input file =", infile
if restart_file is not None: print "restart file =", restart_file
if restart_file is not None and infile is not None:
print "restart file overrides input file"
print "end_time =", end_time.number
print "delta_t =", delta_t.number
print "n_workers =", n_workers
print "use_gpu =", use_gpu
print "manage_encounters =", manage_encounters
print "n =", number_of_stars
print "nbin=", number_of_binaries
print "\ninitializing the gravity module"
sys.stdout.flush()
init_smalln()
# Note that there are actually three GPU options:
#
# 1. use the GPU code and allow GPU use (default)
# 2. use the GPU code but disable GPU use (-g)
# 3. use the non-GPU code (-G)
if gpu_worker == 1:
try:
#gravity = GravityModule(number_of_workers = n_workers,
# redirection = "xterm")
gravity = GravityModule(number_of_workers=n_workers,
redirection="none",
mode="gpu")
except Exception as ex:
gravity = GravityModule(number_of_workers=n_workers,
redirection="none")
else:
gravity = GravityModule(number_of_workers=n_workers,
redirection="none")
gravity.initialize_code()
gravity.parameters.set_defaults()
if softening_length < 0.0 | nbody_system.length:
# Use ~interparticle spacing. Assuming standard units here. TODO
eps2 = 0.25*(float(number_of_stars))**(-0.666667) \
| nbody_system.length**2
else:
eps2 = softening_length * softening_length
print 'softening length =', eps2.sqrt()
gravity.parameters.timestep_parameter = accuracy_parameter
gravity.parameters.epsilon_squared = eps2
gravity.parameters.use_gpu = use_gpu
kep = Kepler(redirection="none")
kep.initialize_code()
multiples_code = None
Xtra = numpy.zeros(2)
#-----------------------------------------------------------------
if (restart_file is None
or not os.path.exists(restart_file + ".stars.hdf5")
) and infile is None and stars is None:
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id + 1
print "setting particle masses and radii"
if salpeter == 0:
print 'equal masses'
total_mass = 1.0 | nbody_system.mass
scaled_mass = total_mass / number_of_stars
else:
print 'salpeter mass function'
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
print "centering stars"
stars.move_to_center()
print "scaling stars to virial equilibrium"
stars.scale_to_standard(
smoothing_length_squared=gravity.parameters.epsilon_squared)
time = 0.0 | nbody_system.time
total_mass = stars.mass.sum()
ke = pa.kinetic_energy(stars)
kT = ke / (1.5 * number_of_stars)
# Set dynamical radii (assuming virial equilibrium and standard
# units). Note that this choice should be refined, and updated
# as the system evolves. Probably the choice of radius should be
# made entirely in the multiples module. TODO. In these units,
# M = 1 and <v^2> = 0.5, so the mean 90-degree turnaround impact
# parameter is
#
# b_90 = G (m_1+m_2) / vrel^2
# = 2 <m> / 2<v^2>
# = 2 / N for equal masses
#
# Taking r_i = m_i / 2<v^2> = m_i in virial equilibrium means
# that, approximately, "contact" means a 90-degree deflection (r_1
# + r_2 = b_90). A more conservative choice with r_i less than
# this value will isolates encounters better, but also place more
# load on the large-N dynamical module.
stars.radius = stars.mass.number | nbody_system.length
if number_of_binaries > 0:
# Turn selected stars into binary components.
# Only tested for equal-mass case.
added_mass = 0.0 | nbody_system.mass
# Work with energies rather than semimajor axes.
Emin = 10 * kT
Emax = 20 * kT
ecc = 0.1
id_count = number_of_stars
nbin = 0
for i in range(0, number_of_stars,
number_of_stars / number_of_binaries):
# Star i is CM, becomes component, add other star at end.
nbin += 1
mass = stars[i].mass
#new_mass = numpy.random.uniform()*mass # uniform q?
new_mass = mass # uniform q?
mbin = mass + new_mass
fac = new_mass / mbin
E = Emin + numpy.random.uniform() * (Emax - Emin)
a = 0.5 * nbody_system.G * mass * new_mass / E
kep.initialize_from_elements(mbin, a, ecc)
dr = quantities.AdaptingVectorQuantity()
dr.extend(kep.get_separation_vector())
dv = quantities.AdaptingVectorQuantity()
dv.extend(kep.get_velocity_vector())
newstar = datamodel.Particles(1)
newstar.mass = new_mass
newstar.position = stars[i].position + (1 - fac) * dr
newstar.velocity = stars[i].velocity + (1 - fac) * dv
newstar.radius = newstar.mass.number | nbody_system.length
#newstar.radius = 3.0*stars[i].radius # HACK: try to force collision
# stars[i].mass = mass
stars[i].position = stars[i].position - fac * dr
stars[i].velocity = stars[i].velocity - fac * dv
id_count += 1
newstar.id = id_count
stars.add_particles(newstar)
added_mass += new_mass
if nbin >= number_of_binaries: break
kep.stop()
print 'created', nbin, 'binaries'
sys.stdout.flush()
stars.mass = stars.mass * total_mass / (total_mass + added_mass)
number_of_stars += nbin
Xtra = numpy.zeros(2)
print "recentering stars"
stars.move_to_center()
sys.stdout.flush()
stars.savepoint(time)
print ''
print "adding particles"
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
else:
print "Restart detected. Loading parameters from restart."
new_end = options.t_end
stars, time, multiples_code, Xtra = MRest.read_state_from_file(
restart_file, gravity, new_smalln, kep)
options.t_end = new_end
total_mass = stars.mass.sum()
ke = pa.kinetic_energy(stars)
kT = ke / (1.5 * number_of_stars)
# print "IDs:", stars.id.number
print ''
print "number_of_stars =", number_of_stars
print "evolving to time =", end_time.number, \
"in steps of", delta_t.number
sys.stdout.flush()
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
# -----------------------------------------------------------------
# Create the coupled code and integrate the system to the desired
# time, managing interactions internally.
kep = init_kepler(stars[0], stars[1])
if not multiples_code:
multiples_code = multiples.Multiples(gravity, new_smalln, kep)
multiples_code.neighbor_distance_factor = 1.0
multiples_code.neighbor_veto = True
#multiples_code.neighbor_distance_factor = 2.0
#multiples_code.neighbor_veto = True
multiples_code.retain_binary_apocenter = False
print ''
print 'multiples_code.initial_scale_factor =', \
multiples_code.initial_scale_factor
print 'multiples_code.neighbor_distance_factor =', \
multiples_code.neighbor_distance_factor
print 'multiples_code.neighbor_veto =', \
multiples_code.neighbor_veto
print 'multiples_code.final_scale_factor =', \
multiples_code.final_scale_factor
print 'multiples_code.initial_scatter_factor =', \
multiples_code.initial_scatter_factor
print 'multiples_code.final_scatter_factor =', \
multiples_code.final_scatter_factor
print 'multiples_code.retain_binary_apocenter =', \
multiples_code.retain_binary_apocenter
# if mc_root_to_tree is not None:
# multiples_code.root_to_tree = mc_root_to_tree
# print 'multiples code re-loaded with binary trees snapshot'
pre = "%%% "
E0, cpu0 = print_log(pre, time, multiples_code)
while time < end_time:
time += delta_t
multiples_code.evolve_model(time)
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
print_log(pre, time, multiples_code, E0, cpu0)
stars.savepoint(time)
MRest.write_state_to_file(time,
stars,
gravity,
multiples_code,
options.restart_file,
Xtra,
backup=1)
sys.stdout.flush()
#-----------------------------------------------------------------
if not outfile is None:
# Write data to a file.
f = open(outfile, 'w')
#--------------------------------------------------
# Need to save top-level stellar data and parameters.
# Need to save multiple data and parameters.
f.write('%.15g\n' % time.number)
for s in multiples_code.stars:
write_star(s, f)
#--------------------------------------------------
f.close()
print 'wrote file', outfile
print ''
gravity.stop()
def run_multiples(infile=None,
number_of_stars=64,
nmax=2048,
end_time=0.1 | nbody_system.time,
delta_t=0.125 | nbody_system.time,
dt_max=0.0625 | nbody_system.time,
n_ngb=16,
eta_irr=0.6,
eta_reg=0.1,
softening_length=0.0 | nbody_system.length,
random_seed=1234):
if infile != None: print("input file =", infile)
print("end_time =", end_time.number)
print("nstars= ", number_of_stars, end=' ')
print("nmax= ", nmax, end=' ')
print("delta_t= ", delta_t.number)
print("dt_max= ", dt_max.number)
print("n_ngb= ", n_ngb, end=' ')
print("eta_irr= ", eta_irr)
print("eta_reg= ", eta_reg)
print("eps2= ", softening_length.number**2)
print("\ninitializing the gravity module")
sys.stdout.flush()
if random_seed <= 0:
numpy.random.seed()
random_seed = numpy.random.randint(1, pow(2, 31) - 1)
numpy.random.seed(random_seed)
print("random seed =", random_seed)
# Note that there are actually three GPU options to test:
#
# 1. use the GPU code and allow GPU use (default)
# 2. use the GPU code but disable GPU use (-g)
# 3. use the non-GPU code (-G)
gravity = grav(number_of_workers=1, debugger="none", redirection="none")
gravity.initialize_code()
#-----------------------------------------------------------------
if infile == None:
print("making a Plummer model")
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id + 1
print("setting particle masses and radii")
#stars.mass = (1.0 / number_of_stars) | nbody_system.mass
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
stars.radius = 0.0 | nbody_system.length
print("centering stars")
stars.move_to_center()
print("scaling stars to virial equilibrium")
stars.scale_to_standard(smoothing_length_squared=0
| nbody_system.length**2)
time = 0.0 | nbody_system.time
sys.stdout.flush()
else:
# Read the input data. Units are dynamical.
print("reading file", infile)
sys.stdout.flush()
id = []
mass = []
pos = []
vel = []
f = open(infile, 'r')
count = 0
for line in f:
if len(line) > 0:
count += 1
cols = line.split()
if count == 1: snap = int(cols[0])
elif count == 2: number_of_stars = int(cols[0])
elif count == 3: time = float(cols[0]) | nbody_system.time
else:
if len(cols) >= 8:
# id.append(int(cols[0]))
id.append(count)
mass.append(float(cols[1]))
pos.append(
(float(cols[2]), float(cols[3]), float(cols[4])))
vel.append(
(float(cols[5]), float(cols[6]), float(cols[7])))
f.close()
stars = datamodel.Particles(number_of_stars)
stars.id = id
stars.mass = mass | nbody_system.mass
stars.position = pos | nbody_system.length
stars.velocity = vel | nbody_system.speed
stars.radius = 0. | nbody_system.length
nmax = 2 * len(mass)
# print "IDs:", stars.id.number
sys.stdout.flush()
global root_index
root_index = len(stars) + 10000
#-----------------------------------------------------------------
gravity.parameters.nmax = nmax
gravity.parameters.dtmax = dt_max
# gravity.parameters.n_ngb = n_ngb;
gravity.parameters.eta_irr = eta_irr
gravity.parameters.eta_reg = eta_reg
gravity.parameters.eps2 = softening_length**2
gravity.commit_parameters()
print("adding particles")
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
print('')
print("number_of_stars =", number_of_stars)
print("evolving to time =", end_time.number, \
"in steps of", delta_t.number)
sys.stdout.flush()
E0 = print_log('hacs64', gravity)
dEmult = 0.0
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
#stopping_condition.enable()
# Tree structure on the stars dataset:
stars.child1 = 0 | units.object_key
stars.child2 = 0 | units.object_key
while time < end_time:
time += delta_t
while gravity.get_time() < time:
gravity.evolve_model(time)
if stopping_condition.is_set():
star1 = stopping_condition.particles(0)[0]
star2 = stopping_condition.particles(1)[0]
print('\n--------------------------------------------------')
print('stopping condition set at time', \
gravity.get_time().number)
E = print_log('hacs64', gravity, E0)
print('dEmult =', dEmult, 'dE =', (E - E0).number - dEmult)
# channel.copy() # need other stars to be current in memory
# print_energies(stars)
# Synchronize everything for now. Later we will just
# synchronize neighbors if gravity supports that. TODO
gravity.synchronize_model()
gravity.particles.synchronize_to(stars)
dEmult += manage_encounter(star1, star2, stars,
gravity.particles)
# Recommit reinitializes all particles (and redundant
# here, since done automatically). Later we will just
# recommit and reinitialize a list if gravity supports
# it. TODO
gravity.recommit_particles()
E = print_log('hacs64', gravity, E0)
print('dEmult =', dEmult, 'dE =', (E - E0).number - dEmult)
print('\n--------------------------------------------------')
ls = len(stars)
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
if len(stars) != ls:
if 0:
print("stars:")
for s in stars:
print(" ", s.id.number, s.mass.number, \
s.x.number, s.y.number, s.z.number)
else:
print("number of stars =", len(stars))
sys.stdout.flush()
E = print_log('hacs64', gravity, E0)
print('dEmult =', dEmult, 'dE =', (E - E0).number - dEmult)
print('')
gravity.stop()
def run_ph4(infile = None, number_of_stars = 40,
end_time = 10 | nbody_system.time,
delta_t = 1 | nbody_system.time,
n_workers = 1, use_gpu = 1, gpu_worker = 1, gpu_id = -1,
accuracy_parameter = 0.1,
softening_length = -1 | nbody_system.length,
manage_encounters = 1):
if infile != None: print "input file =", infile
print "end_time =", end_time.number
print "delta_t =", delta_t.number
print "n_workers =", n_workers
print "use_gpu =", use_gpu
print "manage_encounters =", manage_encounters
print "initializing the gravity module"
sys.stdout.flush()
# Note that there are actually really three GPU options to test:
#
# 1. use the GPU code and allow GPU use (default)
# 2. use the GPU code but disable GPU use (-g)
# 3. use the non-GPU code (-G)
#print "1"; sys.stdout.flush()
gpu = 0
if gpu_worker == 1:
try:
gravity = grav(number_of_workers = n_workers,
redirection = "none", mode = "gpu")
# debugger='valgrind')
gpu = 1
except Exception as ex:
print \
'*** GPU worker code not found. Reverting to non-GPU code. ***'
gpu = 0
if gpu == 0:
gravity = grav(number_of_workers = n_workers,
redirection = "none")
# debugger='valgrind')
#print "2"; sys.stdout.flush()
gravity.initialize_code()
#print "3"; sys.stdout.flush()
gravity.parameters.set_defaults()
gravity.parameters.gpu_id = gpu_id
#-----------------------------------------------------------------
#print "4"; sys.stdout.flush()
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id+1
print "setting particle masses and radii"
stars.mass = (1.0 / number_of_stars) | nbody_system.mass
if 0:
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
stars.radius = 0.0 | nbody_system.length
print "centering stars"
stars.move_to_center()
if 0:
print "scaling stars to virial equilibrium"
stars.scale_to_standard(smoothing_length_squared
= gravity.parameters.epsilon_squared)
time = 0.0 | nbody_system.time
sys.stdout.flush()
#-----------------------------------------------------------------
#print "5"; sys.stdout.flush()
if softening_length == -1 | nbody_system.length:
eps2 = 0.25*(float(number_of_stars))**(-0.666667) \
| nbody_system.length**2
else:
eps2 = softening_length*softening_length
#print "6"; sys.stdout.flush()
gravity.parameters.timestep_parameter = accuracy_parameter
gravity.parameters.epsilon_squared = eps2
gravity.parameters.use_gpu = use_gpu
gravity.parameters.manage_encounters = manage_encounters
print "adding particles"
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
print ''
print "number_of_stars =", number_of_stars
sys.stdout.flush()
E0,cpu0,wall0 = print_log('', time, gravity)
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
#-----------------------------------------------------------------
cpu0 = cputime()
t0 = 0.
pi = math.pi
times = [1., 2., pi, 4*pi/3, 5., 2*pi, 2*pi + pi/100,
2*pi + pi/5, 7., 8., 3*pi, 10.]
gravity.parameters.force_sync = 1 # stays set until explicitly unset
for t in times:
time = t|nbody_system.time
print "\nEvolving to time", time
sys.stdout.flush()
gravity.parameters.block_steps = 0
gravity.parameters.total_steps = 0
gravity.evolve_model(time)
dt = t - t0
t0 = t
cpu = cputime()
dcpu = cpu - cpu0
cpu0 = cpu
# Ensure that the stars list is consistent with the internal
# data in the module.
ls = len(stars)
# Update the bookkeeping: synchronize stars with the module data.
try:
gravity.update_particle_set()
gravity.particles.synchronize_to(stars)
except:
pass
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
if stopping_condition.is_set():
star1 = stopping_condition.particles(0)[0]
star2 = stopping_condition.particles(1)[0]
print '\nstopping condition set at time', \
gravity.get_time().number,'for:\n'
print star1
print ''
print star2
print ''
raise Exception("no encounter handling")
if len(stars) != ls:
if 0:
print "stars:"
for s in stars:
print " ", s.id.number, s.mass.number, \
s.x.number, s.y.number, s.z.number
else:
print "number of stars =", len(stars)
sys.stdout.flush()
print_log('', time, gravity, E0, cpu0, wall0)
print '@@@'
print '@@@ t =', time.number, ' dt =', dt
print '@@@ sync_time =', gravity.parameters.sync_time.number
print '@@@ dcpu/dt =', dcpu/dt
nb = gravity.parameters.block_steps
ns = gravity.parameters.total_steps
print '@@@ d(block_steps) =', nb, ' #/dt =', nb/dt
print '@@@ d(total steps) =', ns, ' #/dt =', ns/dt
#print stars
sys.stdout.flush()
#-----------------------------------------------------------------
print ''
gravity.stop()
def run_ph4(infile = None, number_of_stars = 40,
end_time = 10 | nbody_system.time,
delta_t = 1 | nbody_system.time,
n_workers = 1, use_gpu = 1, gpu_worker = 1,
accuracy_parameter = 0.1,
softening_length = -1 | nbody_system.length,
manage_encounters = 1, random_seed = 1234):
if random_seed <= 0:
numpy.random.seed()
random_seed = numpy.random.randint(1, pow(2,31)-1)
numpy.random.seed(random_seed)
print "random seed =", random_seed
if infile != None: print "input file =", infile
print "end_time =", end_time.number
print "delta_t =", delta_t.number
print "n_workers =", n_workers
print "use_gpu =", use_gpu
print "manage_encounters =", manage_encounters
print "\ninitializing the gravity module"
sys.stdout.flush()
# Note that there are actually three GPU options to test:
#
# 1. use the GPU code and allow GPU use (default)
# 2. use the GPU code but disable GPU use (-g)
# 3. use the non-GPU code (-G)
if gpu_worker == 1:
try:
gravity = grav(number_of_workers = n_workers,
redirection = "none", mode = "gpu")
except Exception as ex:
gravity = grav(number_of_workers = n_workers, redirection = "none")
else:
gravity = grav(number_of_workers = n_workers, redirection = "none")
gravity.initialize_code()
gravity.parameters.set_defaults()
#-----------------------------------------------------------------
if infile == None:
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id+1
print "setting particle masses and radii"
#stars.mass = (1.0 / number_of_stars) | nbody_system.mass
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
stars.radius = 0.02 | nbody_system.length
print "centering stars"
stars.move_to_center()
print "scaling stars to virial equilibrium"
stars.scale_to_standard(smoothing_length_squared
= gravity.parameters.epsilon_squared)
time = 0.0 | nbody_system.time
sys.stdout.flush()
else:
# Read the input data. Units are dynamical.
print "reading file", infile
id = []
mass = []
pos = []
vel = []
f = open(infile, 'r')
count = 0
for line in f:
if len(line) > 0:
count += 1
cols = line.split()
if count == 1: snap = int(cols[0])
elif count == 2: number_of_stars = int(cols[0])
elif count == 3: time = float(cols[0]) | nbody_system.time
else:
if len(cols) >= 8:
id.append(int(cols[0]))
mass.append(float(cols[1]))
pos.append((float(cols[2]),
float(cols[3]), float(cols[4])))
vel.append((float(cols[5]),
float(cols[6]), float(cols[7])))
f.close()
stars = datamodel.Particles(number_of_stars)
stars.id = id
stars.mass = mass | nbody_system.mass
stars.position = pos | nbody_system.length
stars.velocity = vel | nbody_system.speed
stars.radius = 0. | nbody_system.length
# print "IDs:", stars.id.number
sys.stdout.flush()
#-----------------------------------------------------------------
if softening_length == -1 | nbody_system.length:
eps2 = 0.25*(float(number_of_stars))**(-0.666667) \
| nbody_system.length**2
else:
eps2 = softening_length*softening_length
gravity.parameters.timestep_parameter = accuracy_parameter
gravity.parameters.epsilon_squared = eps2
gravity.parameters.use_gpu = use_gpu
# gravity.parameters.manage_encounters = manage_encounters
print "adding particles"
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
print ''
print "number_of_stars =", number_of_stars
print "evolving to time =", end_time.number, \
"in steps of", delta_t.number
sys.stdout.flush()
E0 = print_log(time, gravity)
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
kep = Kepler(redirection = "none")
kep.initialize_code()
multiples_code = multiples.Multiples(gravity, new_smalln, kep)
while time < end_time:
time += delta_t
multiples_code.evolve_model(time)
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
print_log(time, gravity, E0)
sys.stdout.flush()
print ''
gravity.stop()
def run_ph4(infile = None, number_of_stars = 40,
end_time = 10 | nbody_system.time,
delta_t = 1 | nbody_system.time,
n_workers = 1, use_gpu = 1, gpu_worker = 1, gpu_id = -1,
accuracy_parameter = 0.1,
softening_length = -1 | nbody_system.length,
manage_encounters = 1):
if infile != None: print "input file =", infile
print "end_time =", end_time.number
print "delta_t =", delta_t.number
print "n_workers =", n_workers
print "use_gpu =", use_gpu
print "manage_encounters =", manage_encounters
print "\ninitializing the gravity module"
sys.stdout.flush()
# Note that there are actually three GPU options to test:
#
# 1. use the GPU code and allow GPU use (default)
# 2. use the GPU code but disable GPU use (-g)
# 3. use the non-GPU code (-G)
#print "1"; sys.stdout.flush()
gpu = 0
if gpu_worker == 1:
try:
gravity = grav(number_of_workers = n_workers,
redirection = "none", mode = "gpu")
# debugger='valgrind')
gpu = 1
except Exception as ex:
print '*** GPU worker code not found. Reverting to non-GPU code. ***'
gpu = 0
if gpu == 0:
gravity = grav(number_of_workers = n_workers,
redirection = "none")
# debugger='valgrind')
#print "2"; sys.stdout.flush()
gravity.initialize_code()
#print "3"; sys.stdout.flush()
gravity.parameters.set_defaults()
gravity.parameters.gpu_id = gpu_id
#-----------------------------------------------------------------
#print "4"; sys.stdout.flush()
if infile == None:
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id+1
print "setting particle masses and radii"
stars.mass = (1.0 / number_of_stars) | nbody_system.mass
if 0:
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
stars.radius = 0.0 | nbody_system.length
print "centering stars"
stars.move_to_center()
if 0:
print "scaling stars to virial equilibrium"
stars.scale_to_standard(smoothing_length_squared
= gravity.parameters.epsilon_squared)
time = 0.0 | nbody_system.time
sys.stdout.flush()
else:
# Read the input data. Units are dynamical.
print "reading file", infile
id = []
mass = []
pos = []
vel = []
f = open(infile, 'r')
count = 0
for line in f:
if len(line) > 0:
count += 1
cols = line.split()
if count == 1: snap = int(cols[0])
elif count == 2: number_of_stars = int(cols[0])
elif count == 3: time = float(cols[0]) | nbody_system.time
else:
if len(cols) >= 8:
id.append(int(cols[0]))
mass.append(float(cols[1]))
pos.append((float(cols[2]),
float(cols[3]), float(cols[4])))
vel.append((float(cols[5]),
float(cols[6]), float(cols[7])))
f.close()
stars = datamodel.Particles(number_of_stars)
stars.id = id
stars.mass = mass | nbody_system.mass
stars.position = pos | nbody_system.length
stars.velocity = vel | nbody_system.speed
stars.radius = 0. | nbody_system.length
# print "IDs:", stars.id.number
sys.stdout.flush()
#-----------------------------------------------------------------
#print "5"; sys.stdout.flush()
if softening_length == -1 | nbody_system.length:
eps2 = 0.25*(float(number_of_stars))**(-0.666667) \
| nbody_system.length**2
else:
eps2 = softening_length*softening_length
#print "6"; sys.stdout.flush()
gravity.parameters.timestep_parameter = accuracy_parameter
gravity.parameters.epsilon_squared = eps2
gravity.parameters.use_gpu = use_gpu
gravity.parameters.manage_encounters = manage_encounters
print "adding particles"
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
print ''
print "number_of_stars =", number_of_stars
print "evolving to time =", end_time.number, \
"in steps of", delta_t.number
sys.stdout.flush()
E0,cpu0,wall0 = print_log('', time, gravity)
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
while time < end_time:
time += delta_t
gravity.evolve_model(time)
# Ensure that the stars list is consistent with the internal
# data in the module.
ls = len(stars)
# Update the bookkeeping: synchronize stars with the module data.
try:
gravity.update_particle_set()
gravity.particles.synchronize_to(stars)
except:
pass
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
if stopping_condition.is_set():
star1 = stopping_condition.particles(0)[0]
star2 = stopping_condition.particles(1)[0]
print '\nstopping condition set at time', \
gravity.get_time().number,'for:\n'
print star1
print ''
print star2
print ''
raise Exception("no encounter handling")
if len(stars) != ls:
if 0:
print "stars:"
for s in stars:
print " ", s.id.number, s.mass.number, \
s.x.number, s.y.number, s.z.number
else:
print "number of stars =", len(stars)
sys.stdout.flush()
print_log('', time, gravity, E0, cpu0, wall0)
sys.stdout.flush()
print ''
gravity.stop()
def run_smallN(infile = None, number_of_stars = 10,
end_time = 10 | nbody_system.time,
delta_t = 1 | nbody_system.time,
accuracy_parameter = 0.1):
if infile != None: print "input file =", infile
print "end_time =", end_time.number
print "delta_t =", delta_t.number
print "\ninitializing the gravity module"
sys.stdout.flush()
gravity = grav(redirection = "none")
gravity.initialize_code()
gravity.parameters.set_defaults()
#-----------------------------------------------------------------
if infile == None:
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id+1
print "setting particle masses and radii"
#stars.mass = (1.0 / number_of_stars) | nbody_system.mass
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
stars.radius = 0.0 | nbody_system.length
print "centering stars"
stars.move_to_center()
print "scaling stars to virial equilibrium"
stars.scale_to_standard(smoothing_length_squared = 0 \
| nbody_system.length*nbody_system.length)
time = 0.0 | nbody_system.time
sys.stdout.flush()
else:
# Read the input data. Units are dynamical.
print "reading file", infile
id = []
mass = []
pos = []
vel = []
f = open(infile, 'r')
count = 0
for line in f:
if len(line) > 0:
count += 1
cols = line.split()
if count == 1: snap = int(cols[0])
elif count == 2: number_of_stars = int(cols[0])
elif count == 3: time = float(cols[0]) | nbody_system.time
else:
if len(cols) >= 8:
id.append(int(cols[0]))
mass.append(float(cols[1]))
pos.append((float(cols[2]),
float(cols[3]), float(cols[4])))
vel.append((float(cols[5]),
float(cols[6]), float(cols[7])))
f.close()
stars = datamodel.Particles(number_of_stars)
stars.id = id
stars.mass = mass | nbody_system.mass
stars.position = pos | nbody_system.length
stars.velocity = vel | nbody_system.speed
stars.radius = 0. | nbody_system.length
# print "IDs:", stars.id.number
sys.stdout.flush()
#-----------------------------------------------------------------
gravity.parameters.timestep_parameter = accuracy_parameter
print "adding particles"
# print stars
sys.stdout.flush()
gravity.parameters.begin_time = time
gravity.particles.add_particles(stars)
print "committing particles"
gravity.commit_particles()
print ''
print "number_of_stars =", number_of_stars
print "evolving to time =", end_time.number, \
"in steps of", delta_t.number
sys.stdout.flush()
E0 = print_log(time, gravity)
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
while time < end_time:
time += delta_t
gravity.evolve_model(time)
# Ensure that the stars list is consistent with the internal
# data in the module.
ls = len(stars)
# Update the bookkeeping: synchronize stars with the module data.
try:
gravity.update_particle_set()
gravity.particles.synchronize_to(stars)
except:
pass
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
if len(stars) != ls:
if 0:
print "stars:"
for s in stars:
print " ", s.id.number, s.mass.number, \
s.x.number, s.y.number, s.z.number
else:
print "number of stars =", len(stars)
sys.stdout.flush()
print_log(time, gravity, E0)
over = gravity.is_over()
if over:
gravity.update_particle_tree()
gravity.update_particle_set()
gravity.particles.synchronize_to(stars)
channel.copy()
channel.copy_attribute("index_in_code", "id")
print "binaries:"
x = trees.BinaryTreesOnAParticleSet(stars, "child1", "child2")
roots = list(x.iter_roots())
for r in roots:
for level, particle in r.iter_levels():
print ' '*level, int(particle.id),
if not particle.child1 is None:
m,a,e = get_binary_elements(particle)
print ' (', m, a, e, ')'
else:
print ''
break
sys.stdout.flush()
if not over:
print '\ninteraction is not over'
gravity.stop()
def make_nbody(number_of_stars = 100, time = 0.0,
n_workers = 1, use_gpu = 1, gpu_worker = 1,
salpeter = 0,
delta_t = 1.0 | nbody_system.time,
timestep_parameter = 0.1,
softening_length = 0.0 | nbody_system.length,
random_seed = 1234):
# Make an N-body system, print out some statistics on it, and save
# it in a restart file. The restart file name is of the form
# 't=nnnn.n.xxx', where the default time is 0.0.
if random_seed <= 0:
numpy.random.seed()
random_seed = numpy.random.randint(1, pow(2,31)-1)
numpy.random.seed(random_seed)
print "random seed =", random_seed
init_smalln()
# Note that there are actually three GPU options:
#
# 1. use the GPU code and allow GPU use (default)
# 2. use the GPU code but disable GPU use (-g)
# 3. use the non-GPU code (-G)
if gpu_worker == 1:
try:
gravity = grav(number_of_workers = n_workers,
redirection = "none", mode = "gpu")
except Exception as ex:
gravity = grav(number_of_workers = n_workers,
redirection = "none")
else:
gravity = grav(number_of_workers = n_workers,
redirection = "none")
gravity.initialize_code()
gravity.parameters.set_defaults()
#-----------------------------------------------------------------
# Make a standard N-body system.
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id+1
print "setting particle masses and radii"
if salpeter == 0:
print 'equal masses'
total_mass = 1.0 | nbody_system.mass
scaled_mass = total_mass / number_of_stars
else:
print 'salpeter mass function'
mmin = 0.5 | nbody_system.mass
mmax = 10.0 | nbody_system.mass
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars,
mass_min = mmin,
mass_max = mmax)
stars.mass = scaled_mass
print "centering stars"
stars.move_to_center()
print "scaling stars to virial equilibrium"
stars.scale_to_standard(smoothing_length_squared
= gravity.parameters.epsilon_squared)
# Set dynamical radii (assuming virial equilibrium and standard
# units). Note that this choice should be refined, and updated
# as the system evolves. Probably the choice of radius should be
# made entirely in the multiples module. TODO. In these units,
# M = 1 and <v^2> = 0.5, so the mean 90-degree turnaround impact
# parameter is
#
# b_90 = G (m_1+m_2) / vrel^2
# = 2 <m> / 2<v^2>
# = 2 / N for equal masses
#
# Taking r_i = m_i / 2<v^2> = m_i in virial equilibrium means
# that, approximately, "contact" means a 90-degree deflection (r_1
# + r_2 = b_90). A more conservative choice with r_i less than
# this value will isolate encounters better, but also place more
# load on the large-N dynamical module.
stars.radius = 0.5*stars.mass.number | nbody_system.length
time = 0.0 | nbody_system.time
# print "IDs:", stars.id.number
print "recentering stars"
stars.move_to_center()
sys.stdout.flush()
#-----------------------------------------------------------------
if softening_length < 0.0 | nbody_system.length:
# Use ~interparticle spacing. Assuming standard units here. TODO
softening_length = 0.5*float(number_of_stars)**(-0.3333333) \
| nbody_system.length
print 'softening length =', softening_length
gravity.parameters.timestep_parameter = timestep_parameter
gravity.parameters.epsilon_squared = softening_length*softening_length
gravity.parameters.use_gpu = use_gpu
print ''
print "adding particles"
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
print ''
print "number_of_stars =", number_of_stars
sys.stdout.flush()
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
# -----------------------------------------------------------------
# Create the coupled code and integrate the system to the desired
# time, managing interactions internally.
kep = init_kepler(stars[0], stars[1])
multiples_code = multiples.Multiples(gravity, new_smalln, kep)
multiples_code.neighbor_perturbation_limit = 0.1
multiples_code.neighbor_veto = True
print ''
print 'multiples_code.initial_scale_factor =', \
multiples_code.initial_scale_factor
print 'multiples_code.neighbor_perturbation_limit =', \
multiples_code.neighbor_perturbation_limit
print 'multiples_code.neighbor_veto =', \
multiples_code.neighbor_veto
print 'multiples_code.final_scale_factor =', \
multiples_code.final_scale_factor
print 'multiples_code.initial_scatter_factor =', \
multiples_code.initial_scatter_factor
print 'multiples_code.final_scatter_factor =', \
multiples_code.final_scatter_factor
print 'multiples_code.retain_binary_apocenter =', \
multiples_code.retain_binary_apocenter
print 'multiples_code.wide_perturbation_limit =', \
multiples_code.wide_perturbation_limit
# Take a dummy step, just in case...
multiples_code.evolve_model(time)
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
pre = "%%% "
E0,cpu0 = print_log(pre, time, multiples_code)
sys.stdout.flush()
# file = 't='+'{:07.2f}'.format(time.number) # fails in Python 2.6
file = 't=%07.2f'%time.number
write_state_to_file(time, stars, gravity, multiples_code,
file, delta_t, E0, cpu0)
tree_copy = multiples_code.root_to_tree.copy()
del multiples_code
sys.stdout.flush()
gravity.stop()
kep.stop()
stop_smalln()
print ''
def run_ph4(infile = None, outfile = None,
number_of_stars = 100, number_of_binaries = 0,
end_time = 10 | nbody_system.time,
delta_t = 1 | nbody_system.time,
n_workers = 1, use_gpu = 1, gpu_worker = 1,
salpeter = 0,
accuracy_parameter = 0.1,
softening_length = 0.0 | nbody_system.length,
manage_encounters = 1, random_seed = 1234):
if random_seed <= 0:
numpy.random.seed()
random_seed = numpy.random.randint(1, pow(2,31)-1)
numpy.random.seed(random_seed)
print "random seed =", random_seed
if infile != None: print "input file =", infile
print "end_time =", end_time.number
print "delta_t =", delta_t.number
print "n_workers =", n_workers
print "use_gpu =", use_gpu
print "manage_encounters =", manage_encounters
print "\ninitializing the gravity module"
sys.stdout.flush()
init_smalln()
# Note that there are actually three GPU options:
#
# 1. use the GPU code and allow GPU use (default)
# 2. use the GPU code but disable GPU use (-g)
# 3. use the non-GPU code (-G)
if gpu_worker == 1:
try:
gravity = grav(number_of_workers = n_workers,
redirection = "none", mode = "gpu")
except Exception as ex:
gravity = grav(number_of_workers = n_workers,
redirection = "none")
else:
gravity = grav(number_of_workers = n_workers,
redirection = "none")
gravity.initialize_code()
gravity.parameters.set_defaults()
#-----------------------------------------------------------------
if infile == None:
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id+1
print "setting particle masses and radii"
if salpeter == 0:
print 'equal masses'
total_mass = 1.0 | nbody_system.mass
scaled_mass = total_mass / number_of_stars
else:
print 'salpeter mass function'
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
print "centering stars"
stars.move_to_center()
print "scaling stars to virial equilibrium"
stars.scale_to_standard(smoothing_length_squared
= gravity.parameters.epsilon_squared)
else:
# Read the input data. Units are dynamical (sorry).
# Format: id mass pos[3] vel[3]
print "reading file", infile
id = []
mass = []
pos = []
vel = []
f = open(infile, 'r')
count = 0
for line in f:
if len(line) > 0:
count += 1
cols = line.split()
if count == 1: snap = int(cols[0])
elif count == 2: number_of_stars = int(cols[0])
elif count == 3: time = float(cols[0]) | nbody_system.time
else:
if len(cols) >= 8:
id.append(int(cols[0]))
mass.append(float(cols[1]))
pos.append((float(cols[2]),
float(cols[3]), float(cols[4])))
vel.append((float(cols[5]),
float(cols[6]), float(cols[7])))
f.close()
stars = datamodel.Particles(number_of_stars)
stars.id = id
stars.mass = mass | nbody_system.mass
stars.position = pos | nbody_system.length
stars.velocity = vel | nbody_system.speed
#stars.radius = 0. | nbody_system.length
total_mass = stars.mass.sum()
ke = pa.kinetic_energy(stars)
kT = ke/(1.5*number_of_stars)
if number_of_binaries > 0:
# Turn selected stars into binary components.
# Only tested for equal-mass case.
kep = Kepler(redirection = "none")
kep.initialize_code()
added_mass = 0.0 | nbody_system.mass
# Work with energies rather than semimajor axes.
Emin = 10*kT
Emax = 20*kT
ecc = 0.1
id_count = number_of_stars
nbin = 0
for i in range(0, number_of_stars,
number_of_stars/number_of_binaries):
# Star i is CM, becomes component, add other star at end.
nbin += 1
mass = stars[i].mass
new_mass = numpy.random.uniform()*mass # uniform q?
mbin = mass + new_mass
fac = new_mass/mbin
E = Emin + numpy.random.uniform()*(Emax-Emin)
a = 0.5*nbody_system.G*mass*new_mass/E
kep.initialize_from_elements(mbin, a, ecc)
dr = quantities.AdaptingVectorQuantity()
dr.extend(kep.get_separation_vector())
dv = quantities.AdaptingVectorQuantity()
dv.extend(kep.get_velocity_vector())
newstar = datamodel.Particles(1)
newstar.mass = new_mass
newstar.position = stars[i].position + (1-fac)*dr
newstar.velocity = stars[i].velocity + (1-fac)*dv
# stars[i].mass = mass
stars[i].position = stars[i].position - fac*dr
stars[i].velocity = stars[i].velocity - fac*dv
id_count += 1
newstar.id = id_count
stars.add_particles(newstar)
added_mass += new_mass
if nbin >= number_of_binaries: break
kep.stop()
print 'created', nbin, 'binaries'
sys.stdout.flush()
stars.mass = stars.mass * total_mass/(total_mass+added_mass)
number_of_stars += nbin
# Set dynamical radii (assuming virial equilibrium and standard
# units). Note that this choice should be refined, and updated
# as the system evolves. Probably the choice of radius should be
# made entirely in the multiples module. TODO. In these units,
# M = 1 and <v^2> = 0.5, so the mean 90-degree turnaround impact
# parameter is
#
# b_90 = G (m_1+m_2) / vrel^2
# = 2 <m> / 2<v^2>
# = 2 / N for equal masses
#
# Taking r_i = m_i / 2<v^2> = m_i in virial equilibrium means
# that, approximately, "contact" means a 90-degree deflection (r_1
# + r_2 = b_90). A more conservative choice with r_i less than
# this value will isolates encounters better, but also place more
# load on the large-N dynamical module.
stars.radius = stars.mass.number | nbody_system.length
time = 0.0 | nbody_system.time
# print "IDs:", stars.id.number
print "recentering stars"
stars.move_to_center()
sys.stdout.flush()
#-----------------------------------------------------------------
if softening_length < 0.0 | nbody_system.length:
# Use ~interparticle spacing. Assuming standard units here. TODO
eps2 = 0.25*(float(number_of_stars))**(-0.666667) \
| nbody_system.length**2
else:
eps2 = softening_length*softening_length
print 'softening length =', eps2.sqrt()
gravity.parameters.timestep_parameter = accuracy_parameter
gravity.parameters.epsilon_squared = eps2
gravity.parameters.use_gpu = use_gpu
# gravity.parameters.manage_encounters = manage_encounters
print ''
print "adding particles"
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
print ''
print "number_of_stars =", number_of_stars
print "evolving to time =", end_time.number, \
"in steps of", delta_t.number
sys.stdout.flush()
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
# Debugging: prevent the multiples code from being called.
if 0:
stopping_condition.disable()
print 'stopping condition disabled'
sys.stdout.flush()
# -----------------------------------------------------------------
# Create the coupled code and integrate the system to the desired
# time, managing interactions internally.
kep = init_kepler(stars[0], stars[1])
multiples_code = multiples.Multiples(gravity, new_smalln, kep)
multiples_code.neighbor_perturbation_limit = 0.1
#multiples_code.neighbor_distance_factor = 1.0
#multiples_code.neighbor_veto = False
#multiples_code.neighbor_distance_factor = 2.0
multiples_code.neighbor_veto = True
print ''
print 'multiples_code.initial_scale_factor =', \
multiples_code.initial_scale_factor
print 'multiples_code.neighbor_perturbation_limit =', \
multiples_code.neighbor_perturbation_limit
print 'multiples_code.neighbor_veto =', \
multiples_code.neighbor_veto
print 'multiples_code.final_scale_factor =', \
multiples_code.final_scale_factor
print 'multiples_code.initial_scatter_factor =', \
multiples_code.initial_scatter_factor
print 'multiples_code.final_scatter_factor =', \
multiples_code.final_scatter_factor
print 'multiples_code.retain_binary_apocenter =', \
multiples_code.retain_binary_apocenter
print 'multiples_code.wide_perturbation_limit =', \
multiples_code.wide_perturbation_limit
pre = "%%% "
E0,cpu0 = print_log(pre, time, multiples_code)
while time < end_time:
time += delta_t
multiples_code.evolve_model(time)
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
print_log(pre, time, multiples_code, E0, cpu0)
sys.stdout.flush()
#-----------------------------------------------------------------
if not outfile == None:
# Write data to a file.
f = open(outfile, 'w')
#--------------------------------------------------
# Need to save top-level stellar data and parameters.
# Need to save multiple data and parameters.
f.write('%.15g\n'%(time.number))
for s in multiples_code.stars: write_star(s, f)
#--------------------------------------------------
f.close()
print 'wrote file', outfile
print ''
gravity.stop()
def test6(self):
print "Test all particle attributes using Hop - each different function creates its own instance of Hop"
numpy.random.seed(123)
nbody_plummer = new_plummer_sphere(100)
nbody_plummer.mass = new_salpeter_mass_distribution_nbody(100)
# Each different function creates its own instance of Hop
result = nbody_plummer.new_particle_from_cluster_core(reuse_hop=True)
result = nbody_plummer.bound_subset(G=nbody_system.G, reuse_hop=True)
result = nbody_plummer.mass_segregation_Gini_coefficient(
reuse_hop=True)
result = nbody_plummer.LagrangianRadii(reuse_hop=True)
result = nbody_plummer.densitycentre_coreradius_coredens(
reuse_hop=True)
converter = nbody_system.nbody_to_si(1.0 | units.MSun,
1.0 | units.parsec)
si_plummer = ParticlesWithUnitsConverted(
nbody_plummer, converter.as_converter_from_si_to_nbody())
functions_using_hop = [
si_plummer.new_particle_from_cluster_core, si_plummer.bound_subset,
si_plummer.mass_segregation_Gini_coefficient,
si_plummer.LagrangianRadii,
si_plummer.densitycentre_coreradius_coredens
]
# Each fails since the Hop instance it tries to reuse has a different unit_converter
for function_using_hop in functions_using_hop:
self.assertRaises(
ConvertArgumentsException,
function_using_hop,
unit_converter=converter,
expected_message=
"error while converting parameter 'mass', error: Cannot express kg in mass, the units do not have the same bases"
)
# Close all Hop instances:
nbody_results = []
nbody_results.append(
nbody_plummer.new_particle_from_cluster_core(reuse_hop=False))
nbody_results.append(
nbody_plummer.bound_subset(G=nbody_system.G, reuse_hop=False))
nbody_results.append(
nbody_plummer.mass_segregation_Gini_coefficient(reuse_hop=False))
nbody_results.append(nbody_plummer.LagrangianRadii(reuse_hop=False))
nbody_results.append(
nbody_plummer.densitycentre_coreradius_coredens(reuse_hop=False))
# Now it works, because the Hop instances were closed, and new ones will be instantiated
si_results = []
for function_using_hop in functions_using_hop:
si_results.append(function_using_hop(unit_converter=converter))
convert = converter.as_converter_from_si_to_nbody()
self.assertAlmostRelativeEqual(
si_results[0].position,
ParticlesWithUnitsConverted(nbody_results[0].as_set(),
convert)[0].position)
self.assertAlmostRelativeEqual(
si_results[1].position,
ParticlesWithUnitsConverted(nbody_results[1], convert).position)
self.assertAlmostRelativeEqual(si_results[2],
nbody_results[2],
places=10)
self.assertAlmostRelativeEqual(si_results[3][0],
convert.from_target_to_source(
nbody_results[3][0]),
places=10)
for in_si, in_nbody in zip(si_results[4], nbody_results[4]):
self.assertAlmostRelativeEqual(
in_si, convert.from_target_to_source(in_nbody), places=10)
def run_ph4(infile=None,
number_of_stars=40,
end_time=10 | nbody_system.time,
delta_t=1 | nbody_system.time,
n_workers=1,
use_gpu=1,
gpu_worker=1,
gpu_id=-1,
accuracy_parameter=0.1,
softening_length=-1 | nbody_system.length,
manage_encounters=1):
if infile != None: print "input file =", infile
print "end_time =", end_time.number
print "delta_t =", delta_t.number
print "n_workers =", n_workers
print "use_gpu =", use_gpu
print "manage_encounters =", manage_encounters
print "\ninitializing the gravity module"
sys.stdout.flush()
# Note that there are actually three GPU options to test:
#
# 1. use the GPU code and allow GPU use (default)
# 2. use the GPU code but disable GPU use (-g)
# 3. use the non-GPU code (-G)
#print "1"; sys.stdout.flush()
gpu = 0
if gpu_worker == 1:
try:
gravity = grav(number_of_workers=n_workers,
redirection="none",
mode="gpu")
# debugger='valgrind')
gpu = 1
except Exception as ex:
print '*** GPU worker code not found. Reverting to non-GPU code. ***'
gpu = 0
if gpu == 0:
gravity = grav(number_of_workers=n_workers, redirection="none")
# debugger='valgrind')
#print "2"; sys.stdout.flush()
gravity.initialize_code()
#print "3"; sys.stdout.flush()
gravity.parameters.set_defaults()
gravity.parameters.gpu_id = gpu_id
#-----------------------------------------------------------------
#print "4"; sys.stdout.flush()
if infile == None:
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id + 1
print "setting particle masses and radii"
stars.mass = (1.0 / number_of_stars) | nbody_system.mass
if 0:
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
stars.radius = 0.0 | nbody_system.length
print "centering stars"
stars.move_to_center()
if 0:
print "scaling stars to virial equilibrium"
stars.scale_to_standard(
smoothing_length_squared=gravity.parameters.epsilon_squared)
time = 0.0 | nbody_system.time
sys.stdout.flush()
else:
# Read the input data. Units are dynamical.
print "reading file", infile
id = []
mass = []
pos = []
vel = []
f = open(infile, 'r')
count = 0
for line in f:
if len(line) > 0:
count += 1
cols = line.split()
if count == 1: snap = int(cols[0])
elif count == 2: number_of_stars = int(cols[0])
elif count == 3: time = float(cols[0]) | nbody_system.time
else:
if len(cols) >= 8:
id.append(int(cols[0]))
mass.append(float(cols[1]))
pos.append(
(float(cols[2]), float(cols[3]), float(cols[4])))
vel.append(
(float(cols[5]), float(cols[6]), float(cols[7])))
f.close()
stars = datamodel.Particles(number_of_stars)
stars.id = id
stars.mass = mass | nbody_system.mass
stars.position = pos | nbody_system.length
stars.velocity = vel | nbody_system.speed
stars.radius = 0. | nbody_system.length
# print "IDs:", stars.id.number
sys.stdout.flush()
#-----------------------------------------------------------------
#print "5"; sys.stdout.flush()
if softening_length == -1 | nbody_system.length:
eps2 = 0.25*(float(number_of_stars))**(-0.666667) \
| nbody_system.length**2
else:
eps2 = softening_length * softening_length
#print "6"; sys.stdout.flush()
gravity.parameters.timestep_parameter = accuracy_parameter
gravity.parameters.epsilon_squared = eps2
gravity.parameters.use_gpu = use_gpu
gravity.parameters.manage_encounters = manage_encounters
print "adding particles"
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
print ''
print "number_of_stars =", number_of_stars
print "evolving to time =", end_time.number, \
"in steps of", delta_t.number
sys.stdout.flush()
E0, cpu0, wall0 = print_log('', time, gravity)
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
while time < end_time:
time += delta_t
gravity.evolve_model(time)
# Ensure that the stars list is consistent with the internal
# data in the module.
ls = len(stars)
# Update the bookkeeping: synchronize stars with the module data.
try:
gravity.update_particle_set()
gravity.particles.synchronize_to(stars)
except:
pass
# Copy values from the module to the set in memory.
channel.copy()
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
channel.copy_attribute("index_in_code", "id")
if stopping_condition.is_set():
star1 = stopping_condition.particles(0)[0]
star2 = stopping_condition.particles(1)[0]
print '\nstopping condition set at time', \
gravity.get_time().number,'for:\n'
print star1
print ''
print star2
print ''
raise Exception("no encounter handling")
if len(stars) != ls:
if 0:
print "stars:"
for s in stars:
print " ", s.id.number, s.mass.number, \
s.x.number, s.y.number, s.z.number
else:
print "number of stars =", len(stars)
sys.stdout.flush()
print_log('', time, gravity, E0, cpu0, wall0)
sys.stdout.flush()
print ''
gravity.stop()
def run_hacs(infile = None,
number_of_stars = 128,
nmax = 2048,
end_time = 0.1 | nbody_system.time,
delta_t = 0.125 | nbody_system.time,
dt_max = 0.0625 | nbody_system.time,
n_ngb = 16,
eta_irr = 0.6,
eta_reg = 0.1,
softening_length = 0.0 | nbody_system.length):
if infile != None: print "input file =", infile
print "end_time =", end_time.number
print "nstars= ", number_of_stars,
print "nmax= ", nmax,
print "delta_t= ", delta_t.number
print "dt_max= ", dt_max.number
print "n_ngb= ", n_ngb,
print "eta_irr= ", eta_irr
print "eta_reg= ", eta_reg
print "eps2= ", softening_length.number**2
print "\ninitializing the gravity module"
sys.stdout.flush()
# gravity = grav(number_of_workers = 1, redirection = "none", mode='cpu')
gravity = grav(number_of_workers = 1, redirection = "none", mode='cpu')
gravity.initialize_code()
#-----------------------------------------------------------------
if infile == None:
print "making a Plummer model"
stars = new_plummer_model(number_of_stars)
id = numpy.arange(number_of_stars)
stars.id = id+1
print "setting particle masses and radii"
#stars.mass = (1.0 / number_of_stars) | nbody_system.mass
scaled_mass = new_salpeter_mass_distribution_nbody(number_of_stars)
stars.mass = scaled_mass
stars.radius = 0.0 | nbody_system.length
print "centering stars"
stars.move_to_center()
print "scaling stars to virial equilibrium"
stars.scale_to_standard(smoothing_length_squared
= gravity.parameters.eps2)
time = 0.0 | nbody_system.time
sys.stdout.flush()
else:
# Read the input data. Units are dynamical.
print "reading file", infile
id = []
mass = []
pos = []
vel = []
f = open(infile, 'r')
count = 0
for line in f:
if len(line) > 0:
count += 1
cols = line.split()
if count == 1: snap = int(cols[0])
elif count == 2: number_of_stars = int(cols[0])
elif count == 3: time = float(cols[0]) | nbody_system.time
else:
if len(cols) >= 8:
id.append(int(cols[0]))
mass.append(float(cols[1]))
pos.append((float(cols[2]),
float(cols[3]), float(cols[4])))
vel.append((float(cols[5]),
float(cols[6]), float(cols[7])))
f.close()
stars = datamodel.Particles(number_of_stars)
stars.id = id
print len(mass), len(pos), len(vel), len(id)
stars.mass = mass | nbody_system.mass
stars.position = pos | nbody_system.length
stars.velocity = vel | nbody_system.speed
stars.radius = 0. | nbody_system.length
nmax = 2*len(mass)
# print "IDs:", stars.id.number
sys.stdout.flush()
#-----------------------------------------------------------------
gravity.parameters.nmax = nmax;
gravity.parameters.dtmax = dt_max;
# gravity.parameters.n_ngb = n_ngb;
gravity.parameters.eta_irr = eta_irr;
gravity.parameters.eta_reg = eta_reg;
gravity.parameters.eps2 = softening_length**2
gravity.commit_parameters();
print "adding particles"
# print stars
sys.stdout.flush()
gravity.particles.add_particles(stars)
gravity.commit_particles()
print ''
print "number_of_stars =", number_of_stars
print "evolving to time =", end_time.number, \
"in steps of", delta_t.number
sys.stdout.flush()
E0 = print_log(time, gravity)
# Channel to copy values from the code to the set in memory.
channel = gravity.particles.new_channel_to(stars)
stopping_condition = gravity.stopping_conditions.collision_detection
stopping_condition.enable()
# stopping_condition.disable()
while time < end_time:
if (gravity.get_time() >= time):
time += delta_t
gravity.evolve_model(time)
# Ensure that the stars list is consistent with the internal
# data in the module.
ls = len(stars)
# Update the bookkeeping: synchronize stars with the module data.
# this breaks the code ...
channel.copy()
# Copy values from the module to the set in memory.
channel.copy_attribute("index_in_code", "id")
# Copy the index (ID) as used in the module to the id field in
# memory. The index is not copied by default, as different
# codes may have different indices for the same particle and
# we don't want to overwrite silently.
if stopping_condition.is_set():
star1 = stopping_condition.particles(0)[0]
star2 = stopping_condition.particles(1)[0]
gravity.synchronize_model()
print '\nstopping condition set at time', \
gravity.get_time().number,'for:\n'
print star1
print ''
print star2
print ''
gravity.particles.remove_particle(star1)
gravity.particles.remove_particle(star2)
gravity.recommit_particles();
print 'ls=', len(stars)
gravity.update_particle_set()
gravity.particles.synchronize_to(stars)
print 'ls=', len(stars)
if len(stars) != ls:
if 0:
print "stars:"
for s in stars:
print " ", s.id.number, s.mass.number, s.x.number, s.y.number, s.z.number
else:
print "number of stars =", len(stars)
sys.stdout.flush()
print_log(gravity.get_time(), gravity, E0)
sys.stdout.flush()
print ''
print_log(gravity.get_time(), gravity, E0)
sys.stdout.flush()
gravity.stop()