def test2(self):
seed(1)
particles=new_plummer_model(10000)
instance = Agama(type="Multipole", particles=particles)
result=instance.get_potential_at_point(
0.|generic_unit_system.length,
0.|generic_unit_system.length,
0.|generic_unit_system.length,
0.|generic_unit_system.length)
self.assertLess(abs(result/(-16./3/3.1416|
generic_unit_system.length**2/generic_unit_system.time**2) - 1), 0.04)
scaleM=1234|units.MSun
scaleR=5.6 |units.parsec
converter=nbody_system.nbody_to_si(scaleM,scaleR)
particles=new_plummer_model(20000, convert_nbody=converter)
instance = Agama(converter, type="Multipole", particles=particles)
x=3.|units.parsec
y=4.|units.parsec
z=5.|units.parsec
r=(x*x+y*y+z*z)**0.5
result=instance.get_gravity_at_point(0|units.parsec, x, y, z)
expected=-constants.G*scaleM/(r*r+(3*3.1416/16*scaleR)**2)**1.5*x
self.assertLess(abs(result[0]/expected-1), 0.03)
self.assertLess(abs(result[2]/result[0]-z/x), 0.03)
instance.stop()
def test1(self):
M=10.
a=2.
x=1.
y=2.
z=3.
r=(x*x+y*y+z*z)**0.5
instance = Agama(type="Dehnen",
mass=M|generic_unit_system.mass, scaleRadius=a|generic_unit_system.length)
result=instance.get_potential_at_point(
0.|generic_unit_system.length,
x |generic_unit_system.length,
y |generic_unit_system.length,
z |generic_unit_system.length)
self.assertAlmostEqual(result.value_in(
generic_unit_system.length**2/generic_unit_system.time**2), -M/(r+a), places=14)
result=instance.get_gravity_at_point(
0.|generic_unit_system.length,
x |generic_unit_system.length,
y |generic_unit_system.length,
z |generic_unit_system.length)
self.assertAlmostEqual(result[0].value_in(
generic_unit_system.length/generic_unit_system.time**2), -M/(r+a)**2 * x/r, places=14)
self.assertAlmostEqual(result[0],result[2]/3, places=14)
scaleM=2.345678|units.MSun
scalea=7.654321|units.parsec
converter=nbody_system.nbody_to_si(scaleM, scalea)
instance = Agama(converter, type="Dehnen", mass=M*scaleM, scaleradius=a*scalea)
result=instance.get_gravity_at_point(
0.|generic_unit_system.length, x*scalea, y*scalea, z*scalea)
scale=M/(r+a)**2 *scaleM/scalea**2*constants.G
self.assertAlmostEqual(result[0], scale * x/r, places=10)
instance.stop()
def test1(self):
M=10.
a=2.
x=1.
y=2.
z=3.
r=(x*x+y*y+z*z)**0.5
instance = Agama(type="Dehnen", mass=M|generic_unit_system.mass, scaleRadius=a|generic_unit_system.length)
result=instance.get_potential_at_point(
0.|generic_unit_system.length,
x |generic_unit_system.length,
y |generic_unit_system.length,
z |generic_unit_system.length)
self.assertAlmostEqual(result.value_in(generic_unit_system.length**2/generic_unit_system.time**2), -M/(r+a), places=14)
result=instance.get_gravity_at_point(
0.|generic_unit_system.length,
x |generic_unit_system.length,
y |generic_unit_system.length,
z |generic_unit_system.length)
self.assertAlmostEqual(result[0].value_in(generic_unit_system.length/generic_unit_system.time**2), -M/(r+a)**2 * x/r, places=14)
self.assertAlmostEqual(result[0],result[2]/3, places=14)
scaleM=2.345678|units.MSun
scalea=7.654321|units.parsec
converter=nbody_system.nbody_to_si(scaleM, scalea)
instance = Agama(converter, type="Dehnen", mass=M*scaleM, scaleradius=a*scalea)
result=instance.get_gravity_at_point(
0.|generic_unit_system.length, x*scalea, y*scalea, z*scalea)
scale=M/(r+a)**2 *scaleM/scalea**2*constants.G
self.assertAlmostEqual(result[0], scale * x/r, places=10)
instance.stop()
cluster.particles.add_particles(particles)
# set up bridge; cluster is evolved under influence of the galaxy
sys = bridge(verbose=False)
sys.add_system(cluster, (galaxy, ), False)
# evolve and make plots
times = units.Myr([0., 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4])
f = pyplot.figure(figsize=(16, 8))
for i, t in enumerate(times):
sys.evolve_model(t, timestep=timestep)
print("Evolved the system to time %f" % t)
x = sys.particles.x.value_in(units.parsec)
y = sys.particles.y.value_in(units.parsec)
subplot = f.add_subplot(2, 4, i + 1)
subplot.plot(x, y, 'r .')
subplot.plot([0.], [0.], 'b +')
subplot.set_xlim(-60, 60)
subplot.set_ylim(-60, 60)
subplot.set_title(t)
if i == 7:
subplot.set_xlabel('parsec')
cluster.stop()
galaxy.stop()
pyplot.show()
# pyplot.savefig('test.eps')
# set up bridge; cluster is evolved under influence of the galaxy
sys = bridge(verbose=False)
sys.add_system(cluster, (galaxy,), False)
# evolve and make plots
times = units.Myr([0.,0.2,0.4,0.6,0.8,1.0,1.2,1.4])
f = pyplot.figure(figsize=(8,16))
for i,t in enumerate(times):
sys.evolve_model(t, timestep=timestep)
print "Evolved the system to time",t
x=sys.particles.x.value_in(units.parsec)
y=sys.particles.y.value_in(units.parsec)
subplot=f.add_subplot(4,2,i+1)
subplot.plot(x,y,'r .')
subplot.plot([0.],[0.],'b +')
subplot.set_xlim(-60,60)
subplot.set_ylim(-60,60)
subplot.set_title(t)
if i==7:
subplot.set_xlabel('parsec')
cluster.stop()
galaxy.stop()
pyplot.show()
# pyplot.savefig('test.eps')
channel_from_stellar_to_gravity.copy()
channel_from_gravity_to_framework.copy()
print("Evolved the system to time %.1f Myr" % t.value_in(units.Myr) +
", total mass=%.1f Msun" %
particles.mass.sum().value_in(units.MSun) +
", Ekin=%.4g Msun*(km/s)^2" %
cluster.kinetic_energy.value_in(units.MSun * units.kms**2) +
", Etot=%.4g Msun*(km/s)^2" %
(cluster.potential_energy +
cluster.kinetic_energy).value_in(units.MSun * units.kms**2))
x = particles.x.value_in(units.parsec)
y = particles.y.value_in(units.parsec)
plt.figure(figsize=(6, 6))
plt.scatter(x,
y,
marker='.',
s=5 * particles.mass.value_in(units.MSun)**0.5,
edgecolors=None,
c='k',
alpha=0.2)
plt.xlim(-5, 5)
plt.ylim(-5, 5)
plt.title("t=%.1f Myr" % t.value_in(units.Myr))
basename = 'example_amuse_raga' if useRaga else 'example_amuse_nbody'
plt.savefig('%s_%i.png' % (basename, i))
plt.close()
cluster.stop()
stellarevol.stop()
