def test13(self):
"""
tests generating cartesian coordinates from orbital elements
"""
numpy.random.seed(17014)
N = 5
mass1 = 1.0 | units.MSun
mass2 = numpy.ones(N) * 0.01 | units.MEarth
sem = 2. | units.AU
ecc = 0.15
inc = 11. | units.deg
lon = 30. | units.deg
arg = 0.3 | units.deg
ta = (360. * random.random() - 180.) | units.deg
rel_pos, rel_vel = rel_posvel_arrays_from_orbital_elements(
mass1, mass2, sem, ecc, ta, inc, lon, arg, G=constants.G)
mass_12 = mass1 + mass2
sem_ext, ecc_ext, ta_ext, inc_ext, lon_ext, arg_ext = \
orbital_elements(
rel_pos, rel_vel, mass_12, G=constants.G)
self.assertAlmostEqual(sem, sem_ext)
self.assertAlmostEqual(ecc, ecc_ext)
self.assertAlmostEqual(inc, inc_ext)
self.assertAlmostEqual(lon, lon_ext)
self.assertAlmostEqual(arg, arg_ext)
self.assertAlmostEqual(ta, ta_ext)
def test14(self):
"""
tests generating cartesian coordinates from orbital elements
"""
numpy.random.seed(17018)
N = 5
mass1 = numpy.ones(N) * 1.0 | units.MSun
mass2 = random.random(N) | units.MEarth
sem = numpy.array([2., 1.0, 1.1, 1.2, 4.0]) | units.AU
ecc = numpy.array([0.15, 0.01, 0.5, 0.9, 0.99])
inc = numpy.array([11., 0.1, 20, 90, 180.]) | units.deg
lon = numpy.array([31., 32., 33., 45., 30.]) | units.deg
arg = numpy.array([0.3, 11., 15., 30., 95.]) | units.deg
ta = (360. * random.random(N) - 180.) | units.deg
rel_pos, rel_vel = rel_posvel_arrays_from_orbital_elements(
mass1, mass2, sem, ecc, ta, inc, lon, arg, G=constants.G)
mass_12 = mass1 + mass2
sem_ext, ecc_ext, ta_ext, inc_ext, lon_ext, arg_ext = \
orbital_elements(
rel_pos, rel_vel, mass_12, G=constants.G)
self.assertAlmostEqual(sem.value_in(units.AU),
sem_ext.value_in(units.AU))
self.assertAlmostEqual(ecc, ecc_ext)
self.assertAlmostEqual(inc, inc_ext)
self.assertAlmostEqual(lon, lon_ext)
self.assertAlmostEqual(arg, arg_ext)
self.assertAlmostEqual(ta, ta_ext)
def test15(self):
"""
testing orbital_elements_for_rel_posvel_arrays for N particles
with random orbital elements
"""
numpy.random.seed(666)
N = 100
mass_sun = 1. | units.MSun
mass1 = numpy.ones(N) * mass_sun
mass2 = numpy.zeros(N) | units.MSun
semi_major_axis = (-numpy.log(random.random(N))) | units.AU
eccentricity = random.random(N)
true_anomaly = 360.*random.random(N)-180.
inclination = 180*random.random(N)
longitude_of_the_ascending_node = 360*random.random(N)-180
argument_of_periapsis = 360*random.random(N)-180
comets = datamodel.Particles(N)
suns = datamodel.Particles(N)
for i, arg in enumerate(
zip(mass1, mass2, semi_major_axis, eccentricity, true_anomaly,
inclination, longitude_of_the_ascending_node,
argument_of_periapsis)):
sun_and_comet = new_binary_from_orbital_elements(
*arg, G=constants.G)
comets[i].mass = sun_and_comet[1].mass
comets[i].position = sun_and_comet[1].position
comets[i].velocity = sun_and_comet[1].velocity
suns.mass = mass1
suns.position = 0*comets.position
suns.velocity = 0*comets.velocity
mass1_ext, mass2_ext, semi_major_axis_ext, eccentricity_ext, ta_ext,\
inclination_ext, longitude_of_the_ascending_node_ext,\
argument_of_periapsis_ext = orbital_elements(
suns, comets, G=constants.G)
rad_to_deg = 180./numpy.pi
for i in range(N):
self.assertAlmostEqual(
semi_major_axis[i].value_in(units.AU),
semi_major_axis_ext[i].value_in(units.AU))
self.assertAlmostEqual(eccentricity[i], eccentricity_ext[i])
self.assertAlmostEqual(
inclination[i], rad_to_deg*inclination_ext[i])
self.assertAlmostEqual(
longitude_of_the_ascending_node[i],
rad_to_deg*longitude_of_the_ascending_node_ext[i])
self.assertAlmostEqual(
argument_of_periapsis[i],
rad_to_deg*argument_of_periapsis_ext[i])
self.assertAlmostEqual(true_anomaly[i], rad_to_deg*ta_ext[i])
def test4(self):
numpy.random.seed(3456789)
N = 100
mass1 = random.random(N) | nbody_system.mass
mass2 = random.random(N) | nbody_system.mass
semi_major_axis = (-numpy.log(random.random(N))) | nbody_system.length
eccentricity = random.random(N)
true_anomaly = (360. * random.random(N) - 180.) | units.deg
inclination = (180 * random.random(N)) | units.deg
longitude_of_the_ascending_node = (360 * random.random(N) -
180) | units.deg
argument_of_periapsis = (360 * random.random(N) - 180) | units.deg
for arg in zip(mass1, mass2, semi_major_axis, eccentricity,
true_anomaly, inclination,
longitude_of_the_ascending_node, argument_of_periapsis):
arg_ = orbital_elements(new_binary_from_orbital_elements(*arg))
for i, (copy, org) in enumerate(zip(arg_, arg)):
self.assertAlmostEqual(copy, org)
def test11(self):
"""
testing orbital_elements_for_rel_posvel_arrays for unbound orbits
"""
from amuse.community.kepler.interface import Kepler
numpy.random.seed(66)
N = 10
mass_sun = 1. | units.MSun
mass1 = numpy.ones(N) * mass_sun
mass2 = numpy.zeros(N) | units.MSun
semi_major_axis=-1000.*(random.random(N)) | units.AU
eccentricity = (1.+random.random(N))*10.-9.
inclination = numpy.pi*random.random(N)
longitude_of_the_ascending_node = 2.*numpy.pi*random.random(N)-numpy.pi
argument_of_periapsis = 2.*numpy.pi*random.random(N)-numpy.pi
# kepler.initialize_from_elements initializes orbits with mean_anomaly=0 and true_anomaly=0
true_anomaly = 0.*(360.*random.random(N)-180.)
comets = datamodel.Particles(N)
converter = nbody_system.nbody_to_si(1|units.MSun,1|units.AU)
kepler = Kepler(converter)
kepler.initialize_code()
for i,arg in enumerate(zip(mass1,mass2,semi_major_axis,eccentricity,true_anomaly,inclination,
longitude_of_the_ascending_node,argument_of_periapsis)):
kepler.initialize_from_elements(mass=(mass1[i]+mass2[i]),
semi=semi_major_axis[i],
ecc=eccentricity[i])
ri = kepler.get_separation_vector()
vi = kepler.get_velocity_vector()
om = longitude_of_the_ascending_node[i]
w = argument_of_periapsis[i]
incl = inclination[i]
a1 = ([numpy.cos(om), -numpy.sin(om), 0.0], [numpy.sin(om), numpy.cos(om), 0.0], [0.0, 0.0, 1.0])
a2 = ([1.0, 0.0, 0.0], [0.0, numpy.cos(incl), -numpy.sin(incl)], [0.0, numpy.sin(incl), numpy.cos(incl)])
a3 = ([numpy.cos(w), -numpy.sin(w), 0.0], [numpy.sin(w), numpy.cos(w), 0.0], [0.0, 0.0, 1.0])
A = numpy.dot(numpy.dot(a1,a2),a3)
r_vec = numpy.dot(A,numpy.reshape(ri,3,1))
v_vec = numpy.dot(A,numpy.reshape(vi,3,1))
r = (0.0, 0.0, 0.0) | units.AU
v = (0.0, 0.0, 0.0) | (units.AU / units.day)
r[0] = r_vec[0]
r[1] = r_vec[1]
r[2] = r_vec[2]
v[0] = v_vec[0]
v[1] = v_vec[1]
v[2] = v_vec[2]
comets[i].mass = mass2[i]
comets[i].position = r_vec
comets[i].velocity = v_vec
kepler.stop()
semi_major_axis_ext, eccentricity_ext, ta_ext, inclination_ext, \
longitude_of_the_ascending_node_ext, argument_of_periapsis_ext = \
orbital_elements(comets.position,
comets.velocity,
comets.mass + mass_sun,
G=constants.G)
self.assertAlmostEqual(semi_major_axis,semi_major_axis_ext.in_(units.AU))
self.assertAlmostEqual(eccentricity,eccentricity_ext)
self.assertAlmostEqual(inclination,inclination_ext)
self.assertAlmostEqual(longitude_of_the_ascending_node,longitude_of_the_ascending_node_ext)
self.assertAlmostEqual(argument_of_periapsis,argument_of_periapsis_ext)
self.assertAlmostEqual(true_anomaly,ta_ext)