def test3(self):
self.assertRaises(
AmuseException,
StickySpheres,
mass_loss=-0.1,
expected_message="Mass-loss fraction must be in the range [0, 1)")
self.assertRaises(
AmuseException,
StickySpheres,
mass_loss=1.0,
expected_message="Mass-loss fraction must be in the range [0, 1)")
particles = Particles(6)
particles.mass = range(1, 7) | units.kg
particles.position = [[i, 1.0, 2.0] for i in range(1, 7)] | units.m
particles.velocity = [[1.0, 0.0, 1.0], [0.0, -1.0, -1.0]
] | units.m / units.s
for fraction in [0.01, 0.1, 0.5]:
sticky_spheres = StickySpheres(mass_loss=fraction)
for i in range(0, 6, 2):
colliders = particles[i:i + 2]
merged = sticky_spheres.handle_collision(
colliders[0], colliders[1])
self.assertTrue(isinstance(merged, Particles))
self.assertAlmostEqual(merged.mass, (2 * i + 3.0) *
(1 - fraction) | units.kg)
self.assertAlmostEqual(merged.position,
[((i + 1)**2 + (i + 2)**2) /
(2 * i + 3.0), 1.0, 2.0] | units.m)
self.assertAlmostEqual(
merged.velocity,
([i + 1, -(i + 2), -1.0] | units.m / units.s) /
(2 * i + 3.0))
def test2(self):
colliders = Particles(2)
colliders.mass = [5, 5] | units.kg
colliders.position = [[0.0, 0.0, 0.0], [1.0, 1.0, 1.0]] | units.m
colliders.velocity = [[0.0, 0.0, 0.0], [2.0, 2.0, 2.0]] | units.m / units.s
merged = StickySpheres(mass_loss=0.2).handle_collision(colliders[0], colliders[1])
self.assertTrue(isinstance(merged, Particles))
self.assertEqual(merged.mass, 8 | units.kg)
self.assertAlmostEqual(merged.position, [0.5, 0.5, 0.5] | units.m)
self.assertAlmostEqual(merged.velocity, [1.0, 1.0, 1.0] | units.m / units.s)
copy = colliders.copy()
copy.move_to_center()
self.assertAlmostEqual(colliders.kinetic_energy(), merged.as_set().kinetic_energy() / 0.8 + copy.kinetic_energy())
def test2(self):
colliders = Particles(2)
colliders.mass = [5, 5] | units.kg
colliders.position = [[0.0, 0.0, 0.0], [1.0, 1.0, 1.0]] | units.m
colliders.velocity = [[0.0, 0.0, 0.0], [2.0, 2.0, 2.0]] | units.m / units.s
merged = StickySpheres(mass_loss=0.2).handle_collision(colliders[0], colliders[1])
self.assertTrue(isinstance(merged, Particles))
self.assertEqual(merged.mass, 8 | units.kg)
self.assertAlmostEqual(merged.position, [0.5, 0.5, 0.5] | units.m)
self.assertAlmostEqual(merged.velocity, [1.0, 1.0, 1.0] | units.m / units.s)
copy = colliders.copy()
copy.move_to_center()
self.assertAlmostEqual(colliders.kinetic_energy(), merged.as_set().kinetic_energy() / 0.8 + copy.kinetic_energy())
def test1(self):
colliders = Particles(2)
colliders.mass = [5, 2] | units.kg
colliders.position = [[0.0, 0.0, 0.0], [0.7, 1.4, -0.35]] | units.m
colliders.velocity = [[0.4, -0.6, 0.0], [0.0, 0.0, -3.0]] | units.m / units.s
self.assertAlmostEqual(colliders.center_of_mass_velocity().length(), 1.0 | units.m / units.s)
merged = StickySpheres().handle_collision(colliders[0], colliders[1])
self.assertTrue(isinstance(merged, Particles))
self.assertEqual(merged.mass, 7 | units.kg)
self.assertAlmostEqual(merged.position, [0.2, 0.4, -0.1] | units.m)
self.assertAlmostEqual(merged.velocity, ([2.0, -3.0, -6.0] | units.m / units.s) / 7.0)
self.assertAlmostEqual(merged.velocity.length(), 1.0 | units.m / units.s)
copy = colliders.copy()
copy.move_to_center()
self.assertAlmostEqual(colliders.kinetic_energy(), merged.as_set().kinetic_energy() + copy.kinetic_energy())
def test1(self):
colliders = Particles(2)
colliders.mass = [5, 2] | units.kg
colliders.position = [[0.0, 0.0, 0.0], [0.7, 1.4, -0.35]] | units.m
colliders.velocity = [[0.4, -0.6, 0.0], [0.0, 0.0, -3.0]] | units.m / units.s
self.assertAlmostEqual(colliders.center_of_mass_velocity().length(), 1.0 | units.m / units.s)
merged = StickySpheres().handle_collision(colliders[0], colliders[1])
self.assertTrue(isinstance(merged, Particles))
self.assertEqual(merged.mass, 7 | units.kg)
self.assertAlmostEqual(merged.position, [0.2, 0.4, -0.1] | units.m)
self.assertAlmostEqual(merged.velocity, ([2.0, -3.0, -6.0] | units.m / units.s) / 7.0)
self.assertAlmostEqual(merged.velocity.length(), 1.0 | units.m / units.s)
copy = colliders.copy()
copy.move_to_center()
self.assertAlmostEqual(colliders.kinetic_energy(), merged.as_set().kinetic_energy() + copy.kinetic_energy())
def test9(self):
print "Test CollisionHandler with gravity code and StickySpheres collision code"
gravity = GravityCodeForTesting()
self.assertEqual(len(gravity.particles), 6)
gravity.particles.mass = [
1,
1,
2,
2,
3,
3,
] | units.MSun
gravity.particles.radius = range(101, 107) | units.RSun
collision_code = StickySpheres(mass_loss=0.1)
handler = CollisionHandler(collision_code, gravity_code=gravity)
merged = handler.handle_collisions(gravity.particles[::2],
gravity.particles[1::2])
self.assertTrue(isinstance(merged, Particles))
self.assertEqual(len(merged), 3)
self.assertEqual(merged.mass, 0.9 * ([2, 4, 6] | units.MSun))
self.assertEqual(len(gravity.particles), 3)
self.assertEqual(gravity.particles.mass,
0.9 * ([2, 4, 6] | units.MSun))
self.assertEqual(gravity.particles.radius,
[102, 104, 106] | units.RSun)
self.assertAlmostEqual(
gravity.particles.position,
[[0.5, 1.0, 1.5], [2.5, 5.0, 7.5], [4.5, 9.0, 13.5]] | units.AU)
self.assertAlmostEqual(
gravity.particles.velocity,
[[0.5, 0.5, 0.5], [2.5, 6.5, 17.5], [4.5, 20.5, 94.5]]
| units.km / units.s)
def test3(self):
self.assertRaises(AmuseException, StickySpheres, mass_loss=-0.1, expected_message=
"Mass-loss fraction must be in the range [0, 1)")
self.assertRaises(AmuseException, StickySpheres, mass_loss=1.0, expected_message=
"Mass-loss fraction must be in the range [0, 1)")
particles = Particles(6)
particles.mass = range(1, 7) | units.kg
particles.position = [[i, 1.0, 2.0] for i in range(1, 7)] | units.m
particles.velocity = [[1.0, 0.0, 1.0], [0.0, -1.0, -1.0]] | units.m / units.s
for fraction in [0.01, 0.1, 0.5]:
sticky_spheres = StickySpheres(mass_loss=fraction)
for i in range(0, 6, 2):
colliders = particles[i:i+2]
merged = sticky_spheres.handle_collision(colliders[0], colliders[1])
self.assertTrue(isinstance(merged, Particles))
self.assertAlmostEqual(merged.mass,
(2 * i +3.0) * (1 - fraction) | units.kg)
self.assertAlmostEqual(merged.position,
[((i+1)**2 + (i+2)**2)/(2*i+3.0), 1.0, 2.0] | units.m)
self.assertAlmostEqual(merged.velocity,
([i+1, -(i+2), -1.0] | units.m / units.s) / (2*i+3.0))
