def test_returns_right_direction_simple_case(self):
expected = self.pos2 / np.sqrt(2.)
force = n_body_physics.calculate_force(self.m1, self.m2, self.pos1,
self.pos2, self.G)
actual = force / np.linalg.norm(force)
npt.assert_allclose(expected, actual)
def test_returns_results_of_proper_length(self):
expected = self.pos1.size
actual = len(
n_body_physics.calculate_force(self.m1, self.m2, self.pos1,
self.pos2, self.G))
self.assertEqual(expected, actual)
def test_returns_right_mag_simple_case(self):
expected = self.G * self.m1 * self.m2 / 2.
force = n_body_physics.calculate_force(self.m1, self.m2, self.pos1,
self.pos2, self.G)
actual = np.linalg.norm(force)
npt.assert_array_less(0., actual)
npt.assert_allclose(expected, actual)
def test_right_result(self):
# Setup the particles for this particular case
self.particles['masses'] = np.array([1., 2., 3.])
self.particles['positions'] = np.array([[0., 0.], [1., -1.], [1., 2.]])
# Calculate the expected force
expected1 = n_body_physics.calculate_force(
self.particles['masses'][0], self.particles['masses'][1],
self.particles['positions'][0], self.particles['positions'][1],
self.parameters['G'])
expected2 = n_body_physics.calculate_force(
self.particles['masses'][0], self.particles['masses'][2],
self.particles['positions'][0], self.particles['positions'][2],
self.parameters['G'])
expected = expected1 + expected2
actual = self.fn(self.i, self.particles, self.parameters)
npt.assert_allclose(expected, actual)
def test_runs(self):
n_body_physics.calculate_force(self.m1, self.m2, self.pos1, self.pos2,
self.G)