def test_exact(self, scheme): self.sys = VerticalRollingDisk() self.scheme = scheme ohm_phi = 2. ohm_theta = 1. phi_0 = 0 self.u0 = self.sys.initial(np.array([0,0,phi_0,0.,0,0,ohm_phi,ohm_theta,0,0])) R = self.sys.radius m = self.sys.mass # consistent initial velocities vx = self.u0[4] = R*ohm_theta*np.cos(phi_0) vy = self.u0[5] = R*ohm_theta*np.sin(phi_0) # lagrange multipliers: used only used as a guess in RK methods self.u0[8], self.u0[9] = -m*ohm_phi*R*ohm_theta*np.sin(phi_0), m*ohm_phi*R*ohm_theta*np.cos(phi_0) self.scheme.h = self.h self.s = Solver(self.scheme, self.sys) self.s.initialize(self.u0,) self.s.run(1.) ## self.s.plot(components=[6,7]) self.check_solution()
def test_dynamics(self):
u, us = self.prepare()
d = self.co.multi_dynamics(u)
ds = self.co.multi_dynamics(us)
for k in d:
npt.assert_array_almost_equal(ds[k] - d[k].reshape(-1, 1), 0)
def test_initial(self):
z0s = np.linspace(-.9, .9, 10) * np.sqrt(2)
u0 = self.co.initial_cos(z0s[5])
u00 = ContactSystem.initial(self.co, u0)
self.assertFalse(u0 is u00)
npt.assert_almost_equal(u0, u00)
@pytest.fixture(params=[ContactOscillator(), VerticalRollingDisk()])
def sys(request):
return request.param
def test_constraint(sys, nb_stages=4):
u = np.random.random_sample([sys.size, nb_stages])
constraints = sys.constraint(u)
for U, C in zip(u.T, constraints.T):
npt.assert_array_almost_equal(
np.dot(sys.codistribution(U), sys.velocity(U)), C)
def test_reaction_force(sys, nb_stages=4):
u = np.random.random_sample([sys.size, nb_stages])
force = sys.reaction_force(u)
