def testConstantODE2(self):
iv = np.array([1.0])
h: np.float = 0.1
y = odesolvers.ImplicitEulerSolver(constantode, iv, self.t0, self.tn,
h, constantodeJ)
self.assertEqual(y[0], iv)
self.assertGreater(y[1], y[0])
def testStableODE2(self):
iv = np.array([1.0])
h: np.float = 0.01
y = odesolvers.ImplicitEulerSolver(stableode, iv, self.t0, self.tn, h,
stableodeJ)
self.assertEqual(y[0], iv)
self.assertLess(y[1], y[0])
def testMultivariableODE(self):
iv = np.array([1.0, 2.0])
h: np.float = 0.01
y = odesolvers.ImplicitEulerSolver(multivariableode, iv, self.t0,
self.tn, h, multivariableodeJ)
self.assertEqual(y[0, 0], iv[0])
self.assertEqual(y[0, 1], iv[1])
self.assertLess(y[1, 1], y[0, 1])
def testStiffODE2(self):
iv = np.array([1.0, 2.0])
h: np.float = 0.05
N: np.uint = np.uint(np.ceil((self.tn - self.t0) / h))
# final step
y = odesolvers.ImplicitEulerSolver(stiffode, iv, self.t0, self.tn, h,
stiffodeJ)
self.assertEqual(y[0, 0], iv[0])
self.assertEqual(y[0, 1], iv[1])
self.assertLess(np.absolute(y[N, 1] - y[0, 1]), 3)
def testNewtonItConvergenceFail(self):
iv = np.array([1.0, 2.0])
h: np.float = 0.01
with self.assertRaises(ArithmeticError):
odesolvers.ImplicitEulerSolver(multivariableode,
iv,
self.t0,
self.tn,
h,
multivariableodeJ,
NEWTITER=0)