Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/scipy/integrate/tests/test_integrate.py

@@ -0,0 +1,830 @@
+# Authors: Nils Wagner, Ed Schofield, Pauli Virtanen, John Travers
+"""
+Tests for numerical integration.
+"""
+import numpy as np
+from numpy import (arange, zeros, array, dot, sqrt, cos, sin, eye, pi, exp,
+                   allclose)
+
+from numpy.testing import (
+    assert_, assert_array_almost_equal,
+    assert_allclose, assert_array_equal, assert_equal, assert_warns)
+from pytest import raises as assert_raises
+from scipy.integrate import odeint, ode, complex_ode
+
+#------------------------------------------------------------------------------
+# Test ODE integrators
+#------------------------------------------------------------------------------
+
+
+class TestOdeint(object):
+    # Check integrate.odeint
+
+    def _do_problem(self, problem):
+        t = arange(0.0, problem.stop_t, 0.05)
+
+        # Basic case
+        z, infodict = odeint(problem.f, problem.z0, t, full_output=True)
+        assert_(problem.verify(z, t))
+
+        # Use tfirst=True
+        z, infodict = odeint(lambda t, y: problem.f(y, t), problem.z0, t,
+                             full_output=True, tfirst=True)
+        assert_(problem.verify(z, t))
+
+        if hasattr(problem, 'jac'):
+            # Use Dfun
+            z, infodict = odeint(problem.f, problem.z0, t, Dfun=problem.jac,
+                                 full_output=True)
+            assert_(problem.verify(z, t))
+
+            # Use Dfun and tfirst=True
+            z, infodict = odeint(lambda t, y: problem.f(y, t), problem.z0, t,
+                                 Dfun=lambda t, y: problem.jac(y, t),
+                                 full_output=True, tfirst=True)
+            assert_(problem.verify(z, t))
+
+    def test_odeint(self):
+        for problem_cls in PROBLEMS:
+            problem = problem_cls()
+            if problem.cmplx:
+                continue
+            self._do_problem(problem)
+
+
+class TestODEClass(object):
+
+    ode_class = None   # Set in subclass.
+
+    def _do_problem(self, problem, integrator, method='adams'):
+
+        # ode has callback arguments in different order than odeint
+        f = lambda t, z: problem.f(z, t)
+        jac = None
+        if hasattr(problem, 'jac'):
+            jac = lambda t, z: problem.jac(z, t)
+
+        integrator_params = {}
+        if problem.lband is not None or problem.uband is not None:
+            integrator_params['uband'] = problem.uband
+            integrator_params['lband'] = problem.lband
+
+        ig = self.ode_class(f, jac)
+        ig.set_integrator(integrator,
+                          atol=problem.atol/10,
+                          rtol=problem.rtol/10,
+                          method=method,
+                          **integrator_params)
+
+        ig.set_initial_value(problem.z0, t=0.0)
+        z = ig.integrate(problem.stop_t)
+
+        assert_array_equal(z, ig.y)
+        assert_(ig.successful(), (problem, method))
+        assert_(ig.get_return_code() > 0, (problem, method))
+        assert_(problem.verify(array([z]), problem.stop_t), (problem, method))
+
+
+class TestOde(TestODEClass):
+
+    ode_class = ode
+
+    def test_vode(self):
+        # Check the vode solver
+        for problem_cls in PROBLEMS:
+            problem = problem_cls()
+            if problem.cmplx:
+                continue
+            if not problem.stiff:
+                self._do_problem(problem, 'vode', 'adams')
+            self._do_problem(problem, 'vode', 'bdf')
+
+    def test_zvode(self):
+        # Check the zvode solver
+        for problem_cls in PROBLEMS:
+            problem = problem_cls()
+            if not problem.stiff:
+                self._do_problem(problem, 'zvode', 'adams')
+            self._do_problem(problem, 'zvode', 'bdf')
+
+    def test_lsoda(self):
+        # Check the lsoda solver
+        for problem_cls in PROBLEMS:
+            problem = problem_cls()
+            if problem.cmplx:
+                continue
+            self._do_problem(problem, 'lsoda')
+
+    def test_dopri5(self):
+        # Check the dopri5 solver
+        for problem_cls in PROBLEMS:
+            problem = problem_cls()
+            if problem.cmplx:
+                continue
+            if problem.stiff:
+                continue
+            if hasattr(problem, 'jac'):
+                continue
+            self._do_problem(problem, 'dopri5')
+
+    def test_dop853(self):
+        # Check the dop853 solver
+        for problem_cls in PROBLEMS:
+            problem = problem_cls()
+            if problem.cmplx:
+                continue
+            if problem.stiff:
+                continue
+            if hasattr(problem, 'jac'):
+                continue
+            self._do_problem(problem, 'dop853')
+
+    def test_concurrent_fail(self):
+        for sol in ('vode', 'zvode', 'lsoda'):
+            f = lambda t, y: 1.0
+
+            r = ode(f).set_integrator(sol)
+            r.set_initial_value(0, 0)
+
+            r2 = ode(f).set_integrator(sol)
+            r2.set_initial_value(0, 0)
+
+            r.integrate(r.t + 0.1)
+            r2.integrate(r2.t + 0.1)
+
+            assert_raises(RuntimeError, r.integrate, r.t + 0.1)
+
+    def test_concurrent_ok(self):
+        f = lambda t, y: 1.0
+
+        for k in range(3):
+            for sol in ('vode', 'zvode', 'lsoda', 'dopri5', 'dop853'):
+                r = ode(f).set_integrator(sol)
+                r.set_initial_value(0, 0)
+
+                r2 = ode(f).set_integrator(sol)
+                r2.set_initial_value(0, 0)
+
+                r.integrate(r.t + 0.1)
+                r2.integrate(r2.t + 0.1)
+                r2.integrate(r2.t + 0.1)
+
+                assert_allclose(r.y, 0.1)
+                assert_allclose(r2.y, 0.2)
+
+            for sol in ('dopri5', 'dop853'):
+                r = ode(f).set_integrator(sol)
+                r.set_initial_value(0, 0)
+
+                r2 = ode(f).set_integrator(sol)
+                r2.set_initial_value(0, 0)
+
+                r.integrate(r.t + 0.1)
+                r.integrate(r.t + 0.1)
+                r2.integrate(r2.t + 0.1)
+                r.integrate(r.t + 0.1)
+                r2.integrate(r2.t + 0.1)
+
+                assert_allclose(r.y, 0.3)
+                assert_allclose(r2.y, 0.2)
+
+
+class TestComplexOde(TestODEClass):
+
+    ode_class = complex_ode
+
+    def test_vode(self):
+        # Check the vode solver
+        for problem_cls in PROBLEMS:
+            problem = problem_cls()
+            if not problem.stiff:
+                self._do_problem(problem, 'vode', 'adams')
+            else:
+                self._do_problem(problem, 'vode', 'bdf')
+
+    def test_lsoda(self):
+        # Check the lsoda solver
+        for problem_cls in PROBLEMS:
+            problem = problem_cls()
+            self._do_problem(problem, 'lsoda')
+
+    def test_dopri5(self):
+        # Check the dopri5 solver
+        for problem_cls in PROBLEMS:
+            problem = problem_cls()
+            if problem.stiff:
+                continue
+            if hasattr(problem, 'jac'):
+                continue
+            self._do_problem(problem, 'dopri5')
+
+    def test_dop853(self):
+        # Check the dop853 solver
+        for problem_cls in PROBLEMS:
+            problem = problem_cls()
+            if problem.stiff:
+                continue
+            if hasattr(problem, 'jac'):
+                continue
+            self._do_problem(problem, 'dop853')
+
+
+class TestSolout(object):
+    # Check integrate.ode correctly handles solout for dopri5 and dop853
+    def _run_solout_test(self, integrator):
+        # Check correct usage of solout
+        ts = []
+        ys = []
+        t0 = 0.0
+        tend = 10.0
+        y0 = [1.0, 2.0]
+
+        def solout(t, y):
+            ts.append(t)
+            ys.append(y.copy())
+
+        def rhs(t, y):
+            return [y[0] + y[1], -y[1]**2]
+
+        ig = ode(rhs).set_integrator(integrator)
+        ig.set_solout(solout)
+        ig.set_initial_value(y0, t0)
+        ret = ig.integrate(tend)
+        assert_array_equal(ys[0], y0)
+        assert_array_equal(ys[-1], ret)
+        assert_equal(ts[0], t0)
+        assert_equal(ts[-1], tend)
+
+    def test_solout(self):
+        for integrator in ('dopri5', 'dop853'):
+            self._run_solout_test(integrator)
+
+    def _run_solout_after_initial_test(self, integrator):
+        # Check if solout works even if it is set after the initial value.
+        ts = []
+        ys = []
+        t0 = 0.0
+        tend = 10.0
+        y0 = [1.0, 2.0]
+
+        def solout(t, y):
+            ts.append(t)
+            ys.append(y.copy())
+
+        def rhs(t, y):
+            return [y[0] + y[1], -y[1]**2]
+
+        ig = ode(rhs).set_integrator(integrator)
+        ig.set_initial_value(y0, t0)
+        ig.set_solout(solout)
+        ret = ig.integrate(tend)
+        assert_array_equal(ys[0], y0)
+        assert_array_equal(ys[-1], ret)
+        assert_equal(ts[0], t0)
+        assert_equal(ts[-1], tend)
+
+    def test_solout_after_initial(self):
+        for integrator in ('dopri5', 'dop853'):
+            self._run_solout_after_initial_test(integrator)
+
+    def _run_solout_break_test(self, integrator):
+        # Check correct usage of stopping via solout
+        ts = []
+        ys = []
+        t0 = 0.0
+        tend = 10.0
+        y0 = [1.0, 2.0]
+
+        def solout(t, y):
+            ts.append(t)
+            ys.append(y.copy())
+            if t > tend/2.0:
+                return -1
+
+        def rhs(t, y):
+            return [y[0] + y[1], -y[1]**2]
+
+        ig = ode(rhs).set_integrator(integrator)
+        ig.set_solout(solout)
+        ig.set_initial_value(y0, t0)
+        ret = ig.integrate(tend)
+        assert_array_equal(ys[0], y0)
+        assert_array_equal(ys[-1], ret)
+        assert_equal(ts[0], t0)
+        assert_(ts[-1] > tend/2.0)
+        assert_(ts[-1] < tend)
+
+    def test_solout_break(self):
+        for integrator in ('dopri5', 'dop853'):
+            self._run_solout_break_test(integrator)
+
+
+class TestComplexSolout(object):
+    # Check integrate.ode correctly handles solout for dopri5 and dop853
+    def _run_solout_test(self, integrator):
+        # Check correct usage of solout
+        ts = []
+        ys = []
+        t0 = 0.0
+        tend = 20.0
+        y0 = [0.0]
+
+        def solout(t, y):
+            ts.append(t)
+            ys.append(y.copy())
+
+        def rhs(t, y):
+            return [1.0/(t - 10.0 - 1j)]
+
+        ig = complex_ode(rhs).set_integrator(integrator)
+        ig.set_solout(solout)
+        ig.set_initial_value(y0, t0)
+        ret = ig.integrate(tend)
+        assert_array_equal(ys[0], y0)
+        assert_array_equal(ys[-1], ret)
+        assert_equal(ts[0], t0)
+        assert_equal(ts[-1], tend)
+
+    def test_solout(self):
+        for integrator in ('dopri5', 'dop853'):
+            self._run_solout_test(integrator)
+
+    def _run_solout_break_test(self, integrator):
+        # Check correct usage of stopping via solout
+        ts = []
+        ys = []
+        t0 = 0.0
+        tend = 20.0
+        y0 = [0.0]
+
+        def solout(t, y):
+            ts.append(t)
+            ys.append(y.copy())
+            if t > tend/2.0:
+                return -1
+
+        def rhs(t, y):
+            return [1.0/(t - 10.0 - 1j)]
+
+        ig = complex_ode(rhs).set_integrator(integrator)
+        ig.set_solout(solout)
+        ig.set_initial_value(y0, t0)
+        ret = ig.integrate(tend)
+        assert_array_equal(ys[0], y0)
+        assert_array_equal(ys[-1], ret)
+        assert_equal(ts[0], t0)
+        assert_(ts[-1] > tend/2.0)
+        assert_(ts[-1] < tend)
+
+    def test_solout_break(self):
+        for integrator in ('dopri5', 'dop853'):
+            self._run_solout_break_test(integrator)
+
+
+#------------------------------------------------------------------------------
+# Test problems
+#------------------------------------------------------------------------------
+
+
+class ODE:
+    """
+    ODE problem
+    """
+    stiff = False
+    cmplx = False
+    stop_t = 1
+    z0 = []
+
+    lband = None
+    uband = None
+
+    atol = 1e-6
+    rtol = 1e-5
+
+
+class SimpleOscillator(ODE):
+    r"""
+    Free vibration of a simple oscillator::
+        m \ddot{u} + k u = 0, u(0) = u_0 \dot{u}(0) \dot{u}_0
+    Solution::
+        u(t) = u_0*cos(sqrt(k/m)*t)+\dot{u}_0*sin(sqrt(k/m)*t)/sqrt(k/m)
+    """
+    stop_t = 1 + 0.09
+    z0 = array([1.0, 0.1], float)
+
+    k = 4.0
+    m = 1.0
+
+    def f(self, z, t):
+        tmp = zeros((2, 2), float)
+        tmp[0, 1] = 1.0
+        tmp[1, 0] = -self.k / self.m
+        return dot(tmp, z)
+
+    def verify(self, zs, t):
+        omega = sqrt(self.k / self.m)
+        u = self.z0[0]*cos(omega*t) + self.z0[1]*sin(omega*t)/omega
+        return allclose(u, zs[:, 0], atol=self.atol, rtol=self.rtol)
+
+
+class ComplexExp(ODE):
+    r"""The equation :lm:`\dot u = i u`"""
+    stop_t = 1.23*pi
+    z0 = exp([1j, 2j, 3j, 4j, 5j])
+    cmplx = True
+
+    def f(self, z, t):
+        return 1j*z
+
+    def jac(self, z, t):
+        return 1j*eye(5)
+
+    def verify(self, zs, t):
+        u = self.z0 * exp(1j*t)
+        return allclose(u, zs, atol=self.atol, rtol=self.rtol)
+
+
+class Pi(ODE):
+    r"""Integrate 1/(t + 1j) from t=-10 to t=10"""
+    stop_t = 20
+    z0 = [0]
+    cmplx = True
+
+    def f(self, z, t):
+        return array([1./(t - 10 + 1j)])
+
+    def verify(self, zs, t):
+        u = -2j * np.arctan(10)
+        return allclose(u, zs[-1, :], atol=self.atol, rtol=self.rtol)
+
+
+class CoupledDecay(ODE):
+    r"""
+    3 coupled decays suited for banded treatment
+    (banded mode makes it necessary when N>>3)
+    """
+
+    stiff = True
+    stop_t = 0.5
+    z0 = [5.0, 7.0, 13.0]
+    lband = 1
+    uband = 0
+
+    lmbd = [0.17, 0.23, 0.29]  # fictitious decay constants
+
+    def f(self, z, t):
+        lmbd = self.lmbd
+        return np.array([-lmbd[0]*z[0],
+                         -lmbd[1]*z[1] + lmbd[0]*z[0],
+                         -lmbd[2]*z[2] + lmbd[1]*z[1]])
+
+    def jac(self, z, t):
+        # The full Jacobian is
+        #
+        #    [-lmbd[0]      0         0   ]
+        #    [ lmbd[0]  -lmbd[1]      0   ]
+        #    [    0      lmbd[1]  -lmbd[2]]
+        #
+        # The lower and upper bandwidths are lband=1 and uband=0, resp.
+        # The representation of this array in packed format is
+        #
+        #    [-lmbd[0]  -lmbd[1]  -lmbd[2]]
+        #    [ lmbd[0]   lmbd[1]      0   ]
+
+        lmbd = self.lmbd
+        j = np.zeros((self.lband + self.uband + 1, 3), order='F')
+
+        def set_j(ri, ci, val):
+            j[self.uband + ri - ci, ci] = val
+        set_j(0, 0, -lmbd[0])
+        set_j(1, 0, lmbd[0])
+        set_j(1, 1, -lmbd[1])
+        set_j(2, 1, lmbd[1])
+        set_j(2, 2, -lmbd[2])
+        return j
+
+    def verify(self, zs, t):
+        # Formulae derived by hand
+        lmbd = np.array(self.lmbd)
+        d10 = lmbd[1] - lmbd[0]
+        d21 = lmbd[2] - lmbd[1]
+        d20 = lmbd[2] - lmbd[0]
+        e0 = np.exp(-lmbd[0] * t)
+        e1 = np.exp(-lmbd[1] * t)
+        e2 = np.exp(-lmbd[2] * t)
+        u = np.vstack((
+            self.z0[0] * e0,
+            self.z0[1] * e1 + self.z0[0] * lmbd[0] / d10 * (e0 - e1),
+            self.z0[2] * e2 + self.z0[1] * lmbd[1] / d21 * (e1 - e2) +
+            lmbd[1] * lmbd[0] * self.z0[0] / d10 *
+            (1 / d20 * (e0 - e2) - 1 / d21 * (e1 - e2)))).transpose()
+        return allclose(u, zs, atol=self.atol, rtol=self.rtol)
+
+
+PROBLEMS = [SimpleOscillator, ComplexExp, Pi, CoupledDecay]
+
+#------------------------------------------------------------------------------
+
+
+def f(t, x):
+    dxdt = [x[1], -x[0]]
+    return dxdt
+
+
+def jac(t, x):
+    j = array([[0.0, 1.0],
+               [-1.0, 0.0]])
+    return j
+
+
+def f1(t, x, omega):
+    dxdt = [omega*x[1], -omega*x[0]]
+    return dxdt
+
+
+def jac1(t, x, omega):
+    j = array([[0.0, omega],
+               [-omega, 0.0]])
+    return j
+
+
+def f2(t, x, omega1, omega2):
+    dxdt = [omega1*x[1], -omega2*x[0]]
+    return dxdt
+
+
+def jac2(t, x, omega1, omega2):
+    j = array([[0.0, omega1],
+               [-omega2, 0.0]])
+    return j
+
+
+def fv(t, x, omega):
+    dxdt = [omega[0]*x[1], -omega[1]*x[0]]
+    return dxdt
+
+
+def jacv(t, x, omega):
+    j = array([[0.0, omega[0]],
+               [-omega[1], 0.0]])
+    return j
+
+
+class ODECheckParameterUse(object):
+    """Call an ode-class solver with several cases of parameter use."""
+
+    # solver_name must be set before tests can be run with this class.
+
+    # Set these in subclasses.
+    solver_name = ''
+    solver_uses_jac = False
+
+    def _get_solver(self, f, jac):
+        solver = ode(f, jac)
+        if self.solver_uses_jac:
+            solver.set_integrator(self.solver_name, atol=1e-9, rtol=1e-7,
+                                  with_jacobian=self.solver_uses_jac)
+        else:
+            # XXX Shouldn't set_integrator *always* accept the keyword arg
+            # 'with_jacobian', and perhaps raise an exception if it is set
+            # to True if the solver can't actually use it?
+            solver.set_integrator(self.solver_name, atol=1e-9, rtol=1e-7)
+        return solver
+
+    def _check_solver(self, solver):
+        ic = [1.0, 0.0]
+        solver.set_initial_value(ic, 0.0)
+        solver.integrate(pi)
+        assert_array_almost_equal(solver.y, [-1.0, 0.0])
+
+    def test_no_params(self):
+        solver = self._get_solver(f, jac)
+        self._check_solver(solver)
+
+    def test_one_scalar_param(self):
+        solver = self._get_solver(f1, jac1)
+        omega = 1.0
+        solver.set_f_params(omega)
+        if self.solver_uses_jac:
+            solver.set_jac_params(omega)
+        self._check_solver(solver)
+
+    def test_two_scalar_params(self):
+        solver = self._get_solver(f2, jac2)
+        omega1 = 1.0
+        omega2 = 1.0
+        solver.set_f_params(omega1, omega2)
+        if self.solver_uses_jac:
+            solver.set_jac_params(omega1, omega2)
+        self._check_solver(solver)
+
+    def test_vector_param(self):
+        solver = self._get_solver(fv, jacv)
+        omega = [1.0, 1.0]
+        solver.set_f_params(omega)
+        if self.solver_uses_jac:
+            solver.set_jac_params(omega)
+        self._check_solver(solver)
+
+    def test_warns_on_failure(self):
+        # Set nsteps small to ensure failure
+        solver = self._get_solver(f, jac)
+        solver.set_integrator(self.solver_name, nsteps=1)
+        ic = [1.0, 0.0]
+        solver.set_initial_value(ic, 0.0)
+        assert_warns(UserWarning, solver.integrate, pi)
+
+
+class TestDOPRI5CheckParameterUse(ODECheckParameterUse):
+    solver_name = 'dopri5'
+    solver_uses_jac = False
+
+
+class TestDOP853CheckParameterUse(ODECheckParameterUse):
+    solver_name = 'dop853'
+    solver_uses_jac = False
+
+
+class TestVODECheckParameterUse(ODECheckParameterUse):
+    solver_name = 'vode'
+    solver_uses_jac = True
+
+
+class TestZVODECheckParameterUse(ODECheckParameterUse):
+    solver_name = 'zvode'
+    solver_uses_jac = True
+
+
+class TestLSODACheckParameterUse(ODECheckParameterUse):
+    solver_name = 'lsoda'
+    solver_uses_jac = True
+
+
+def test_odeint_trivial_time():
+    # Test that odeint succeeds when given a single time point
+    # and full_output=True.  This is a regression test for gh-4282.
+    y0 = 1
+    t = [0]
+    y, info = odeint(lambda y, t: -y, y0, t, full_output=True)
+    assert_array_equal(y, np.array([[y0]]))
+
+
+def test_odeint_banded_jacobian():
+    # Test the use of the `Dfun`, `ml` and `mu` options of odeint.
+
+    def func(y, t, c):
+        return c.dot(y)
+
+    def jac(y, t, c):
+        return c
+
+    def jac_transpose(y, t, c):
+        return c.T.copy(order='C')
+
+    def bjac_rows(y, t, c):
+        jac = np.row_stack((np.r_[0, np.diag(c, 1)],
+                            np.diag(c),
+                            np.r_[np.diag(c, -1), 0],
+                            np.r_[np.diag(c, -2), 0, 0]))
+        return jac
+
+    def bjac_cols(y, t, c):
+        return bjac_rows(y, t, c).T.copy(order='C')
+
+    c = array([[-205, 0.01, 0.00, 0.0],
+               [0.1, -2.50, 0.02, 0.0],
+               [1e-3, 0.01, -2.0, 0.01],
+               [0.00, 0.00, 0.1, -1.0]])
+
+    y0 = np.ones(4)
+    t = np.array([0, 5, 10, 100])
+
+    # Use the full Jacobian.
+    sol1, info1 = odeint(func, y0, t, args=(c,), full_output=True,
+                         atol=1e-13, rtol=1e-11, mxstep=10000,
+                         Dfun=jac)
+
+    # Use the transposed full Jacobian, with col_deriv=True.
+    sol2, info2 = odeint(func, y0, t, args=(c,), full_output=True,
+                         atol=1e-13, rtol=1e-11, mxstep=10000,
+                         Dfun=jac_transpose, col_deriv=True)
+
+    # Use the banded Jacobian.
+    sol3, info3 = odeint(func, y0, t, args=(c,), full_output=True,
+                         atol=1e-13, rtol=1e-11, mxstep=10000,
+                         Dfun=bjac_rows, ml=2, mu=1)
+
+    # Use the transposed banded Jacobian, with col_deriv=True.
+    sol4, info4 = odeint(func, y0, t, args=(c,), full_output=True,
+                         atol=1e-13, rtol=1e-11, mxstep=10000,
+                         Dfun=bjac_cols, ml=2, mu=1, col_deriv=True)
+
+    assert_allclose(sol1, sol2, err_msg="sol1 != sol2")
+    assert_allclose(sol1, sol3, atol=1e-12, err_msg="sol1 != sol3")
+    assert_allclose(sol3, sol4, err_msg="sol3 != sol4")
+
+    # Verify that the number of jacobian evaluations was the same for the
+    # calls of odeint with a full jacobian and with a banded jacobian. This is
+    # a regression test--there was a bug in the handling of banded jacobians
+    # that resulted in an incorrect jacobian matrix being passed to the LSODA
+    # code.  That would cause errors or excessive jacobian evaluations.
+    assert_array_equal(info1['nje'], info2['nje'])
+    assert_array_equal(info3['nje'], info4['nje'])
+
+    # Test the use of tfirst
+    sol1ty, info1ty = odeint(lambda t, y, c: func(y, t, c), y0, t, args=(c,),
+                             full_output=True, atol=1e-13, rtol=1e-11,
+                             mxstep=10000,
+                             Dfun=lambda t, y, c: jac(y, t, c), tfirst=True)
+    # The code should execute the exact same sequence of floating point
+    # calculations, so these should be exactly equal. We'll be safe and use
+    # a small tolerance.
+    assert_allclose(sol1, sol1ty, rtol=1e-12, err_msg="sol1 != sol1ty")
+
+
+def test_odeint_errors():
+    def sys1d(x, t):
+        return -100*x
+
+    def bad1(x, t):
+        return 1.0/0
+
+    def bad2(x, t):
+        return "foo"
+
+    def bad_jac1(x, t):
+        return 1.0/0
+
+    def bad_jac2(x, t):
+        return [["foo"]]
+
+    def sys2d(x, t):
+        return [-100*x[0], -0.1*x[1]]
+
+    def sys2d_bad_jac(x, t):
+        return [[1.0/0, 0], [0, -0.1]]
+
+    assert_raises(ZeroDivisionError, odeint, bad1, 1.0, [0, 1])
+    assert_raises(ValueError, odeint, bad2, 1.0, [0, 1])
+
+    assert_raises(ZeroDivisionError, odeint, sys1d, 1.0, [0, 1], Dfun=bad_jac1)
+    assert_raises(ValueError, odeint, sys1d, 1.0, [0, 1], Dfun=bad_jac2)
+
+    assert_raises(ZeroDivisionError, odeint, sys2d, [1.0, 1.0], [0, 1],
+                  Dfun=sys2d_bad_jac)
+
+
+def test_odeint_bad_shapes():
+    # Tests of some errors that can occur with odeint.
+
+    def badrhs(x, t):
+        return [1, -1]
+
+    def sys1(x, t):
+        return -100*x
+
+    def badjac(x, t):
+        return [[0, 0, 0]]
+
+    # y0 must be at most 1-d.
+    bad_y0 = [[0, 0], [0, 0]]
+    assert_raises(ValueError, odeint, sys1, bad_y0, [0, 1])
+
+    # t must be at most 1-d.
+    bad_t = [[0, 1], [2, 3]]
+    assert_raises(ValueError, odeint, sys1, [10.0], bad_t)
+
+    # y0 is 10, but badrhs(x, t) returns [1, -1].
+    assert_raises(RuntimeError, odeint, badrhs, 10, [0, 1])
+
+    # shape of array returned by badjac(x, t) is not correct.
+    assert_raises(RuntimeError, odeint, sys1, [10, 10], [0, 1], Dfun=badjac)
+
+
+def test_repeated_t_values():
+    """Regression test for gh-8217."""
+
+    def func(x, t):
+        return -0.25*x
+
+    t = np.zeros(10)
+    sol = odeint(func, [1.], t)
+    assert_array_equal(sol, np.ones((len(t), 1)))
+
+    tau = 4*np.log(2)
+    t = [0]*9 + [tau, 2*tau, 2*tau, 3*tau]
+    sol = odeint(func, [1, 2], t, rtol=1e-12, atol=1e-12)
+    expected_sol = np.array([[1.0, 2.0]]*9 +
+                            [[0.5, 1.0],
+                             [0.25, 0.5],
+                             [0.25, 0.5],
+                             [0.125, 0.25]])
+    assert_allclose(sol, expected_sol)
+
+    # Edge case: empty t sequence.
+    sol = odeint(func, [1.], [])
+    assert_array_equal(sol, np.array([], dtype=np.float64).reshape((0, 1)))
+
+    # t values are not monotonic.
+    assert_raises(ValueError, odeint, func, [1.], [0, 1, 0.5, 0])
+    assert_raises(ValueError, odeint, func, [1, 2, 3], [0, -1, -2, 3])