def test_simple_integration_forward(self):
p = om.Problem(model=om.Group())
phase = dm.Phase(ode_class=TestODE,
transcription=dm.RungeKutta(num_segments=200,
method='RK4'))
p.model.add_subsystem('phase0', subsys=phase)
phase.set_time_options(fix_initial=True,
fix_duration=True,
targets=['t'])
phase.add_state('y',
fix_initial=True,
targets=['y'],
rate_source='ydot',
units='m')
phase.add_timeseries_output('ydot',
output_name='state_rate:y',
units='m/s')
p.setup(check=True, force_alloc_complex=True)
p['phase0.t_initial'] = 0.0
p['phase0.t_duration'] = 2.0
p['phase0.states:y'] = 0.5
p.run_model()
expected = _test_ode_solution(p['phase0.ode.y'], p['phase0.ode.t'])
assert_near_equal(p['phase0.ode.y'], expected, tolerance=1.0E-3)
def test_simple_integration_forward_connected_initial(self):
p = Problem(model=Group())
phase = Phase(ode_class=TestODE,
transcription=RungeKutta(num_segments=200, method='RK4'))
p.model.add_subsystem('phase0', subsys=phase)
phase.set_time_options(fix_initial=True, fix_duration=True)
phase.set_state_options('y', fix_initial=False, connected_initial=True)
phase.add_timeseries_output('ydot',
output_name='state_rate:y',
units='m/s')
p.setup(check=True, force_alloc_complex=True)
p['phase0.t_initial'] = 0.0
p['phase0.t_duration'] = 2.0
# The initial guess of states at the segment boundaries
p['phase0.states:y'] = 0.0
# The initial value of the states from which the integration proceeds
p['phase0.initial_states:y'] = 0.5
p.run_model()
expected = _test_ode_solution(p['phase0.ode.y'], p['phase0.ode.t'])
assert_rel_error(self, p['phase0.ode.y'], expected, tolerance=1.0E-3)
def test_simple_integration_backward(self):
p = Problem(model=Group())
phase = Phase(ode_class=TestODE,
transcription=RungeKutta(num_segments=4, method='RK4'))
p.model.add_subsystem('phase0', subsys=phase)
phase.set_time_options(fix_initial=True, fix_duration=True)
phase.set_state_options('y', fix_initial=True)
phase.add_timeseries_output('ydot',
output_name='state_rate:y',
units='m/s')
p.setup(check=True, force_alloc_complex=True)
p['phase0.t_initial'] = 2.0
p['phase0.t_duration'] = -2.0
p['phase0.states:y'] = 5.305471950534675
p.run_model()
expected = np.atleast_2d(
_test_ode_solution(p['phase0.ode.y'], p['phase0.ode.t'])).T
assert_rel_error(self,
p['phase0.timeseries.states:y'],
expected,
tolerance=1.0E-3)
def test_simple_integration_backward_connected_initial(self):
p = om.Problem(model=om.Group())
phase = dm.Phase(ode_class=TestODE, transcription=dm.RungeKutta(num_segments=200, method='RK4'))
p.model.add_subsystem('phase0', subsys=phase)
phase.set_time_options(fix_initial=True, fix_duration=True, targets=['t'])
phase.add_state('y', connected_initial=True, targets=['y'], rate_source='ydot', units='m')
phase.add_timeseries_output('ydot', output_name='state_rate:y')
p.setup(check=True, force_alloc_complex=True)
p['phase0.t_initial'] = 2.0
p['phase0.t_duration'] = -2.0
# The initial guess of state values at the segment boundaries
p['phase0.states:y'] = 0
# The initial value of the states from which the integration proceeds
p['phase0.initial_states:y'] = 5.305471950534675
p.run_model()
expected = np.atleast_2d(_test_ode_solution(p['phase0.ode.y'], p['phase0.timeseries.time']))
assert_near_equal(p['phase0.timeseries.states:y'], expected, tolerance=1.0E-3)
