def test_dynamic_forward(self):
nfe = 5
m = make_dynamic_model(nfe=nfe, scheme="FORWARD")
time = m.time
t0 = time.first()
m.flow_in.fix()
m.height[t0].fix()
solve_strongly_connected_components(m)
for con in m.component_data_objects(pyo.Constraint):
# Sanity check that this is an equality constraint...
self.assertEqual(pyo.value(con.upper), pyo.value(con.lower))
# Assert that the constraint is satisfied within tolerance
self.assertAlmostEqual(pyo.value(con.body),
pyo.value(con.upper),
delta=1e-7)
for t in time:
if t == t0:
self.assertTrue(m.height[t].fixed)
else:
self.assertFalse(m.height[t].fixed)
self.assertFalse(m.flow_out[t].fixed)
self.assertFalse(m.dhdt[t].fixed)
self.assertTrue(m.flow_in[t].fixed)
def test_dynamic_backward_no_solver(self):
nfe = 5
m = make_dynamic_model(nfe=nfe, scheme="BACKWARD")
time = m.time
t0 = time.first()
m.flow_in.fix()
m.height[t0].fix()
with self.assertRaisesRegex(RuntimeError,
"An external solver is required*"):
solve_strongly_connected_components(m)
for t in time:
if t == t0:
self.assertTrue(m.height[t].fixed)
else:
self.assertFalse(m.height[t].fixed)
self.assertFalse(m.flow_out[t].fixed)
self.assertFalse(m.dhdt[t].fixed)
self.assertTrue(m.flow_in[t].fixed)
def test_with_calc_var_kwds(self):
m = pyo.ConcreteModel()
m.v0 = pyo.Var()
m.v1 = pyo.Var()
m.v2 = pyo.Var(initialize=79703634.05074187)
m.v2.fix()
m.p0 = pyo.Param(initialize=3e5)
m.p1 = pyo.Param(initialize=1.296e12)
m.con0 = pyo.Constraint(expr=m.v0 == m.p0)
m.con1 = pyo.Constraint(expr=0.0 == m.p1 * m.v1 / m.v0 + m.v2)
calc_var_kwds = {"eps": 1e-7}
# This solve fails to converge without raising the tolerance.
# The secant method used to converge a linear variable-constraint
# pair (such as con0, v0 and con1, v1) leaves us with a residual of
# 1.48e-8 due to roundoff error.
results = solve_strongly_connected_components(
m, calc_var_kwds=calc_var_kwds)
self.assertEqual(len(results), 2)
self.assertAlmostEqual(m.v0.value, m.p0.value)
self.assertAlmostEqual(m.v1.value, -18.4499152895)