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Time Integration
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Tempus_UnitTest_ERK_ForwardEuler.cpp
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1// @HEADER
2// ****************************************************************************
3// Tempus: Copyright (2017) Sandia Corporation
4//
5// Distributed under BSD 3-clause license (See accompanying file Copyright.txt)
6// ****************************************************************************
7// @HEADER
8
10
11#include "../TestModels/DahlquistTestModel.hpp"
12
13
14namespace Tempus_Unit_Test {
15
16using Teuchos::RCP;
17using Teuchos::rcp;
18using Teuchos::rcp_const_cast;
19using Teuchos::rcp_dynamic_cast;
20
21
22// ************************************************************
23// ************************************************************
24TEUCHOS_UNIT_TEST(ERK_ForwardEuler, Default_Construction)
25{
26 auto stepper = rcp(new Tempus::StepperERK_ForwardEuler<double>());
28
29 // Test stepper properties.
30 TEUCHOS_ASSERT(stepper->getOrder() == 1);
31 const auto rk_fe = stepper->getTableau();
32
33 TEUCHOS_ASSERT( rk_fe->isTVD() );
34 TEUCHOS_ASSERT( rk_fe->getTVDCoeff() == 1 );
35}
36
37
38// ************************************************************
39// ************************************************************
40TEUCHOS_UNIT_TEST(ERK_ForwardEuler, StepperFactory_Construction)
41{
42 auto model = rcp(new Tempus_Test::SinCosModel<double>());
43 testFactoryConstruction("RK Forward Euler", model);
44}
45
46
47// ************************************************************
48// ************************************************************
49TEUCHOS_UNIT_TEST(ERK_ForwardEuler, AppAction)
50{
51 auto stepper = rcp(new Tempus::StepperERK_ForwardEuler<double>());
52 auto model = rcp(new Tempus_Test::SinCosModel<double>());
53 testRKAppAction(stepper, model, out, success);
54}
55
56
57// ************************************************************
58// ************************************************************
59TEUCHOS_UNIT_TEST(ERK_ForwardEuler, FSAL)
60{
61 auto stepper = rcp(new Tempus::StepperERK_ForwardEuler<double>());
62 Teuchos::RCP<const Thyra::ModelEvaluator<double> >
63 model = rcp(new Tempus_Test::DahlquistTestModel<double>(-1.0, true));
64
65 stepper->setModel(model);
66 stepper->setICConsistency("Consistent");
67 stepper->setUseFSAL(true);
68 stepper->initialize();
69
70 // Create a SolutionHistory.
71 auto solutionHistory = Tempus::createSolutionHistoryME(model);
72
73 // Take one time step.
74 stepper->setInitialConditions(solutionHistory);
75 solutionHistory->initWorkingState();
76 double dt = 1.0;
77 solutionHistory->getWorkingState()->setTimeStep(dt);
78 solutionHistory->getWorkingState()->setTime(dt);
79 stepper->takeStep(solutionHistory);
80
81 // Test solution.
82 const double relTol = 1.0e-14;
83
84 // ICs
85 auto currentState = solutionHistory->getCurrentState();
86 const double x_0 = get_ele(*(currentState->getX()), 0);
87 const double xDot_0 = get_ele(*(currentState->getXDot()), 0);
88 TEST_FLOATING_EQUALITY(x_0, 1.0, relTol);
89 TEST_FLOATING_EQUALITY(xDot_0, -1.0, relTol);
90 TEST_ASSERT(std::abs(currentState->getTime()) < relTol);
91
92 // After one step.
93 auto workingState = solutionHistory->getWorkingState();
94 const double x_1 = get_ele(*(workingState->getX()), 0);
95 const double xDot_1 = get_ele(*(workingState->getXDot()), 0);
96 //out << "xDot_1 = " << xDot_1 << std::endl;
97 TEST_ASSERT(std::abs(x_1 ) < relTol);
98 TEST_ASSERT(std::abs(xDot_1) < relTol);
99 TEST_FLOATING_EQUALITY(workingState->getTime(), 1.0, relTol);
100
101}
102
103
104} // namespace Tempus_Test
Forward Euler Runge-Kutta Butcher Tableau.
The classic Dahlquist Test Problem.
Sine-Cosine model problem from Rythmos. This is a canonical Sine-Cosine differential equation.
void testExplicitRKAccessorsFullConstruction(const RCP< Tempus::StepperExplicitRK< double > > &stepper)
Unit test utility for ExplicitRK Stepper construction and accessors.
void testRKAppAction(const Teuchos::RCP< Tempus::StepperRKBase< double > > &stepper, const Teuchos::RCP< const Thyra::ModelEvaluator< double > > &model, Teuchos::FancyOStream &out, bool &success)
Unit test utility for Stepper RK AppAction.
TEUCHOS_UNIT_TEST(BackwardEuler, Default_Construction)
void testFactoryConstruction(std::string stepperType, const Teuchos::RCP< const Thyra::ModelEvaluator< double > > &model)
Unit test utility for Stepper construction through StepperFactory.
Teuchos::RCP< SolutionHistory< Scalar > > createSolutionHistoryME(const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &model)
Nonmember contructor from a Thyra ModelEvaluator.