Nektar::LibUtilities::IMEXTimeIntegrationScheme Class Reference

#include <IMEXTimeIntegrationSchemes.h>

Inheritance diagram for Nektar::LibUtilities::IMEXTimeIntegrationScheme:

Public Member Functions
	IMEXTimeIntegrationScheme (std::string variant, size_t order, std::vector< NekDouble > freeParams)
	~IMEXTimeIntegrationScheme () override
Public Member Functions inherited from Nektar::LibUtilities::TimeIntegrationSchemeGLM
LUE void	InitializeSecondaryData (TimeIntegrationAlgorithmGLM *phase, NekDouble deltaT) const
Public Member Functions inherited from Nektar::LibUtilities::TimeIntegrationScheme
LUE std::string	GetFullName () const
LUE std::string	GetName () const
LUE std::string	GetVariant () const
LUE size_t	GetOrder () const
LUE std::vector< NekDouble >	GetFreeParams ()
LUE TimeIntegrationSchemeType	GetIntegrationSchemeType ()
LUE NekDouble	GetTimeStability () const
LUE size_t	GetNumIntegrationPhases ()
LUE const TripleArray &	GetSolutionVector () const
	Gets the solution vector of the ODE. More...
LUE TripleArray &	UpdateSolutionVector ()
LUE void	SetSolutionVector (const size_t Offset, const DoubleArray &y)
	Sets the solution vector of the ODE. More...
LUE void	InitializeScheme (const NekDouble deltaT, ConstDoubleArray &y_0, const NekDouble time, const TimeIntegrationSchemeOperators &op)
	Explicit integration of an ODE. More...
LUE ConstDoubleArray &	TimeIntegrate (const size_t timestep, const NekDouble delta_t)
LUE void	print (std::ostream &os) const
LUE void	printFull (std::ostream &os) const

Static Public Member Functions
static TimeIntegrationSchemeSharedPtr	create (std::string variant, size_t order, std::vector< NekDouble > freeParams)
static LUE void	SetupSchemeData (TimeIntegrationAlgorithmGLMSharedPtr &phase, size_t order)

Static Public Attributes
static std::string	className

Protected Member Functions
LUE std::string	v_GetFullName () const override
LUE std::string	v_GetName () const override
LUE NekDouble	v_GetTimeStability () const override
Protected Member Functions inherited from Nektar::LibUtilities::TimeIntegrationSchemeGLM
LUE std::string	v_GetVariant () const override
LUE size_t	v_GetOrder () const override
LUE std::vector< NekDouble >	v_GetFreeParams () const override
LUE TimeIntegrationSchemeType	v_GetIntegrationSchemeType () const override
LUE size_t	v_GetNumIntegrationPhases () const override
LUE const TripleArray &	v_GetSolutionVector () const override
LUE TripleArray &	v_UpdateSolutionVector () override
LUE void	v_SetSolutionVector (const size_t Offset, const DoubleArray &y) override
LUE void	v_InitializeScheme (const NekDouble deltaT, ConstDoubleArray &y_0, const NekDouble time, const TimeIntegrationSchemeOperators &op) override
	Worker method to initialize the integration scheme. More...
LUE ConstDoubleArray &	v_TimeIntegrate (const size_t timestep, const NekDouble delta_t) override
	Worker method that actually does the time integration. More...
virtual LUE void	v_InitializeSecondaryData (TimeIntegrationAlgorithmGLM *phase, NekDouble deltaT) const
LUE void	v_print (std::ostream &os) const override
	Worker method to print details on the integration scheme. More...
LUE void	v_printFull (std::ostream &os) const override
LUE	TimeIntegrationSchemeGLM (std::string variant, size_t order, std::vector< NekDouble > freeParams)
	~TimeIntegrationSchemeGLM () override
Protected Member Functions inherited from Nektar::LibUtilities::TimeIntegrationScheme
virtual LUE std::string	v_GetFullName () const
virtual LUE std::string	v_GetName () const =0
virtual LUE std::string	v_GetVariant () const =0
virtual LUE size_t	v_GetOrder () const =0
virtual LUE std::vector< NekDouble >	v_GetFreeParams () const =0
virtual LUE TimeIntegrationSchemeType	v_GetIntegrationSchemeType () const =0
virtual LUE NekDouble	v_GetTimeStability () const =0
virtual LUE size_t	v_GetNumIntegrationPhases () const =0
virtual LUE const TripleArray &	v_GetSolutionVector () const =0
virtual LUE TripleArray &	v_UpdateSolutionVector ()=0
virtual LUE void	v_SetSolutionVector (const size_t Offset, const DoubleArray &y)=0
virtual LUE void	v_InitializeScheme (const NekDouble deltaT, ConstDoubleArray &y_0, const NekDouble time, const TimeIntegrationSchemeOperators &op)=0
virtual LUE ConstDoubleArray &	v_TimeIntegrate (const size_t timestep, const NekDouble delta_t)=0
virtual LUE void	v_print (std::ostream &os) const =0
virtual LUE void	v_printFull (std::ostream &os) const =0
LUE	TimeIntegrationScheme (std::string variant, size_t order, std::vector< NekDouble > freeParams)
LUE	TimeIntegrationScheme (const TimeIntegrationScheme &in)=delete
virtual	~TimeIntegrationScheme ()=default

Additional Inherited Members
Protected Attributes inherited from Nektar::LibUtilities::TimeIntegrationSchemeGLM
TimeIntegrationAlgorithmGLMVector	m_integration_phases
TimeIntegrationSolutionGLMSharedPtr	m_solVector

Detailed Description

Definition at line 58 of file IMEXTimeIntegrationSchemes.h.

Constructor & Destructor Documentation

IMEXTimeIntegrationScheme()

Nektar::LibUtilities::IMEXTimeIntegrationScheme::IMEXTimeIntegrationScheme ( std::string  variant, size_t  order, std::vector< NekDouble >  freeParams  )

inline

Definition at line 61 of file IMEXTimeIntegrationSchemes.h.

        : TimeIntegrationSchemeGLM(variant, order, freeParams)
    {
        if (variant == "dirk" || variant == "DIRK")
        {
            ASSERTL1(freeParams.size() == 2,
                     "IMEX DIRK Time integration scheme invalid number "
                     "of free parameters, expected two "
                     "<implicit stages, explicit stages>, received " +
                         std::to_string(freeParams.size()));
 
            size_t s     = freeParams[0];
            size_t sigma = freeParams[1];
 
            m_integration_phases    = TimeIntegrationAlgorithmGLMVector(1);
            m_integration_phases[0] = TimeIntegrationAlgorithmGLMSharedPtr(
                new TimeIntegrationAlgorithmGLM(this));
 
            if (order == 1 && s == 1 && sigma == 1)
            {
                // This phase is Forward Backward Euler which has two steps.
                IMEXdirkTimeIntegrationScheme::SetupSchemeData_1_1_1(
                    m_integration_phases[0]);
            }
            else
            {
                IMEXdirkTimeIntegrationScheme::SetupSchemeData(
                    m_integration_phases[0], order, freeParams);
            }
        }
        else if (variant == "Gear")
        {
            m_integration_phases    = TimeIntegrationAlgorithmGLMVector(2);
            m_integration_phases[0] = TimeIntegrationAlgorithmGLMSharedPtr(
                new TimeIntegrationAlgorithmGLM(this));
            m_integration_phases[1] = TimeIntegrationAlgorithmGLMSharedPtr(
                new TimeIntegrationAlgorithmGLM(this));
 
            IMEXdirkTimeIntegrationScheme::SetupSchemeData(
                m_integration_phases[0], 2, std::vector<NekDouble>{2, 2});
            IMEXGearTimeIntegrationScheme::SetupSchemeData(
                m_integration_phases[1]);
        }
        else if (variant == "")
        {
            // Currently up to 4th order is implemented.
            ASSERTL1(1 <= order && order <= 4,
                     "IMEX Time integration scheme bad order (1-4): " +
                         std::to_string(order));
 
            m_integration_phases = TimeIntegrationAlgorithmGLMVector(order);
 
            for (size_t n = 0; n < order; ++n)
            {
                m_integration_phases[n] = TimeIntegrationAlgorithmGLMSharedPtr(
                    new TimeIntegrationAlgorithmGLM(this));
            }
 
            // Last phase
            IMEXTimeIntegrationScheme::SetupSchemeData(
                m_integration_phases[order - 1], order);
 
            // Initial phases
            switch (order)
            {
                case 1:
                    // No intial phase.
                    break;
 
                case 2:
                    IMEXTimeIntegrationScheme::SetupSchemeData(
                        m_integration_phases[0], 1);
                    break;
 
                case 3:
                    IMEXdirkTimeIntegrationScheme::SetupSchemeData(
                        m_integration_phases[0], 3,
                        std::vector<NekDouble>{3, 4});
                    IMEXdirkTimeIntegrationScheme::SetupSchemeData(
                        m_integration_phases[1], 3,
                        std::vector<NekDouble>{3, 4});
                    break;
 
                case 4:
                    IMEXdirkTimeIntegrationScheme::SetupSchemeData(
                        m_integration_phases[0], 3,
                        std::vector<NekDouble>{3, 4});
                    IMEXdirkTimeIntegrationScheme::SetupSchemeData(
                        m_integration_phases[1], 3,
                        std::vector<NekDouble>{3, 4});
                    IMEXdirkTimeIntegrationScheme::SetupSchemeData(
                        m_integration_phases[2], 3,
                        std::vector<NekDouble>{3, 4});
                    break;
 
                default:
                    ASSERTL1(false, "IMEX Time integration scheme bad order: " +
                                        std::to_string(order));
            }
        }
        else
        {
            ASSERTL1(false, "IMEX Time integration scheme bad variant: " +
                                variant + ". Must be blank, 'dirk' or 'Gear'");
        }
    }

References ASSERTL1, Nektar::LibUtilities::TimeIntegrationSchemeGLM::m_integration_phases, Nektar::LibUtilities::IMEXGearTimeIntegrationScheme::SetupSchemeData(), SetupSchemeData(), Nektar::LibUtilities::IMEXdirkTimeIntegrationScheme::SetupSchemeData(), and Nektar::LibUtilities::IMEXdirkTimeIntegrationScheme::SetupSchemeData_1_1_1().

~IMEXTimeIntegrationScheme()

Nektar::LibUtilities::IMEXTimeIntegrationScheme::~IMEXTimeIntegrationScheme ( )

inlineoverride

Definition at line 169 of file IMEXTimeIntegrationSchemes.h.

    {
    }

Member Function Documentation

create()

static TimeIntegrationSchemeSharedPtr Nektar::LibUtilities::IMEXTimeIntegrationScheme::create ( std::string  variant, size_t  order, std::vector< NekDouble >  freeParams  )

inlinestatic

Definition at line 173 of file IMEXTimeIntegrationSchemes.h.

    {
        TimeIntegrationSchemeSharedPtr p =
            MemoryManager<IMEXTimeIntegrationScheme>::AllocateSharedPtr(
                variant, order, freeParams);
 
        return p;
    }

References Nektar::MemoryManager< DataType >::AllocateSharedPtr(), and CellMLToNektar.cellml_metadata::p.

SetupSchemeData()

static LUE void Nektar::LibUtilities::IMEXTimeIntegrationScheme::SetupSchemeData ( TimeIntegrationAlgorithmGLMSharedPtr &  phase, size_t  order  )

inlinestatic

Definition at line 185 of file IMEXTimeIntegrationSchemes.h.

    {
        constexpr NekDouble ABcoefficients[5] = {0.,
                                                 1.,         // 1st Order
                                                 2. / 3.,    // 2nd Order
                                                 6. / 11.,   // 3rd Order
                                                 12. / 25.}; // 4th Order
 
        // Nsteps = 2 * order
 
        // clang-format off
        constexpr NekDouble UVcoefficients[5][8] =
            { {         0.,    0.,     0.,        0.,
                        0.,    0.,     0.,        0. },
              // 1st Order
              {         1.,    1.,     0.,        0.,
                        0.,    0.,     0.,        0. },
              // 2nd Order
              {  4./ 3.,  -1./ 3.,  4./3.,   -2./ 3.,
                 0.,           0.,     0.,        0. },
              // 3rd Order
              {  18./11.,  -9./11.,  2./11.,  18./11.,
                -18./11.,   6./11.,      0.,       0. },
              // 4th Order
              { 48./25., -36./25., 16./25.,  -3./25.,
                48./25., -72./25., 48./25., -12./25. } };
        // clang-format on
 
        phase->m_schemeType = eIMEX;
        phase->m_order      = order;
        phase->m_name =
            std::string("IMEXOrder" + std::to_string(phase->m_order));
 
        phase->m_numsteps  = 2 * phase->m_order;
        phase->m_numstages = 1;
 
        phase->m_A = Array<OneD, Array<TwoD, NekDouble>>(2);
        phase->m_B = Array<OneD, Array<TwoD, NekDouble>>(2);
 
        phase->m_A[0] =
            Array<TwoD, NekDouble>(phase->m_numstages, phase->m_numstages, 0.0);
        phase->m_B[0] =
            Array<TwoD, NekDouble>(phase->m_numsteps, phase->m_numstages, 0.0);
        phase->m_A[1] =
            Array<TwoD, NekDouble>(phase->m_numstages, phase->m_numstages, 0.0);
        phase->m_B[1] =
            Array<TwoD, NekDouble>(phase->m_numsteps, phase->m_numstages, 0.0);
        phase->m_U =
            Array<TwoD, NekDouble>(phase->m_numstages, phase->m_numsteps, 0.0);
        phase->m_V =
            Array<TwoD, NekDouble>(phase->m_numsteps, phase->m_numsteps, 0.0);
 
        // Coefficients
        phase->m_B[1][phase->m_order][0] = 1.0;
 
        phase->m_A[0][0][0] = ABcoefficients[phase->m_order];
        phase->m_B[0][0][0] = ABcoefficients[phase->m_order];
 
        for (size_t n = 0; n < 2 * phase->m_order; ++n)
        {
            phase->m_U[0][n] = UVcoefficients[phase->m_order][n];
            phase->m_V[0][n] = UVcoefficients[phase->m_order][n];
        }
 
        // V evaluation value shuffling row n column n-1
        for (size_t n = 1; n < 2 * phase->m_order; ++n)
        {
            if (n != phase->m_order)
            {
                phase->m_V[n][n - 1] = 1.0; // constant 1
            }
        }
 
        phase->m_numMultiStepValues         = phase->m_order;
        phase->m_numMultiStepImplicitDerivs = 0;
        phase->m_numMultiStepExplicitDerivs = phase->m_order;
 
        phase->m_timeLevelOffset = Array<OneD, size_t>(phase->m_numsteps);
 
        // Values and derivatives needed.
        for (size_t n = 0; n < phase->m_order; ++n)
        {
            phase->m_timeLevelOffset[n]                  = n;
            phase->m_timeLevelOffset[phase->m_order + n] = n;
        }
 
        phase->CheckAndVerify();
    }

References Nektar::LibUtilities::eIMEX.

Referenced by IMEXTimeIntegrationScheme().

v_GetFullName()

LUE std::string Nektar::LibUtilities::IMEXTimeIntegrationScheme::v_GetFullName ( ) const

inlineoverrideprotectedvirtual

Reimplemented from Nektar::LibUtilities::TimeIntegrationScheme.

Definition at line 276 of file IMEXTimeIntegrationSchemes.h.

    {
        return m_integration_phases.back()->m_name;
    }

References Nektar::LibUtilities::TimeIntegrationSchemeGLM::m_integration_phases.

v_GetName()

LUE std::string Nektar::LibUtilities::IMEXTimeIntegrationScheme::v_GetName ( ) const

inlineoverrideprotectedvirtual

Implements Nektar::LibUtilities::TimeIntegrationScheme.

Definition at line 281 of file IMEXTimeIntegrationSchemes.h.

    {
        return std::string("IMEX");
    }

v_GetTimeStability()

LUE NekDouble Nektar::LibUtilities::IMEXTimeIntegrationScheme::v_GetTimeStability ( ) const

inlineoverrideprotectedvirtual

Implements Nektar::LibUtilities::TimeIntegrationScheme.

Definition at line 286 of file IMEXTimeIntegrationSchemes.h.

    {
        return 1.0;
    }

Member Data Documentation

className

std::string Nektar::LibUtilities::IMEXTimeIntegrationScheme::className

static

Definition at line 183 of file IMEXTimeIntegrationSchemes.h.