Nektar::LibUtilities::NekNonlinSysNewton Class Reference

#include <NekNonlinSysNewton.h>

Inheritance diagram for Nektar::LibUtilities::NekNonlinSysNewton:

Public Member Functions
	NekNonlinSysNewton (const LibUtilities::SessionReaderSharedPtr &pSession, const LibUtilities::CommSharedPtr &vRowComm, const int nscale, const NekSysKey &pKey)
	~NekNonlinSysNewton ()
Public Member Functions inherited from Nektar::LibUtilities::NekNonlinSys
	NekNonlinSys (const LibUtilities::SessionReaderSharedPtr &pSession, const LibUtilities::CommSharedPtr &vRowComm, const int nDimen, const NekSysKey &pKey)
	~NekNonlinSys ()
const Array< OneD, const NekDouble > &	GetRefSolution () const
const Array< OneD, const NekDouble > &	GetRefResidual () const
const Array< OneD, const NekDouble > &	GetRefSourceVec () const
void	SetNekNonlinSysTolerance (const NekDouble in)
void	SetNekNonlinSysMaxIterations (const unsigned int in)
const NekLinSysIterSharedPtr &	GetLinSys ()
void	SetNonlinIterTolRelativeL2 (const NekDouble in)
void	SetLinSysRelativeTolInNonlin (const NekDouble in)
int	GetNtotLinSysIts ()
void	SetupNekNonlinSystem (const int nGlobal, const Array< OneD, const NekDouble > &pInput, const Array< OneD, const NekDouble > &pSource, const int nDir)
Public Member Functions inherited from Nektar::LibUtilities::NekSys
	NekSys (const LibUtilities::SessionReaderSharedPtr &pSession, const LibUtilities::CommSharedPtr &vRowComm, const int nDimen, const NekSysKey &pKey)
void	InitObject ()
virtual	~NekSys ()
void	SetSysOperators (const NekSysOperators &in)
const NekSysOperators &	GetSysOperators ()
int	SolveSystem (const int nGlobal, const Array< OneD, const NekDouble > &pInput, Array< OneD, NekDouble > &pOutput, const int nDir, const NekDouble tol=1.0E-7, const NekDouble factor=1.0)
bool	ConvergenceCheck (const int nIteration, const Array< OneD, const NekDouble > &Residual, const NekDouble tol=1.0E-7)
void	SetFlagWarnings (bool in)

Static Public Member Functions
static NekNonlinSysSharedPtr	create (const LibUtilities::SessionReaderSharedPtr &pSession, const LibUtilities::CommSharedPtr &vRowComm, const int nDimen, const NekSysKey &pKey)
Static Public Member Functions inherited from Nektar::LibUtilities::NekSys
static NekSysSharedPtr	CreateInstance (const LibUtilities::SessionReaderSharedPtr &pSession, const LibUtilities::CommSharedPtr &vRowComm, const int nDimen, const NekSysKey &pKey)

Static Public Attributes
static std::string	className

Protected Member Functions
virtual void	v_InitObject () override
virtual int	v_SolveSystem (const int nGlobal, const Array< OneD, const NekDouble > &pInput, Array< OneD, NekDouble > &pOutput, const int nDir, const NekDouble tol, const NekDouble factor) override
virtual bool	v_ConvergenceCheck (const int nIteration, const Array< OneD, const NekDouble > &Residual, const NekDouble tol) override
virtual void	v_SetupNekNonlinSystem (const int nGlobal, const Array< OneD, const NekDouble > &pInput, const Array< OneD, const NekDouble > &pSource, const int nDir) override
virtual void	v_InitObject ()
virtual void	v_SetupNekNonlinSystem (const int nGlobal, const Array< OneD, const NekDouble > &pInput, const Array< OneD, const NekDouble > &pSource, const int nDir)=0
Protected Member Functions inherited from Nektar::LibUtilities::NekSys
virtual void	v_InitObject ()
virtual int	v_SolveSystem (const int nGlobal, const Array< OneD, const NekDouble > &pInput, Array< OneD, NekDouble > &pOutput, const int nDir, const NekDouble tol, const NekDouble factor)
virtual bool	v_ConvergenceCheck (const int nIteration, const Array< OneD, const NekDouble > &Residual, const NekDouble tol)
virtual void	v_NekSysInitialGuess (const Array< OneD, const NekDouble > &pInput, Array< OneD, NekDouble > &pguess)

Protected Attributes
NekDouble	m_SysResNorm0
NekDouble	m_SysResNorm
bool	m_InexactNewtonForcing = 0
NekDouble	m_forcingGamma = 1.0
NekDouble	m_forcingAlpha = 0.5 * (1.0 + sqrt(5))
Protected Attributes inherited from Nektar::LibUtilities::NekNonlinSys
NekLinSysIterSharedPtr	m_linsol
NekDouble	m_NonlinIterTolRelativeL2
NekDouble	m_LinSysRelativeTolInNonlin
std::string	m_LinSysIterSolverType
int	m_totalIterations = 0
int	m_NtotLinSysIts = 0
Array< OneD, NekDouble >	m_Solution
Array< OneD, NekDouble >	m_Residual
Array< OneD, NekDouble >	m_DeltSltn
Array< OneD, NekDouble >	m_SourceVec
Protected Attributes inherited from Nektar::LibUtilities::NekSys
int	m_maxiter
	Maximum iterations. More...
NekDouble	m_tolerance
	Tolerance of iterative solver. More...
LibUtilities::CommSharedPtr	m_rowComm
	Communicate. More...
bool	m_converged
	Whether the iteration has been converged. More...
bool	m_root
	Root if parallel. More...
bool	m_verbose
	Verbose. More...
bool	m_FlagWarnings
NekSysOperators	m_operator
	Operators. More...
int	m_SysDimen
	The dimension of the system. More...

Private Member Functions
NekDouble	CalcInexactNewtonForcing (const int &k, const NekDouble &resnormOld, const NekDouble &resnorm)

Friends
class	MemoryManager< NekNonlinSysNewton >
	Constructor for full direct matrix solve. More...

Detailed Description

Solves a nonlinear system using iterative methods.

Definition at line 48 of file NekNonlinSysNewton.h.

Constructor & Destructor Documentation

NekNonlinSysNewton()

Nektar::LibUtilities::NekNonlinSysNewton::NekNonlinSysNewton	(	const LibUtilities::SessionReaderSharedPtr &	pSession,
		const LibUtilities::CommSharedPtr &	vRowComm,
		const int	nscale,
		const NekSysKey &	pKey
	)

Definition at line 54 of file NekNonlinSysNewton.cpp.

    : NekNonlinSys(pSession, vRowComm, nscale, pKey)
{
}

~NekNonlinSysNewton()

Nektar::LibUtilities::NekNonlinSysNewton::~NekNonlinSysNewton

(

)

Definition at line 69 of file NekNonlinSysNewton.cpp.

{
}

Member Function Documentation

CalcInexactNewtonForcing()

NekDouble Nektar::LibUtilities::NekNonlinSysNewton::CalcInexactNewtonForcing ( const int &  k, const NekDouble &  resnormOld, const NekDouble &  resnorm  )

private

Definition at line 162 of file NekNonlinSysNewton.cpp.

{
    if (k == 0 || !m_InexactNewtonForcing)
    {
        return m_LinSysRelativeTolInNonlin;
    }
    else
    {
        NekDouble tmpForc =
            m_forcingGamma * pow((resnorm / resnormOld), m_forcingAlpha);
        return max(min(m_LinSysRelativeTolInNonlin, tmpForc), 1.0E-6);
    }
}

References m_forcingAlpha, m_forcingGamma, m_InexactNewtonForcing, and Nektar::LibUtilities::NekNonlinSys::m_LinSysRelativeTolInNonlin.

Referenced by v_SolveSystem().

create()

static NekNonlinSysSharedPtr Nektar::LibUtilities::NekNonlinSysNewton::create ( const LibUtilities::SessionReaderSharedPtr &  pSession, const LibUtilities::CommSharedPtr &  vRowComm, const int  nDimen, const NekSysKey &  pKey  )

inlinestatic

Definition at line 54 of file NekNonlinSysNewton.h.

    {
        NekNonlinSysSharedPtr p =
            MemoryManager<NekNonlinSysNewton>::AllocateSharedPtr(
                pSession, vRowComm, nDimen, pKey);
        p->InitObject();
        return p;
    }

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

v_ConvergenceCheck()

bool Nektar::LibUtilities::NekNonlinSysNewton::v_ConvergenceCheck ( const int  nIteration, const Array< OneD, const NekDouble > &  Residual, const NekDouble  tol  )

overrideprotectedvirtual

Reimplemented from Nektar::LibUtilities::NekSys.

Definition at line 132 of file NekNonlinSysNewton.cpp.

{
    bool converged     = false;
    NekDouble resratio = 1.0;
    int ntotal         = Residual.size();
 
    m_SysResNorm = Vmath::Dot(ntotal, Residual, Residual);
    m_rowComm->AllReduce(m_SysResNorm, Nektar::LibUtilities::ReduceSum);
 
    if (nIteration == 0)
    {
        m_SysResNorm0 = m_SysResNorm;
        resratio      = 1.0;
    }
    else
    {
        resratio = m_SysResNorm / m_SysResNorm0;
    }
 
    if (resratio < (m_NonlinIterTolRelativeL2 * m_NonlinIterTolRelativeL2) ||
        m_SysResNorm < tol * tol)
    {
        converged = true;
    }
 
    return converged;
}

References Vmath::Dot(), Nektar::LibUtilities::NekNonlinSys::m_NonlinIterTolRelativeL2, Nektar::LibUtilities::NekSys::m_rowComm, m_SysResNorm, m_SysResNorm0, and Nektar::LibUtilities::ReduceSum.

Referenced by v_SolveSystem().

v_InitObject()

void Nektar::LibUtilities::NekNonlinSysNewton::v_InitObject ( )

overrideprotectedvirtual

Reimplemented from Nektar::LibUtilities::NekNonlinSys.

Definition at line 62 of file NekNonlinSysNewton.cpp.

{
    NekSys::v_InitObject();
    m_Residual = Array<OneD, NekDouble>(m_SysDimen, 0.0);
    m_DeltSltn = Array<OneD, NekDouble>(m_SysDimen, 0.0);
}

References Nektar::LibUtilities::NekNonlinSys::m_DeltSltn, Nektar::LibUtilities::NekNonlinSys::m_Residual, Nektar::LibUtilities::NekSys::m_SysDimen, and Nektar::LibUtilities::NekSys::v_InitObject().

v_SetupNekNonlinSystem()

void Nektar::LibUtilities::NekNonlinSysNewton::v_SetupNekNonlinSystem ( const int  nGlobal, const Array< OneD, const NekDouble > &  pInput, const Array< OneD, const NekDouble > &  pSource, const int  nDir  )

overrideprotectedvirtual

Implements Nektar::LibUtilities::NekNonlinSys.

Definition at line 177 of file NekNonlinSysNewton.cpp.

{
    boost::ignore_unused(pInput);
 
    ASSERTL0(0 == nDir, "0 != nDir not tested");
    ASSERTL0(m_SysDimen == nGlobal, "m_SysDimen!=nGlobal");
 
    m_SourceVec = pSource;
 
    m_linsol->SetSysOperators(m_operator);
}

References ASSERTL0, Nektar::LibUtilities::NekNonlinSys::m_linsol, Nektar::LibUtilities::NekSys::m_operator, Nektar::LibUtilities::NekNonlinSys::m_SourceVec, and Nektar::LibUtilities::NekSys::m_SysDimen.

Referenced by v_SolveSystem().

v_SolveSystem()

int Nektar::LibUtilities::NekNonlinSysNewton::v_SolveSystem ( const int  nGlobal, const Array< OneD, const NekDouble > &  pInput, Array< OneD, NekDouble > &  pOutput, const int  nDir, const NekDouble  tol, const NekDouble  factor  )

overrideprotectedvirtual

Reimplemented from Nektar::LibUtilities::NekSys.

Definition at line 76 of file NekNonlinSysNewton.cpp.

{
    boost::ignore_unused(factor);
 
    v_SetupNekNonlinSystem(nGlobal, pInput, pInput, nDir);
 
    m_Solution = pOutput;
    Vmath::Vcopy(nGlobal - nDir, pInput, 1, m_Solution, 1);
 
    int ntotal      = nGlobal - nDir;
    m_NtotLinSysIts = 0;
    m_converged     = false;
 
    NekDouble resnormOld = 0.0;
    int NttlNonlinIte    = 0;
    for (; NttlNonlinIte < m_maxiter; ++NttlNonlinIte)
    {
        m_operator.DoNekSysResEval(m_Solution, m_Residual);
 
        m_converged = v_ConvergenceCheck(NttlNonlinIte, m_Residual, tol);
        if (m_converged)
        {
            break;
        }
 
        NekDouble LinSysRelativeIteTol =
            CalcInexactNewtonForcing(NttlNonlinIte, resnormOld, m_SysResNorm);
        NekDouble LinSysTol = LinSysRelativeIteTol * sqrt(m_SysResNorm);
        resnormOld          = m_SysResNorm;
 
        int ntmpLinSysIts =
            m_linsol->SolveSystem(ntotal, m_Residual, m_DeltSltn, 0, LinSysTol);
        m_NtotLinSysIts += ntmpLinSysIts;
 
        Vmath::Vsub(ntotal, m_Solution, 1, m_DeltSltn, 1, m_Solution, 1);
    }
 
    if (((!m_converged) || m_verbose) && m_root && m_FlagWarnings)
    {
        int nwidthcolm = 11;
 
        WARNINGL0(m_converged,
                  "     # Nonlinear solver not converge in DoImplicitSolve");
        cout << right << scientific << setw(nwidthcolm)
             << setprecision(nwidthcolm - 6)
             << "     * Newton-Its converged (RES=" << sqrt(m_SysResNorm)
             << " Res/(DtRHS): " << sqrt(m_SysResNorm / m_SysResNorm0)
             << " with " << setw(3) << NttlNonlinIte << " Non-Its)" << endl;
    }
 
    return NttlNonlinIte;
}

References CalcInexactNewtonForcing(), Nektar::LibUtilities::NekSysOperators::DoNekSysResEval(), Nektar::LibUtilities::NekSys::m_converged, Nektar::LibUtilities::NekNonlinSys::m_DeltSltn, Nektar::LibUtilities::NekSys::m_FlagWarnings, Nektar::LibUtilities::NekNonlinSys::m_linsol, Nektar::LibUtilities::NekSys::m_maxiter, Nektar::LibUtilities::NekNonlinSys::m_NtotLinSysIts, Nektar::LibUtilities::NekSys::m_operator, Nektar::LibUtilities::NekNonlinSys::m_Residual, Nektar::LibUtilities::NekSys::m_root, Nektar::LibUtilities::NekNonlinSys::m_Solution, m_SysResNorm, m_SysResNorm0, Nektar::LibUtilities::NekSys::m_verbose, tinysimd::sqrt(), v_ConvergenceCheck(), v_SetupNekNonlinSystem(), Vmath::Vcopy(), Vmath::Vsub(), and WARNINGL0.

Friends And Related Function Documentation

MemoryManager< NekNonlinSysNewton >

friend class MemoryManager< NekNonlinSysNewton >

friend

Constructor for full direct matrix solve.

Definition at line 1 of file NekNonlinSysNewton.h.

Member Data Documentation

className

string Nektar::LibUtilities::NekNonlinSysNewton::className

static

Initial value:

=
    LibUtilities::GetNekNonlinSysFactory().RegisterCreatorFunction(
        "Newton", NekNonlinSysNewton::create, "NekNonlinSysNewton solver.")

Definition at line 66 of file NekNonlinSysNewton.h.

m_forcingAlpha

NekDouble Nektar::LibUtilities::NekNonlinSysNewton::m_forcingAlpha = 0.5 * (1.0 + sqrt(5))

protected

Definition at line 79 of file NekNonlinSysNewton.h.

Referenced by CalcInexactNewtonForcing().

m_forcingGamma

NekDouble Nektar::LibUtilities::NekNonlinSysNewton::m_forcingGamma = 1.0

protected

Definition at line 78 of file NekNonlinSysNewton.h.

Referenced by CalcInexactNewtonForcing().

m_InexactNewtonForcing

bool Nektar::LibUtilities::NekNonlinSysNewton::m_InexactNewtonForcing = 0

protected

Definition at line 77 of file NekNonlinSysNewton.h.

Referenced by CalcInexactNewtonForcing().

m_SysResNorm

NekDouble Nektar::LibUtilities::NekNonlinSysNewton::m_SysResNorm

protected

Definition at line 75 of file NekNonlinSysNewton.h.

Referenced by v_ConvergenceCheck(), and v_SolveSystem().

m_SysResNorm0

NekDouble Nektar::LibUtilities::NekNonlinSysNewton::m_SysResNorm0

protected

Definition at line 74 of file NekNonlinSysNewton.h.

Referenced by v_ConvergenceCheck(), and v_SolveSystem().