Nonlinear quasi-static solution driver for isogeometric FEM simulators. More...

#include <NonLinSIM.h>

Inheritance diagram for NonLinSIM:

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Collaboration diagram for NonLinSIM:

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Public Types
enum	CNORM { NONE_UPTAN =-1 , NONE =0 , L2 =1 , L2SOL =2 , ENERGY =3 }
	Enum describing the norm used for convergence checks. More...

Public Types inherited from MultiStepSIM
enum	SubIt { ITER = 0 , FIRST = 1 , LAST = 2 , NONE = 3 }
	Enum describing sub-iteration status.

Public Member Functions
	NonLinSIM (SIMbase &sim, CNORM n=ENERGY)
	The constructor initializes default solution parameters. More...

virtual	~NonLinSIM ()
	The destructor prints out the slow-converging nodes, if any.

void	setConvNorm (CNORM n)
	Defines which type of iteration norm to use in convergence checks.

void	init (size_t nSol, const RealArray &initVal)
	Initializes the primary solution vectors. More...

virtual void	initPrm ()
	Initializes some integration parameters for the integrand.

virtual bool	advanceStep (TimeStep &param, bool updateTime=true)
	Advances the load step one step forward. More...

SIM::ConvStatus	solve (double zero_tol=1.0e-8, std::streamsize outPrec=0)
	Solves the nonlinear equations by Newton-Raphson iterations. More...

virtual SIM::ConvStatus	solveStep (TimeStep &param, SIM::SolutionMode mode=SIM::STATIC, double zero_tolerance=1.0e-8, std::streamsize outPrec=0)
	Solves the nonlinear equations by Newton-Raphson iterations. More...

SIM::ConvStatus	solveIteration (TimeStep &param)
	Solves the linearized system of current iteration. More...

int	getMaxit () const
	Returns the maximum number of iterations.

virtual bool	isLinear () const
	Returns whether this solution driver is linear or not.

virtual bool	parse (char *keyWord, std::istream &is)
	Parses a data section from an input stream. More...

virtual bool	parse (const tinyxml2::XMLElement *elem)
	Parses a data section from an XML document. More...

Public Member Functions inherited from MultiStepSIM
virtual void	printProblem (bool stopInputTimer=false) const
	Prints out problem-specific data to the log stream. More...

virtual const char **	getPrioritizedTags () const
	Returns a list of prioritized XML-tags.

virtual void	initSol (size_t nSol=1, size_t nDof=0)
	Initializes the primary solution vectors. More...

bool	initEqSystem (bool withRF=true, size_t nScl=0)
	Allocates the FE system matrices. More...

virtual bool	preprocess (const std::vector< int > &ignored, bool fixDup)
	Performs some pre-processing tasks on the FE model. More...

void	setStartGeo (int gID)
	Initializes the geometry block counter.

bool	saveModel (const char *fileName)
	Opens a new VTF-file and writes the model geometry to it. More...

bool	saveModel (int &gBlock, int &rBlock, const char *fileName=nullptr, bool clearG=true)
	Opens a new VTF-file and writes the model geometry to it. More...

bool	saveModel (int &gBlock, int &rBlock, double time)
	Writes the model geometry and BCs to an already opened VTF-file. More...

bool	saveStep (int iStep, double time, const char *vecName=nullptr)
	Saves the converged solution to VTF file of a given time/load step. More...

bool	saveStep (int iStep, int &rBlock, double time, const char *vecName=nullptr)
	Saves the converged solution to VTF file of a given time/load step. More...

bool	saveStep (int iStep, int &rBlock, const char *vecName)
	Saves the converged solution to VTF file of a given time/load step. More...

virtual bool	serialize (SerializeMap &data) const
	Serializes the solution vectors for restarting purposes. More...

virtual bool	deSerialize (const SerializeMap &data)
	Restores the solution vectors from a serialized state. More...

bool	checkForRestart ()
	Restores the solution from a serialized state in case of restart.

void	dumpStep (int iStep, double time, utl::LogStream &os, bool withID=true) const
	Dumps the primary solution for inspection. More...

virtual void	dumpResults (double time, utl::LogStream &os, std::streamsize precision=3, bool formatted=true) const
	Dumps solution variables at user-defined points. More...

bool	hasPointResultFile () const
	Returns whether a points result file has been defined or not.

bool	savePoints (double time, int step) const
	Saves point-wise solution to file for a given time/load step. More...

virtual bool	isDynamic () const
	Returns whether this is a dynamic solution driver or not.

const SIMoutput &	getModel () const
	Returns a const reference to the FE model.

void	setSubIteration (SubIt flag)
	Updates the sub-iteration flag.

SubIt	getSubIteration () const
	Returns the sub-iteration flag.

virtual size_t	numSolution () const
	Returns the number of solution vectors.

virtual const Vector &	realSolution (int i=0) const
	Returns a const reference to the current real solution vector. More...

virtual const Vectors &	realSolutions (bool=false)
	Returns a const reference to the current real solution vectors. More...

double *	theRefNorm ()
	Returns a pointer to the reference norm variable.

const double *	getRefNorm () const
	Returns a const pointer to the reference norm variable.

virtual bool	parse (char *keyWord, std::istream &is)
	Parses a data section from an input stream.

virtual bool	parse (const tinyxml2::XMLElement *elem)
	Parses a data section from an XML document.

Public Member Functions inherited from SIMsolution
virtual const Vectors &	getSolutions () const
	Returns a const reference to the solution vectors.

virtual Vectors &	theSolutions ()
	Returns a reference to the solution vectors (for assignment).

virtual const Vector &	getSolution (int ix=0) const
	Returns a const reference to current solution vector.

virtual void	setSolution (const RealArray &s, int ix=0)
	Modifies the current solution vector (used by sub-iterations only).

Public Member Functions inherited from SIMadmin
virtual	~SIMadmin ()
	Empty destructor.

virtual bool	read (const char *fileName)
	Reads model data from the specified input file *fileName.

virtual bool	preprocessC (const IntVec &, bool, double=0.0)
	Performs some pre-processing tasks on the FE model.

const ProcessAdm &	getProcessAdm () const
	Returns the parallel process administrator.

int	getGlobalProcessID () const
	Returns the global process ID. More...

const std::string &	getHeading () const
	Returns the simulator heading.

void	setHeading (const std::string &heading)
	Defines the simulator heading.

void	printHeading (int &supStep) const
	Prints the heading of this simulator, if any, to IFEM::cout.

Public Member Functions inherited from XMLInputBase
bool	readXML (const char *fileName, bool verbose=true)
	Reads an XML input file. More...

bool	loadXML (const char *xml)
	Loads data from an XML-formatted text string. More...

Static Public Attributes
static const char *	inputContext = "nonlinearsolver"
	Input file context for solver parameters.

Static Public Attributes inherited from SIMadmin
static int	msgLevel = 2
	Controls the console output amount during solving.

Protected Member Functions
void	printWorst (utl::LogStream &os, double eps)
	Prints out the worst DOFs when slow convergence is detected. More...

virtual SIM::ConvStatus	checkConvergence (TimeStep &param)
	Checks whether the nonlinear iterations have converged or diverged.

virtual bool	updateConfiguration (TimeStep &param)
	Updates configuration variables (solution vector) in an iteration.

virtual bool	lineSearch (TimeStep &param)
	Performs line search to accelerate convergence. More...

virtual bool	assembleSystem (const TimeDomain &time, const Vectors &pSol, bool newLHSmatrix=true, bool poorConvg=false)
	Administers assembly of the linear equation system. More...

Protected Member Functions inherited from MultiStepSIM
	MultiStepSIM (SIMbase &sim)
	The constructor initializes the FE model reference. More...

void	printStep (const TimeStep &param) const
	Prints out time/load step identification. More...

virtual bool	solutionNorms (const TimeDomain &, double zero_tolerance=1.0e-8, std::streamsize outPrec=0)
	Computes and prints some solution norm quantities. More...

int	getLastSavedStep () const
	Returns the last step that was saved to VTF.

Protected Member Functions inherited from SIMsolution
	SIMsolution ()=default
	The default constructor is protected to allow sub-classes only.

virtual	~SIMsolution ()=default
	Empty default destructor.

void	initSolution (size_t ndof, size_t nsol=1)
	Initializes the solution vectors. More...

void	pushSolution (unsigned short int nVecState=1)
	Pushes the solution vector stack. More...

bool	saveSolution (SerializeMap &data, const std::string &name) const
	Writes current solution to a serialization container. More...

bool	restoreSolution (const SerializeMap &data, const std::string &name)
	Restores the solution from a serialization container. More...

Protected Member Functions inherited from SIMadmin
	SIMadmin (const char *heading=nullptr)
	The default constructor initializes the process administrator.

	SIMadmin (SIMadmin &anotherSIM)
	Copy constructor.

Protected Member Functions inherited from XMLInputBase
const tinyxml2::XMLElement *	loadFile (tinyxml2::XMLDocument &doc, const char *fileName, bool verbose=false)
	Loads an XML input file into a tinyxml2::XMLDocument object. More...

Protected Attributes
bool	fromIni
	If true, always solve from initial configuration.

CNORM	iteNorm
	The norm type used to measure the residual.

double	rTol
	Relative convergence tolerance.

double	aTol
	Absolute convergence tolerance.

double	divgLim
	Relative divergence limit.

double	eta
	Line search tolerance.

double	alpha
	Iteration acceleration parameter (for line search)

double	alphaO
	Final line search acceleration scaling (for output only)

int	maxit
	Maximum number of iterations in a load step.

int	maxIncr
	Maximum number of iterations with increasing norm.

int	nupdat
	Number of iterations with updated tangent.

int	prnSlow
	How many DOFs to print out on slow convergence.

bool	saveExL
	If true, the external load vector will be saved to VTF.

bool	updNewN
	If true, update newly activated nodes before new step.

std::map< int, int >	slowNodes
	Nodes for which slow convergence is detected.

Protected Attributes inherited from MultiStepSIM
SIMoutput &	model
	The isogeometric FE model.

Vector	loadVec
	System load vector (for output to VTF)

Vector	residual
	Residual force vector.

Vector	linsol
	Linear solution vector.

NormOp	refNopt
	Reference norm option.

double	refNorm
	Reference norm value used in convergence checks.

double	rCond
	Reciprocal condition number of the linear equation system.

SubIt	subiter
	Sub-iteration flag.

size_t	nRHSvec
	Number of right-hand-side vectors to assemble.

char	rotUpd
	Option for how to update of nodal rotations.

int	geoBlk
	Running VTF geometry block counter.

int	nBlock
	Running VTF result block counter.

Protected Attributes inherited from SIMsolution
Vectors	solution
	Stack of solution vectors.

Protected Attributes inherited from SIMadmin
ProcessAdm	adm
	Parallel administrator.

int	myPid
	Processor ID in parallel simulations.

int	nProc
	Number of processors in parallel simulations.

std::string	myHeading
	Heading written before reading the input file.

Additional Inherited Members
Public Attributes inherited from SIMadmin
SIMoptions &	opt
	Simulation control parameters.

Protected Types inherited from MultiStepSIM
enum	NormOp { MAX , ALL }
	Enum describing reference norm options.

Protected Types inherited from SIMsolution
using	SerializeMap = std::map< std::string, std::string >
	Convenience type.

Protected Types inherited from SIMadmin
using	IntVec = std::vector< int >
	Convenience alias.

Static Protected Member Functions inherited from SIMsolution
static std::string	serialize (const double *v, size_t n)
	Helper method for serializing a double array into a text string. More...

static void	deSerialize (const std::string &data, double *v, size_t n)
	Helper method for deserializing a double array from a text string. More...

Detailed Description

Nonlinear quasi-static solution driver for isogeometric FEM simulators.

This class contains data and methods for computing the nonlinear solution to a quasi-static FE problem based on splines/NURBS basis functions, through Newton-Raphson iterations.

Member Enumeration Documentation

◆ CNORM

enum NonLinSIM::CNORM

Enum describing the norm used for convergence checks.

The value NONE imples no checking at all and is used to conduct a pure linear analysis without equilibrium iterations. The value NONE_UPTAN value implies the same as NONE, but with recalculation of the tangent matrix at each step. This is needed for problems with inhomogeneous dirichlet conditions where the element tangent matrix is used to calculate the equivalent load vector.

Constructor & Destructor Documentation

◆ NonLinSIM()

NonLinSIM::NonLinSIM	(	SIMbase &	sim,
		CNORM	n = `ENERGY`
	)

explicit

The constructor initializes default solution parameters.

Parameters

	sim	Pointer to the spline FE model
[in]	n	Which type of iteration norm to use in convergence checks

References alpha, alphaO, aTol, divgLim, eta, fromIni, iteNorm, maxIncr, maxit, nupdat, prnSlow, rTol, saveExL, and updNewN.

Member Function Documentation

◆ advanceStep()

bool NonLinSIM::advanceStep	(	TimeStep &	param,
		bool	updateTime = `true`
	)

virtual

Advances the load step one step forward.

Parameters

	param	Time stepping parameters
[in]	updateTime	If false, the time parameters are not incremented

Reimplemented from MultiStepSIM.

References MultiStepSIM::advanceStep(), SIMbase::hasElementActivator(), MultiStepSIM::model, SIMsolution::pushSolution(), SIMsolution::solution, TimeStep::time, SIMbase::updateForNewElements(), and updNewN.

◆ assembleSystem()

bool NonLinSIM::assembleSystem	(	const TimeDomain &	time,
		const Vectors &	pSol,
		bool	newLHSmatrix = `true`,
		bool	poorConvg = `false`
	)

protectedvirtual

Administers assembly of the linear equation system.

Parameters

[in]	time	Parameters for nonlinear/time-dependent simulations
[in]	pSol	Previous primary solution vectors in DOF-order
[in]	newLHSmatrix	If false, only integrate the RHS vector
[in]	poorConvg	If true, the nonlinear driver is converging poorly

Reimplemented in TimeIntegration::SIMImplicitLMM< Solver >::LMMNonLinSIM.

References SIMbase::assembleSystem(), and MultiStepSIM::model.

Referenced by lineSearch(), and solveIteration().

◆ init()

void NonLinSIM::init	(	size_t	nSol,
		const RealArray &	initVal
	)

Initializes the primary solution vectors.

Parameters

[in]	nSol	Number of consequtive solutions stored in core
[in]	initVal	Initial values of the primary solution

References MultiStepSIM::initSol(), and SIMsolution::solution.

◆ lineSearch()

bool NonLinSIM::lineSearch ( TimeStep & param )

protectedvirtual

Performs line search to accelerate convergence.

This procedure is as described on pages 115,116 in Kjell Magne Mathisen's Dr.Ing. thesis: "Large displacement analysis of flexible and rigid systems considering displacement-dependent loads and nonlinear constraints", 1990.

References alpha, alphaO, assembleSystem(), utl::vector< T >::dot(), eta, SIMbase::extractLoadVec(), MultiStepSIM::linsol, MultiStepSIM::model, MultiStepSIM::residual, SIMbase::setMode(), SIMsolution::solution, TimeStep::time, and updateConfiguration().

Referenced by solveIteration().

◆ parse() [1/2]

bool NonLinSIM::parse	(	char *	keyWord,
		std::istream &	is
	)

virtual

Parses a data section from an input stream.

Parameters

[in]	keyWord	Keyword of current data section to read
	is	The file stream to read from

Reimplemented from SIMadmin.

References divgLim, eta, maxit, MultiStepSIM::model, nupdat, SIMoutput::parse(), utl::readLine(), and rTol.

◆ parse() [2/2]

bool NonLinSIM::parse ( const tinyxml2::XMLElement * elem )

virtual

Parses a data section from an XML document.

Parameters

[in] elem The XML element to parse

Reimplemented from MultiStepSIM.

References aTol, divgLim, eta, fromIni, utl::getAttribute(), utl::getValue(), inputContext, iteNorm, maxIncr, maxit, MultiStepSIM::model, nupdat, MultiStepSIM::parse(), SIMoutput::parse(), prnSlow, MultiStepSIM::rCond, MultiStepSIM::refNopt, MultiStepSIM::rotUpd, rTol, saveExL, and updNewN.

◆ printWorst()

void NonLinSIM::printWorst	(	utl::LogStream &	os,
		double	eps
	)

protected

Prints out the worst DOFs when slow convergence is detected.

Parameters

	os	The output stream to print to
[in]	eps	Only print DOF values larger than this tolerance

References SIMbase::getNodeType(), SIMbase::getWorstDofs(), iteNorm, MultiStepSIM::linsol, MultiStepSIM::model, prnSlow, MultiStepSIM::residual, and slowNodes.

◆ solve()

ConvStatus NonLinSIM::solve	(	double	zero_tol = `1.0e-8`,
		std::streamsize	outPrec = `0`
	)

Solves the nonlinear equations by Newton-Raphson iterations.

Parameters

[in]	zero_tol	Truncate norm values smaller than this to zero
[in]	outPrec	Number of digits after the decimal point in norm print

References solveStep().

◆ solveIteration()

SIM::ConvStatus NonLinSIM::solveIteration ( TimeStep & param )

Solves the linearized system of current iteration.

Parameters

[in] param Time stepping parameters

References assembleSystem(), checkConvergence(), SIMbase::extractLoadVec(), TimeStep::iter, lineSearch(), MultiStepSIM::linsol, MultiStepSIM::model, SIMadmin::msgLevel, nupdat, MultiStepSIM::rCond, MultiStepSIM::residual, SIMbase::setMode(), SIMsolution::solution, MultiStepSIM::solutionNorms(), SIMbase::solveEqSystem(), TimeDomain::t, TimeStep::time, updateConfiguration(), and SIMbase::updateDirichlet().

◆ solveStep()

ConvStatus NonLinSIM::solveStep	(	TimeStep &	param,
		SIM::SolutionMode	mode = `SIM::STATIC`,
		double	zero_tolerance = `1.0e-8`,
		std::streamsize	outPrec = `0`
	)

virtual

Solves the nonlinear equations by Newton-Raphson iterations.

Parameters

	param	Time stepping parameters
[in]	mode	Solution mode to use for this step
[in]	zero_tolerance	Truncate norm values smaller than this to zero
[in]	outPrec	Number of digits after the decimal point in norm print

Implements MultiStepSIM.

References PROFILE1, and SIMsolution::solution.

Referenced by solve(), and TimeIntegration::SIMImplicitLMM< Solver >::solveStep().

The documentation for this class was generated from the following files:

src/SIM/NonLinSIM.h
src/SIM/NonLinSIM.C

Public Types

Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ CNORM

Constructor & Destructor Documentation

◆ NonLinSIM()

Member Function Documentation

◆ advanceStep()

◆ assembleSystem()

◆ init()

◆ lineSearch()

◆ parse() [1/2]

◆ parse() [2/2]

◆ printWorst()

◆ solve()

◆ solveIteration()

◆ solveStep()