Computes a dynamic mode decomposition model on a specified field. More...

Inheritance diagram for DMD:

Collaboration diagram for DMD:

Public Member Functions
	TypeName ("DMD")
	Runtime type information. More...

	DMD (const word &name, const Time &runTime, const dictionary &dict)
	Construct from Time and dictionary. More...

	DMD (const DMD &)=delete
	No copy construct. More...

void	operator= (const DMD &)=delete
	No copy assignment. More...

virtual	~DMD ()=default
	Destructor. More...

virtual bool	read (const dictionary &dict)
	Read DMD settings. More...

virtual bool	execute ()
	Execute DMD. More...

virtual bool	write ()
	Write DMD results. More...

virtual bool	end ()
	Write DMD results. More...

Public Member Functions inherited from fvMeshFunctionObject
	TypeName ("fvMeshFunctionObject")
	Runtime type information. More...

	fvMeshFunctionObject (const word &name, const Time &runTime, const dictionary &dict)
	Construct from Time and dictionary. More...

	fvMeshFunctionObject (const word &name, const objectRegistry &obr, const dictionary &dict)
	Construct from the region objectRegistry and dictionary. More...

virtual	~fvMeshFunctionObject ()=default
	Destructor. More...

Public Member Functions inherited from regionFunctionObject
	TypeName ("regionFunctionObject")
	Runtime type information. More...

	regionFunctionObject (const word &name, const Time &runTime, const dictionary &dict)
	Construct from Time and dictionary. More...

	regionFunctionObject (const word &name, const objectRegistry &obr, const dictionary &dict)
	Construct from the region objectRegistry and dictionary. More...

virtual	~regionFunctionObject ()=default
	Destructor. More...

virtual bool	read (const dictionary &dict)
	Read optional controls. More...

template<class ObjectType >
const ObjectType *	lookupObjectPtr (const word &fieldName) const
	Deprecated(2018-10) More...

template<class ObjectType >
ObjectType *	lookupObjectRefPtr (const word &fieldName) const
	Deprecated(2018-10) More...

Public Member Functions inherited from stateFunctionObject
	stateFunctionObject (const word &name, const Time &runTime)
	Construct from components. More...

virtual	~stateFunctionObject ()=default
	Destructor. More...

dictionary &	propertyDict ()
	Return access to the property dictionary. More...

bool	foundProperty (const word &entryName) const
	Return true if the property exists. More...

void	clearTrigger ()
	Remove the trigger index from the properties. More...

label	getTrigger () const
	Get the current trigger index. More...

bool	setTrigger (const label triggeri)
	Set new trigger index. More...

bool	getDict (const word &entryName, dictionary &dict) const
	Set dictionary, return true if set. More...

bool	getObjectDict (const word &objectName, const word &entryName, dictionary &dict) const
	Set dictionary from named object, return true if set. More...

template<class Type >
Type	getProperty (const word &entryName, const Type &defaultValue=Type(Zero)) const
	Retrieve generic property. More...

template<class Type >
bool	getProperty (const word &entryName, Type &value) const
	Set generic property, return true if set. More...

template<class Type >
void	setProperty (const word &entryName, const Type &value)
	Add generic property. More...

template<class Type >
Type	getObjectProperty (const word &objectName, const word &entryName, const Type &defaultValue=Type(Zero)) const
	Retrieve generic property from named object. More...

template<class Type >
bool	getObjectProperty (const word &objectName, const word &entryName, Type &value) const
	Set generic property from named object, return true if set. More...

template<class Type >
void	setObjectProperty (const word &objectName, const word &entryName, const Type &value)
	Add generic property from named object. More...

template<class Type >
void	setResult (const word &entryName, const Type &value)
	Add result. More...

template<class Type >
void	setObjectResult (const word &objectName, const word &entryName, const Type &value)
	Add result from named object. More...

template<class Type >
Type	getResult (const word &entryName, const Type &defaultValue=Type(Zero)) const
	Retrieve result. More...

template<class Type >
Type	getObjectResult (const word &objectName, const word &entryName, const Type &defaultValue=Type(Zero)) const
	Retrieve result from named object. More...

template<class Type >
bool	getObjectResult (const word &objectName, const word &entryName, Type &value) const
	Set result from named object, return true if set. More...

word	resultType (const word &entryName) const
	Retrieve the result type. More...

word	objectResultType (const word &objectName, const word &entryName) const
	Return the type of result. More...

wordList	objectResultEntries () const
	Retrieve the result entries. More...

wordList	objectResultEntries (const word &objectName) const
	Return result entries for named object. More...

void	writeResultEntries (Ostream &os) const
	Write the results entries for all objects to stream. More...

void	writeResultEntries (const word &objectName, Ostream &os) const
	Write the results entries for named object to stream. More...

void	writeAllResultEntries (Ostream &os) const
	Write the results entries for all objects to stream. More...

Public Member Functions inherited from timeFunctionObject
	timeFunctionObject (const word &name, const Time &runTime)
	Construct from Time. More...

virtual	~timeFunctionObject ()=default
	Destructor. More...

const Time &	time () const
	Return time database. More...

objectRegistry &	storedObjects ()

const objectRegistry &	storedObjects () const

Public Member Functions inherited from functionObject
	declareRunTimeSelectionTable (autoPtr, functionObject, dictionary,(const word &name, const Time &runTime, const dictionary &dict),(name, runTime, dict))

	functionObject (const word &name, const bool withNamePrefix=defaultUseNamePrefix)
	Construct from components. More...

autoPtr< functionObject >	clone () const
	Return clone. More...

virtual	~functionObject ()=default
	Destructor. More...

virtual const word &	type () const =0
	Runtime type information. More...

const word &	name () const noexcept
	Return the name of this functionObject. More...

bool	useNamePrefix () const noexcept
	Return the flag for adding a scoping name prefix. More...

bool	useNamePrefix (bool on) noexcept
	Modify the flag for adding a scoping name prefix. More...

virtual bool	read (const dictionary &dict)
	Read and set the function object if its data have changed. More...

virtual bool	execute ()=0
	Called at each ++ or += of the time-loop. More...

virtual bool	execute (const label subIndex)
	Execute using the specified subIndex. More...

virtual bool	write ()=0
	Called at each ++ or += of the time-loop. More...

virtual bool	end ()
	Called when Time::run() determines that the time-loop exits. More...

virtual bool	adjustTimeStep ()
	Called at the end of Time::adjustDeltaT() if adjustTime is true. More...

virtual bool	filesModified () const
	Did any file get changed during execution? More...

virtual void	updateMesh (const mapPolyMesh &mpm)
	Update for changes of mesh. More...

virtual void	movePoints (const polyMesh &mesh)
	Update for changes of mesh. More...

Additional Inherited Members
Static Public Member Functions inherited from functionObject
static autoPtr< functionObject >	New (const word &name, const Time &runTime, const dictionary &dict)
	Select from dictionary, based on its "type" entry. More...

Public Attributes inherited from functionObject
bool	log
	Flag to write log into Info. More...

Static Public Attributes inherited from functionObject
static int	debug
	Flag to execute debug content. More...

static bool	postProcess
	Global post-processing mode switch. More...

static bool	defaultUseNamePrefix
	Global default for useNamePrefix. More...

static word	outputPrefix
	Directory prefix. More...

Protected Member Functions inherited from fvMeshFunctionObject
	fvMeshFunctionObject (const fvMeshFunctionObject &)=delete
	No copy construct. More...

void	operator= (const fvMeshFunctionObject &)=delete
	No copy assignment. More...

Protected Member Functions inherited from regionFunctionObject
virtual const objectRegistry &	obr () const
	The region or sub-region registry being used. More...

template<class ObjectType >
bool	foundObject (const word &fieldName) const
	Find object (eg, a field) in the (sub) objectRegistry. More...

template<class ObjectType >
const ObjectType *	cfindObject (const word &fieldName) const

template<class ObjectType >
const ObjectType *	findObject (const word &fieldName) const

template<class ObjectType >
ObjectType *	findObject (const word &fieldName)

template<class ObjectType >
ObjectType *	getObjectPtr (const word &fieldName) const

template<class ObjectType >
const ObjectType &	lookupObject (const word &fieldName) const
	Lookup and return object (eg, a field) from the (sub) objectRegistry. More...

template<class ObjectType >
ObjectType &	lookupObjectRef (const word &fieldName) const
	Lookup and return object (eg, a field) from the (sub) objectRegistry. More...

template<class ObjectType >
bool	store (word &fieldName, const tmp< ObjectType > &tfield, bool cacheable=false)
	Store the field in the (sub) objectRegistry under the given name. More...

template<class ObjectType >
bool	storeInDb (const word &fieldName, const tmp< ObjectType > &tfield, const objectRegistry &obr)
	Store the field in an optional objectRegistry under the given name. More...

bool	writeObject (const word &fieldName)
	Write field if present in the (sub) objectRegistry. More...

bool	clearObject (const word &fieldName)
	Clear field from the (sub) objectRegistry if present. More...

void	clearObjects (const wordList &objNames)
	Clear fields from the (sub) objectRegistry if present. More...

	regionFunctionObject (const regionFunctionObject &)=delete
	No copy construct. More...

void	operator= (const regionFunctionObject &)=delete
	No copy assignment. More...

Protected Member Functions inherited from stateFunctionObject
const functionObjects::properties &	stateDict () const
	Return a const reference to the state dictionary. More...

functionObjects::properties &	stateDict ()
	Return non-const access to the state dictionary. More...

	stateFunctionObject (const stateFunctionObject &)=delete
	No copy construct. More...

void	operator= (const stateFunctionObject &)=delete
	No copy assignment. More...

Protected Member Functions inherited from timeFunctionObject
void	clearOutputObjects (const wordList &objNames)
	Remove specified items from "functionObjectObjects". More...

	timeFunctionObject (const timeFunctionObject &)=delete
	No copy construct. More...

void	operator= (const timeFunctionObject &)=delete
	No copy assignment. More...

Protected Member Functions inherited from functionObject
word	scopedName (const word &name) const
	Return a scoped (prefixed) name. More...

Protected Attributes inherited from fvMeshFunctionObject
const fvMesh &	mesh_
	Reference to the fvMesh. More...

Protected Attributes inherited from regionFunctionObject
word	subRegistryName_
	Name for alternative object registry. More...

const objectRegistry &	obr_
	Reference to the region objectRegistry. More...

const objectRegistry *	obrPtr_
	Pointer to alternative (eg, sub-region) objectRegistry. More...

Protected Attributes inherited from timeFunctionObject
const Time &	time_
	Reference to the time database. More...

Detailed Description

Computes a dynamic mode decomposition model on a specified field.

Dynamic mode decomposition (i.e. DMD) is a data-driven dimensionality reduction method. DMD is being used as a mathematical processing tool to reveal dominant modes out of a given field (or dataset) each of which is associated with a constant frequency and decay rate, so that dynamic features of a given flow may become interpretable, tractable, and even reproducible without computing simulations. DMD only relies on input data, therefore it is an equation-free approach.

References:

    DMD characteristics:
        Brunton S. L. (2018).
        Dynamic mode decomposition overview.
        Seattle, Washington: University of Washington.
        youtu.be/sQvrK8AGCAo (Retrieved:24-04-20)

Operands:

Operand Type Location

input

{vol,surface}<Type>Field(s)

<time>/<inputField>(s)

output file dat postProcessing/<FO>/<time>/<file>(s)

output field volVectorField(s) <time>/<outputField>(s)

where <Type>=Scalar/Vector/SphericalTensor/SymmTensor/Tensor.

Output fields:

      modeRe_<modeIndex>_<field>_<FO> | Real part of a mode field
      modeIm_<modeIndex>_<field>_<FO> | Imaginary part of a mode field

Output files:

      dynamics_<field>.dat            | Dynamics data for each mode
      filtered_dynamics_<field>.dat   | Filtered dynamics data for each mode

wherein for each mode, the following quantities are output into files:

\( freq \)	=	Frequency
\( mag \)	=	Magnitude
\( ampRe \)	=	Amplitude coefficients (real part)
\( ampIm \)	=	Amplitude coefficients (imaginary part)
\( evalRe \)	=	Eigenvalue (real part)
\( evalIm \)	=	Eigenvalue (imaginary part)

Usage

Minimal example by using system/controlDict.functions:

DMD1
{
    // Mandatory entries
    type                DMD;
    libs                (fieldFunctionObjects);
    DMDModel            <DMDModel>;
    field               <word>;

    // Optional entries

        // Option-1
        patch               <word>;

        // Option-2
        patches             (<wordRes>);

    // Inherited entries
    ...
}

where the entries mean:

Property	Description	Type	Reqd	Deflt
`type`	Type name: DMD	word	yes	-
`libs`	Library name: fieldFunctionObjects	word	yes	-
`DMDModel`	Name of specified DMD model	word	yes	-
`field`	Name of operand field	word	yes	-
`patch`	Name of operand patch	word	no	null
`patches`	Names of operand patches	wordRes	no	null

Options for the DMDModel entry:

      STDMD    | Streaming total dynamic mode decomposition

The inherited entries are elaborated in:

Minimal example by using the postProcess utility:

        <solver> -postProcess -fields '(U p)' -time '10:'

Note

Warning: DMD is an active research area at the time of writing; therefore, there could be cases whereat oddities can be seen.

See also

Source files

Definition at line 254 of file DMD.H.

Constructor & Destructor Documentation

◆ DMD() [1/2]

DMD	(	const word &	name,
		const Time &	runTime,
		const dictionary &	dict
	)

Construct from Time and dictionary.

Definition at line 133 of file DMD.C.

References dict, Foam::endl(), Foam::exit(), Foam::FatalError, FatalErrorInFunction, Time::isAdjustTimeStep(), fvMeshFunctionObject::mesh_, DMD::read(), runTime, polyMesh::topoChanging(), and WarningInFunction.

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◆ DMD() [2/2]

DMD ( const DMD & )

delete

No copy construct.

◆ ~DMD()

virtual ~DMD ( )

virtualdefault

Destructor.

Member Function Documentation

◆ TypeName()

TypeName ( "DMD" )

Runtime type information.

◆ operator=()

void operator= ( const DMD & )

delete

No copy assignment.

◆ read()

bool read ( const dictionary & dict )

virtual

Read DMD settings.

Reimplemented from regionFunctionObject.

Definition at line 177 of file DMD.C.

References dict, Foam::endl(), Foam::Info, Foam::name(), kEpsilonLopesdaCosta< BasicTurbulenceModel >::read(), and Foam::type().

Referenced by DMD::DMD().

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◆ execute()

bool execute ( )

virtual

Execute DMD.

Implements functionObject.

Definition at line 190 of file DMD.C.

References Foam::endl(), Log, Foam::name(), Foam::tab, and Foam::type().

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◆ write()

bool write ( )

virtual

Write DMD results.

Implements functionObject.

Definition at line 215 of file DMD.C.

◆ end()

bool end ( )

virtual

Write DMD results.

Reimplemented from functionObject.

Definition at line 226 of file DMD.C.

References Foam::endl(), Foam::Info, Log, Foam::name(), Foam::nl, Foam::type(), and WarningInFunction.

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

src/functionObjects/field/DMD/DMD.H
src/functionObjects/field/DMD/DMD.C
src/functionObjects/field/DMD/DMDTemplates.C

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ DMD() [1/2]

◆ DMD() [2/2]

◆ ~DMD()

Member Function Documentation

◆ TypeName()

◆ operator=()

◆ read()

◆ execute()

◆ write()

◆ end()