Dune::GmshReader< GridType > Class Template Reference

Read Gmsh mesh file. More...

#include <dune/grid/io/file/gmshreader.hh>

Public Member Functions
	GmshReader ()=default
	Dynamic Gmsh reader interface.
	GmshReader (const std::string &fileName, Gmsh::ReaderOptions options=defaultOpts)
	Construct a Gmsh reader object (alternatively use one of the static member functions) More...
	GmshReader (const std::string &fileName, GridFactory< Grid > &factory, Gmsh::ReaderOptions options=defaultOpts)
	Construct a Gmsh reader object from a file name and a grid factory. More...
const std::vector< int > &	elementData () const
	Access element data (maps element index to Gmsh physical entity)
const std::vector< int > &	boundaryData () const
	Access boundary data (maps boundary segment index to Gmsh physical entity)
bool	hasElementData () const
	If element data is available. More...
bool	hasBoundaryData () const
	If boundary data is available. More...
std::vector< int >	extractElementData ()
	Erase element data from reader and return the data.
std::vector< int >	extractBoundaryData ()
	Erase boundary data from reader and return the data.
std::unique_ptr< Grid >	createGrid ()
	Create the grid.

Static Public Member Functions
static std::unique_ptr< Grid >	read (const std::string &fileName, bool verbose=true, bool insertBoundarySegments=true)
static std::unique_ptr< Grid >	read (const std::string &fileName, std::vector< int > &boundarySegmentToPhysicalEntity, std::vector< int > &elementToPhysicalEntity, bool verbose=true, bool insertBoundarySegments=true)
	Read Gmsh file, possibly with data. More...
static void	read (Dune::GridFactory< Grid > &factory, const std::string &fileName, bool verbose=true, bool insertBoundarySegments=true)
static void	read (Dune::GridFactory< Grid > &factory, const std::string &fileName, DataFlagArg boundarySegmentData, DataArg elementData, bool verbose=true)
	read Gmsh file, possibly with data More...
static void	read (Dune::GridFactory< Grid > &factory, const std::string &fileName, std::vector< int > &boundarySegmentToPhysicalEntity, std::vector< int > &elementToPhysicalEntity, bool verbose, bool insertBoundarySegments)
	Read Gmsh file, possibly with data. More...

Detailed Description

template<typename GridType>
class Dune::GmshReader< GridType >

Read Gmsh mesh file.

Read a .msh (version 2) file generated using Gmsh and construct a grid using the grid factory interface.

The file format used by gmsh can hold grids that are more general than the simplex grids that the gmsh grid generator is able to construct. We try to read as many grids as possible, as long as they are valid files. You can test this by checking whether gmsh will load the file and display its content.

All grids in a gmsh file live in three-dimensional Euclidean space. If the world dimension of the grid type that you are reading the file into is less than three, the remaining coordinates are simply ignored.

Note

Recent versions of Gmsh introduced a new .msh file format (version 4) with a different syntax. This is currently not supported by GmshReader. One can export to an older .msh version as follows:

• select File→Export (or CTRL+E)
• select file format .msh
• a dialog asks for options
• select 'Version 2 ASCII' and mark 'Save all elements'

Constructor & Destructor Documentation

GmshReader() [1/2]

template<typename GridType >

Dune::GmshReader< GridType >::GmshReader ( const std::string &  fileName, Gmsh::ReaderOptions  options = defaultOpts  )

inline

Construct a Gmsh reader object (alternatively use one of the static member functions)

Construct a Gmsh reader object from a file name

Parameters

fileName	Name of the file to read from.
options	Options of the type Dune::Gmsh::ReaderOptions

To pass several options, combine them with the |-operator like this

using Opt = Dune::Gmsh::ReaderOptions;
auto reader = Dune::GmshReader("grid.msh", Opt::verbose | Opt::readElementData)

Per default the reader has enabled the following options

• Dune::Gmsh::ReaderOptions::verbose
• Dune::Gmsh::ReaderOptions::insertBoundarySegments
• Dune::Gmsh::ReaderOptions::readBoundaryData
• Dune::Gmsh::ReaderOptions::readElementData

Passing any option to the interface will overwrite these defaults.

A Dune grid object can be obtained via the createGrid() member

GmshReader() [2/2]

template<typename GridType >

Dune::GmshReader< GridType >::GmshReader ( const std::string &  fileName, GridFactory< Grid > &  factory, Gmsh::ReaderOptions  options = defaultOpts  )

inline

Construct a Gmsh reader object from a file name and a grid factory.

Parameters

fileName	Name of the file to read from.
options	Options of the type Dune::Gmsh::ReaderOptions

Note

Use this constructor if you need access to the grid factor, e.g. for obtaining boundary segment insertion indices.

Member Function Documentation

hasBoundaryData()

template<typename GridType >

bool Dune::GmshReader< GridType >::hasBoundaryData ( ) const

inline

If boundary data is available.

Note

This is false if no such data was requested

hasElementData()

template<typename GridType >

bool Dune::GmshReader< GridType >::hasElementData ( ) const

inline

If element data is available.

Note

This is false if no such data was requested

read() [1/5]

template<typename GridType >

static std::unique_ptr<Grid> Dune::GmshReader< GridType >::read ( const std::string &  fileName, bool  verbose = true, bool  insertBoundarySegments = true  )

inlinestatic

Todo:

doc me

Returns

The return type is a special pointer type that casts into Grid*, std::unique_ptr<Grid>, and std::shared_ptr<Grid>. It is scheduled to be replaced by std::unique_ptr<Grid> eventually.

References Dune::GridFactory< GridType >::createGrid().

read() [2/5]

template<typename GridType >

static std::unique_ptr<Grid> Dune::GmshReader< GridType >::read ( const std::string &  fileName, std::vector< int > &  boundarySegmentToPhysicalEntity, std::vector< int > &  elementToPhysicalEntity, bool  verbose = true, bool  insertBoundarySegments = true  )

inlinestatic

Read Gmsh file, possibly with data.

Parameters

fileName	Name of the file to read from.
boundarySegmentToPhysicalEntity	Container to fill with boundary segment physical entity data (if insertBoundarySegments=true)
elementToPhysicalEntity	Container to fill with element physical entity data
verbose	Whether to be chatty
insertBoundarySegments	Whether boundary segments are inserted into the factory

Note

When insertBoundarySegments=false there is no way to correctly use the values returned in boundarySegmentToPhysicalEntity. Make sure to set insertBoundarySegments=true if you intent to do this. An alternative is to use the other overloads which provide compile-time checking of the provided parameter combinations.

Todo:

This interface is error-prone and should not be exposed to the user. However, the compile-time overloads may not provide sufficient runtime flexibility in all cases. Therefore this interface is kept until a better interface can be agreed on. See https://gitlab.dune-project.org/core/dune-grid/-/issues/107

References Dune::GridFactory< GridType >::createGrid().

read() [3/5]

template<typename GridType >

static void Dune::GmshReader< GridType >::read ( Dune::GridFactory< Grid > &  factory, const std::string &  fileName, bool  verbose = true, bool  insertBoundarySegments = true  )

inlinestatic

Todo:

doc me

read() [4/5]

template<typename GridType >

static void Dune::GmshReader< GridType >::read ( Dune::GridFactory< Grid > &  factory, const std::string &  fileName, DataFlagArg  boundarySegmentData, DataArg  elementData, bool  verbose = true  )

inlinestatic

read Gmsh file, possibly with data

Parameters

factory	The GridFactory to fill.
fileName	Name of the file to read from.
boundarySegmentData	Container to fill with boundary segment physical entity data, or std::ignore, or a bool value. Boundary segments are inserted when a container or true is given, otherwise they are not inserted.
elementData	Container to fill with element physical entity data, or std::ignore.
verbose	Whether to be chatty.

Containers to fill with data must be std::vector<int> lvalues. Element data is indexed by the insertion index of the element, boundarySegment data is indexed by the insertion index of the boundary intersection. These can be obtained from the factory, and are lost once the grid gets modified (refined or load-balanced).

Note

At the moment the data containers are still filled internally, even if they are ignored. So not having to pass them is more of a convenience feature and less of an optimization. This may however change in the future.

References Dune::GmshReader< GridType >::elementData().

read() [5/5]

template<typename GridType >

static void Dune::GmshReader< GridType >::read ( Dune::GridFactory< Grid > &  factory, const std::string &  fileName, std::vector< int > &  boundarySegmentToPhysicalEntity, std::vector< int > &  elementToPhysicalEntity, bool  verbose, bool  insertBoundarySegments  )

inlinestatic

Read Gmsh file, possibly with data.

Parameters

factory	The GridFactory to fill.
fileName	Name of the file to read from.
boundarySegmentToPhysicalEntity	Container to fill with boundary segment physical entity data (if insertBoundarySegments=true)
elementToPhysicalEntity	Container to fill with element physical entity data
verbose	Whether to be chatty
insertBoundarySegments	Whether boundary segments are inserted into the factory

Note

When insertBoundarySegments=false there is no way to correctly use the values returned in boundarySegmentToPhysicalEntity. Make sure to set insertBoundarySegments=true if you intent to do this. An alternative is to use the other overloads which provide compile-time checking of the provided parameter combinations.

Todo:

This interface is error-prone and should not be exposed to the user. However, the compile-time overloads may not provide sufficient runtime flexibility in all cases. Therefore this interface is kept until a better interface can be agreed on. See https://gitlab.dune-project.org/core/dune-grid/-/issues/107

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

• dune/grid/io/file/gmshreader.hh