Represents a snapped 3-ball in a triangulation. More...

#include <subcomplex/snappedball.h>

Inheritance diagram for regina::SnappedBall:

Public Member Functions
	SnappedBall (const SnappedBall &)=default
	Creates a new copy of the given structure. More...

SnappedBall &	operator= (const SnappedBall &)=default
	Sets this to be a copy of the given structure. More...

void	swap (SnappedBall &other) noexcept
	Swaps the contents of this and the given structure. More...

Tetrahedron< 3 > *	tetrahedron () const
	Returns the tetrahedron that forms this snapped ball. More...

int	boundaryFace (int index) const
	Returns one of the two tetrahedron faces that forms the boundary of this snapped ball. More...

int	internalFace (int index) const
	Returns one of the two tetrahedron faces internal to this snapped ball. More...

int	equatorEdge () const
	Returns the edge that forms the equator of the boundary sphere of this ball. More...

int	internalEdge () const
	Returns the edge internal to this snapped ball. More...

bool	operator== (const SnappedBall &other) const
	Determines whether this and the given object represent the same specific presentation of a snapped 3-ball. More...

bool	operator!= (const SnappedBall &other) const
	Determines whether this and the given object represent different specific presentations of a snapped 3-ball. More...

std::unique_ptr< Manifold >	manifold () const override
	Returns the 3-manifold represented by this triangulation, if such a recognition routine has been implemented. More...

AbelianGroup	homology () const override
	Returns the expected first homology group of this triangulation, if such a routine has been implemented. More...

std::ostream &	writeName (std::ostream &out) const override
	Writes the name of this triangulation as a human-readable string to the given output stream. More...

std::ostream &	writeTeXName (std::ostream &out) const override
	Writes the name of this triangulation in TeX format to the given output stream. More...

void	writeTextShort (std::ostream &out) const override
	Writes a short text representation of this object to the given output stream. More...

std::string	name () const
	Returns the name of this specific triangulation as a human-readable string. More...

std::string	texName () const
	Returns the name of this specific triangulation in TeX format. More...

virtual void	writeTextLong (std::ostream &out) const
	Writes a detailed text representation of this object to the given output stream. More...

std::string	str () const
	Returns a short text representation of this object. More...

std::string	utf8 () const
	Returns a short text representation of this object using unicode characters. More...

std::string	detail () const
	Returns a detailed text representation of this object. More...

Static Public Member Functions
static std::unique_ptr< SnappedBall >	recognise (Tetrahedron< 3 > *tet)
	Determines if the given tetrahedron forms a snapped 3-ball within a triangulation. More...

static std::unique_ptr< StandardTriangulation >	recognise (Component< 3 > *component)
	Determines whether the given component represents one of the standard triangulations understood by Regina. More...

static std::unique_ptr< StandardTriangulation >	recognise (const Triangulation< 3 > &tri)
	Determines whether the given triangulation represents one of the standard triangulations understood by Regina. More...

Detailed Description

Represents a snapped 3-ball in a triangulation.

A snapped 3-ball is a single tetrahedron with two faces glued to each other to form a 3-ball with a two triangle boundary.

All optional StandardTriangulation routines are implemented for this class.

This class supports copying but does not implement separate move operations, since its internal data is so small that copying is just as efficient. It implements the C++ Swappable requirement via its own member and global swap() functions, for consistency with the other StandardTriangulation subclasses. Note that the only way to create these objects (aside from copying or moving) is via the static member function recognise().

Constructor & Destructor Documentation

◆ SnappedBall()

regina::SnappedBall::SnappedBall ( const SnappedBall & )

default

Creates a new copy of the given structure.

Member Function Documentation

◆ boundaryFace()

int regina::SnappedBall::boundaryFace ( int index ) const

inline

Returns one of the two tetrahedron faces that forms the boundary of this snapped ball.

You are guaranteed that index 0 will return a smaller face number than index 1.

Parameters

index specifies which of the two boundary faces to return; this must be either 0 or 1.

Returns: the corresponding face number in the tetrahedron.

◆ detail()

std::string regina::Output< StandardTriangulation , false >::detail ( ) const

inherited

Returns a detailed text representation of this object.

This text may span many lines, and should provide the user with all the information they could want. It should be human-readable, should not contain extremely long lines (which cause problems for users reading the output in a terminal), and should end with a final newline. There are no restrictions on the underlying character set.

Returns: a detailed text representation of this object.

◆ equatorEdge()

int regina::SnappedBall::equatorEdge ( ) const

inline

Returns the edge that forms the equator of the boundary sphere of this ball.

Returns: the corresponding edge number in the tetrahedron.

◆ homology()

AbelianGroup regina::SnappedBall::homology ( ) const

overridevirtual

Returns the expected first homology group of this triangulation, if such a routine has been implemented.

This routine does not work by calling Triangulation<3>::homology() on the associated real triangulation. Instead the homology is calculated directly from the known properties of this standard triangulation.

This means that homology() needs to be implemented separately for each class of standard triangulation. See the class notes for each subclass of StandardTriangulation for details on whether homology has been implemented for that particular subclass. The default implementation of this routine just throws a NotImplemented exception.

Most users will not need this routine, since presumably you already have an explicit Triangulation<3> available and so you can just call Triangulation<3>::homology() instead (which, unlike this routine, is always implemented). This StandardTriangulation::homology() routine should be seen as more of a verification/validation tool for the Regina developers.

If this StandardTriangulation describes an entire Triangulation<3> (and not just a part thereof) then the results of this routine should be identical to the homology group obtained by calling Triangulation<3>::homology() upon the associated real triangulation.

Exceptions

NotImplemented	Homology calculation has not yet been implemented for this particular type of standard triangulation.
FileError	The homology needs to be read from file (as opposed to computed), but the file is inaccessible or its contents cannot be read and parsed correctly. Currently this can only happen for the subclass SnapPeaCensusTri, which reads its results from the SnapPea census databases that are installed with Regina.

Returns: the first homology group of this triangulation, if this functionality has been implemented.

Reimplemented from regina::StandardTriangulation.

◆ internalEdge()

int regina::SnappedBall::internalEdge ( ) const

inline

Returns the edge internal to this snapped ball.

Returns: the corresponding edge number in the tetrahedron.

◆ internalFace()

int regina::SnappedBall::internalFace ( int index ) const

inline

Returns one of the two tetrahedron faces internal to this snapped ball.

You are guaranteed that index 0 will return a smaller face number than index 1.

Parameters

index specifies which of the two internal faces to return; this must be either 0 or 1.

Returns: the corresponding face number in the tetrahedron.

◆ manifold()

std::unique_ptr< Manifold > regina::SnappedBall::manifold ( ) const

overridevirtual

Returns the 3-manifold represented by this triangulation, if such a recognition routine has been implemented.

If the 3-manifold cannot be recognised then this routine will return null.

The details of which standard triangulations have 3-manifold recognition routines can be found in the notes for the corresponding subclasses of StandardTriangulation. The default implementation of this routine returns null.

It is expected that the number of triangulations whose underlying 3-manifolds can be recognised will grow between releases.

Returns: the underlying 3-manifold.

Reimplemented from regina::StandardTriangulation.

◆ name()

std::string regina::StandardTriangulation::name ( ) const

inherited

Returns the name of this specific triangulation as a human-readable string.

Returns: the name of this triangulation.

◆ operator!=()

bool regina::SnappedBall::operator!= ( const SnappedBall & other ) const

inline

Determines whether this and the given object represent different specific presentations of a snapped 3-ball.

Unlike the parameterised subclasses of StandardTriangulation, this SnappedBall subclass represents a fixed structure, and so its comparisons test not for the structure but the precise location of this structure within the enclosing triangulation.

Specifically, two snapped 3-balls will compare as equal if and only if each uses the same numbered tetrahedron, and has the same numbered equator edge within that tetrahedron. That is, the tetrahedra returned by tetrahedron() must have equal indices within the triangulation, and the edge numbers returned by equatorEdge() must be equal. In particular, it is still meaningful to compare snapped 3-balls within different triangulations.

Parameters

other the snapped 3-ball to compare with this.

Returns: true if and only if this and the given object represent different specific presentations of a snapped 3-ball.

◆ operator=()

SnappedBall & regina::SnappedBall::operator= ( const SnappedBall & )

default

Sets this to be a copy of the given structure.

Returns: a reference to this structure.

◆ operator==()

bool regina::SnappedBall::operator== ( const SnappedBall & other ) const

inline

Determines whether this and the given object represent the same specific presentation of a snapped 3-ball.

Unlike the parameterised subclasses of StandardTriangulation, this SnappedBall subclass represents a fixed structure, and so its comparisons test not for the structure but the precise location of this structure within the enclosing triangulation.

Specifically, two snapped 3-balls will compare as equal if and only if each uses the same numbered tetrahedron, and has the same numbered equator edge within that tetrahedron. That is, the tetrahedra returned by tetrahedron() must have equal indices within the triangulation, and the edge numbers returned by equatorEdge() must be equal. In particular, it is still meaningful to compare snapped 3-balls within different triangulations.

Parameters

other the snapped 3-ball to compare with this.

Returns: true if and only if this and the given object represent the same specific presentation of a snapped 3-ball.

◆ recognise() [1/3]

static std::unique_ptr< StandardTriangulation > regina::StandardTriangulation::recognise ( Component< 3 > * component )

staticinherited

Determines whether the given component represents one of the standard triangulations understood by Regina.

The list of recognised triangulations is expected to grow between releases.

If the standard triangulation returned has boundary triangles then the given component must have the same corresponding boundary triangles, i.e., the component cannot have any further identifications of these boundary triangles with each other.

Note that the triangulation-based routine recognise(const Triangulation<3>&) may recognise more triangulations than this routine, since passing an entire triangulation allows access to more information.

Parameters

component the triangulation component under examination.

Returns: the details of the standard triangulation if the given component is recognised, or null otherwise.

◆ recognise() [2/3]

static std::unique_ptr< StandardTriangulation > regina::StandardTriangulation::recognise ( const Triangulation< 3 > & tri )

staticinherited

Determines whether the given triangulation represents one of the standard triangulations understood by Regina.

The list of recognised triangulations is expected to grow between releases.

If the standard triangulation returned has boundary triangles then the given triangulation must have the same corresponding boundary triangles, i.e., the triangulation cannot have any further identifications of these boundary triangles with each other.

This routine may recognise more triangulations than the component-based recognise(Component<3>*), since passing an entire triangulation allows access to more information.

Parameters

tri	the triangulation under examination.

Returns: the details of the standard triangualation if the given triangulation is recognised, or null otherwise.

◆ recognise() [3/3]

static std::unique_ptr< SnappedBall > regina::SnappedBall::recognise ( Tetrahedron< 3 > * tet )

static

Determines if the given tetrahedron forms a snapped 3-ball within a triangulation.

The ball need not be the entire triangulation; the boundary triangles may be glued to something else (or to each other).

Note that the two boundary triangles of the snapped 3-ball need not be boundary triangles within the overall triangulation, i.e., they may be identified with each other or with triangles of other tetrahedra.

This function returns by (smart) pointer for consistency with StandardTriangulation::recognise(), which makes use of the polymorphic nature of the StandardTriangulation class hierarchy.

Parameters

tet	the tetrahedron to examine as a potential 3-ball.

Returns: a structure containing details of the snapped 3-ball, or null if the given tetrahedron is not a snapped 3-ball.

◆ str()

std::string regina::Output< StandardTriangulation , false >::str ( ) const

inherited

Returns a short text representation of this object.

This text should be human-readable, should use plain ASCII characters where possible, and should not contain any newlines.

Within these limits, this short text ouptut should be as information-rich as possible, since in most cases this forms the basis for the Python __str__() and __repr__() functions.

Python: The Python "stringification" function __str__() will use precisely this function, and for most classes the Python __repr__() function will incorporate this into its output.

Returns: a short text representation of this object.

◆ swap()

void regina::SnappedBall::swap ( SnappedBall & other )

inlinenoexcept

Swaps the contents of this and the given structure.

Parameters

other the structure whose contents should be swapped with this.

◆ tetrahedron()

Tetrahedron< 3 > * regina::SnappedBall::tetrahedron ( ) const

inline

Returns the tetrahedron that forms this snapped ball.

Returns: the tetrahedron.

◆ texName()

std::string regina::StandardTriangulation::texName ( ) const

inherited

Returns the name of this specific triangulation in TeX format.

No leading or trailing dollar signs will be included.

Warning: The behaviour of this routine has changed as of Regina 4.3; in earlier versions, leading and trailing dollar signs were provided.

Returns: the name of this triangulation in TeX format.

◆ utf8()

std::string regina::Output< StandardTriangulation , false >::utf8 ( ) const

inherited

Returns a short text representation of this object using unicode characters.

Like str(), this text should be human-readable, should not contain any newlines, and (within these constraints) should be as information-rich as is reasonable.

Unlike str(), this function may use unicode characters to make the output more pleasant to read. The string that is returned will be encoded in UTF-8.

Returns: a short text representation of this object.

◆ writeName()

std::ostream & regina::SnappedBall::writeName ( std::ostream & out ) const

inlineoverridevirtual

Writes the name of this triangulation as a human-readable string to the given output stream.

Python: Not present. Instead use the variant name() that takes no arguments and returns a string.

Parameters

out	the output stream to which to write.

Returns: a reference to the given output stream.

Implements regina::StandardTriangulation.

◆ writeTeXName()

std::ostream & regina::SnappedBall::writeTeXName ( std::ostream & out ) const

inlineoverridevirtual

Writes the name of this triangulation in TeX format to the given output stream.

No leading or trailing dollar signs will be included.

Warning: The behaviour of this routine has changed as of Regina 4.3; in earlier versions, leading and trailing dollar signs were provided.

Python: Not present. Instead use the variant texName() that takes no arguments and returns a string.

Parameters

out	the output stream to which to write.

Returns: a reference to the given output stream.

Implements regina::StandardTriangulation.

◆ writeTextLong()

void regina::StandardTriangulation::writeTextLong ( std::ostream & out ) const

inlinevirtualinherited

Writes a detailed text representation of this object to the given output stream.

This may be reimplemented by subclasses, but the parent StandardTriangulation class offers a reasonable default implementation based on writeTextShort().

Python: Not present. Use detail() instead.

Parameters

out	the output stream to which to write.

Reimplemented in regina::AugTriSolidTorus, regina::BlockedSFS, regina::BlockedSFSLoop, regina::BlockedSFSPair, regina::BlockedSFSTriple, regina::LayeredChainPair, regina::LayeredLensSpace, regina::LayeredLoop, regina::LayeredTorusBundle, regina::PluggedTorusBundle, regina::PlugTriSolidTorus, and regina::TrivialTri.

◆ writeTextShort()

void regina::SnappedBall::writeTextShort ( std::ostream & out ) const

inlineoverridevirtual

Writes a short text representation of this object to the given output stream.

This may be reimplemented by subclasses, but the parent StandardTriangulation class offers a reasonable default implementation based on writeName().

Python: Not present. Use str() instead.

Parameters

out	the output stream to which to write.

Reimplemented from regina::StandardTriangulation.

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

subcomplex/snappedball.h

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ SnappedBall()

Member Function Documentation

◆ boundaryFace()

◆ detail()

◆ equatorEdge()

◆ homology()

◆ internalEdge()

◆ internalFace()

◆ manifold()

◆ name()

◆ operator!=()

◆ operator=()

◆ operator==()

◆ recognise() [1/3]

◆ recognise() [2/3]

◆ recognise() [3/3]

◆ str()

◆ swap()

◆ tetrahedron()

◆ texName()

◆ utf8()

◆ writeName()

◆ writeTeXName()

◆ writeTextLong()

◆ writeTextShort()