regina::IsoSigClassic< dim > Class Template Reference

The default signature type to use for isomorphism signatures. More...

#include <triangulation/isosigtype.h>

Public Member Functions
	IsoSigClassic (const Component< dim > &comp)
	Initialises this object to iterate through candidate "starting simplices" s and "starting labellings" p for the given triangulation component. More...
size_t	simplex () const
	Returns the current starting simplex s. More...
Perm< dim+1 >	perm () const
	Returns the current starting labelling p of the vertices of the current starting simplex. More...
bool	next ()
	Advances this object to the next candidate pair (s, p). More...
	IsoSigClassic (const IsoSigClassic &)=delete
IsoSigClassic &	operator= (const IsoSigClassic &)=delete

Detailed Description

template<int dim>
class regina::IsoSigClassic< dim >

The default signature type to use for isomorphism signatures.

This signature type is consistent with the original isomorphism signatures that were implemented in Regina 4.90.

A signature type class such as this works with a single component c of a dim-dimenensional triangulation. The sole task of a type class is to iterate through a selection of combinations (s, p), each of which identifies a "starting simplex" and a "starting labelling" of its vertices. Here s is a top-dimensional simplex in c that will act as the "starting simplex", and p is a permutation that maps the vertices of s to the "starting labelling" 0,1,...,dim.

The properties that any signature type must satisfy are:

• The selection of combinations (s, p) is always non-empty.
• If we reorder the top-dimensional simplices of c and/or relabel their individual vertices, then the combinations (s, p) that this type class produces will be the same set, but modified according to this reordering/relabelling. In other words, the starting simplices and their starting labellings can in theory be completely deduced from an unlabelled triangulation component.

An instance of a type class is like an iterator: it holds a single candidate combination (s, p). The constructor must initialise the instance to store the first candidate combination; you can then query the current combination by calling simplex() and perm(), and you can advance to the next combination by calling next().

This classic signature type is trivial, in that it considers all possible simplices s and all (dim+1)! possible permutations p.

This class is designed to be used as a template parameter for Triangulation<dim>::isoSig() and Triangulation<dim>::isoSigDetail(). Typical users would have no need to create objects of this class or call any of its functions directly.

Python

Python does not support templates. Instead this class can be used by appending the dimension as a suffix (e.g., IsoSigClassic2 and IsoSigClassic3 for dimensions 2 and 3).

Constructor & Destructor Documentation

IsoSigClassic()

template<int dim>

regina::IsoSigClassic< dim >::IsoSigClassic ( const Component< dim > &  comp )

inline

Initialises this object to iterate through candidate "starting simplices" s and "starting labellings" p for the given triangulation component.

See the class notes for details.

This object will initially be set to hold the first candidate pair (s, p).

Parameters

comp	the triangulation component that we are examining.

Member Function Documentation

next()

template<int dim>

bool regina::IsoSigClassic< dim >::next

inline

Advances this object to the next candidate pair (s, p).

See the class notes for further details.

Precondition

This object is holding a valid candidate pair (s, p); that is, next() has not yet returned false.

Returns

true if this was successful, or false if there is no next candidate pair (i.e., the current candidate pair is the last).

perm()

template<int dim>

Perm< dim+1 > regina::IsoSigClassic< dim >::perm

inline

Returns the current starting labelling p of the vertices of the current starting simplex.

See the class notes for further details.

Precondition

This object is holding a valid candidate pair (s, p); that is, next() has not yet returned false.

Returns

the starting labelling, given as a permutation that maps the current vertex labels of the starting simplex s to the "canonical" labels 0,1,...,dim.

simplex()

template<int dim>

size_t regina::IsoSigClassic< dim >::simplex

inline

Returns the current starting simplex s.

See the class notes for further details.

Precondition

This object is holding a valid candidate pair (s, p); that is, next() has not yet returned false.

Returns

the index of the current starting simplex with respect to the triangulation component under consideration. Note that, for a disconnected triangulation, this is not necessarily the same as Simplex::index() (which gives the index with respect to the overall triangulation).

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

• triangulation/detail/triangulation.h
• triangulation/isosigtype.h