Regina 7.3 Calculation Engine
Public Member Functions | Public Attributes | List of all members
regina::GluingPermSearcher< 4 >::PentTriangleState Struct Reference

A structure used to track equivalence classes of pentachoron triangles as the gluing permutation set is constructed. More...

#include <census/gluingpermsearcher4.h>

Public Member Functions

 PentTriangleState ()
 Constructor for a standalone pentachoron triangle in an equivalence class all of its own. More...
 
void dumpData (std::ostream &out) const
 Dumps all internal data in a plain text format to the given output stream. More...
 
bool readData (std::istream &in, size_t nStates)
 Fills this state with data read from the given input stream. More...
 
 PentTriangleState (const PentTriangleState &)=delete
 
PentTriangleStateoperator= (const PentTriangleState &)=delete
 

Public Attributes

ssize_t parent
 The index of the parent object in the current tree, or -1 if this object is the root of the tree. More...
 
size_t rank
 The depth of the subtree beneath this object (where a leaf node has depth zero). More...
 
size_t size
 The total number of objects in the subtree descending from this object (where this object is counted also). More...
 
bool bounded
 Does this equivalence class of pentachoron triangles represent a boundary triangle? More...
 
Perm< 3 > twistUp
 The vertices of each pentachoron triangle can be labelled (0,1,2) by running through the underlying pentachoron vertices from smallest index to largest index. More...
 
bool hadEqualRank
 Did this tree have rank equal to its parent immediately before it was grafted beneath its parent? This information is used to maintain the ranks correctly when grafting operations are undone. More...
 

Detailed Description

A structure used to track equivalence classes of pentachoron triangles as the gluing permutation set is constructed.

Two triangles are considered equivalent if they are identified within the 4-manifold triangulation.

Pentachoron triangles are indexed linearly by pentachoron and then triangle number. Specifically, triangle f (0..9) of pentachoron p (0..nPents-1) has index 10p+f.

Each equivalence class of triangles corresponds to a tree of PentTriangleState objects, arranged to form a modified union-find structure.

Constructor & Destructor Documentation

◆ PentTriangleState()

regina::GluingPermSearcher< 4 >::PentTriangleState::PentTriangleState ( )
inline

Constructor for a standalone pentachoron triangle in an equivalence class all of its own.

Member Function Documentation

◆ dumpData()

void regina::GluingPermSearcher< 4 >::PentTriangleState::dumpData ( std::ostream &  out) const

Dumps all internal data in a plain text format to the given output stream.

This state can be recreated from this text data by calling readData().

This routine may be useful for transferring objects from one processor to another.

Warning
The data format is liable to change between Regina releases. Data in this format should be used on a short-term temporary basis only.
Parameters
outthe output stream to which the data should be written.

◆ readData()

bool regina::GluingPermSearcher< 4 >::PentTriangleState::readData ( std::istream &  in,
size_t  nStates 
)

Fills this state with data read from the given input stream.

This routine reads data in the format written by dumpData().

Warning
The data format is liable to change between Regina releases. Data in this format should be used on a short-term temporary basis only.

This routine does test for bad input data, but it does not test for end-of-file.

Parameters
inthe input stream from which to read.
nStatesthe total number of triangle states under consideration (this must be ten times the number of pentachora).
Returns
false if any errors were encountered during reading, or true otherwise.

Member Data Documentation

◆ bounded

bool regina::GluingPermSearcher< 4 >::PentTriangleState::bounded

Does this equivalence class of pentachoron triangles represent a boundary triangle?

If this equivalence class describes a complete loop of pentachoron triangles then the value of bounded is false. If this equivalence class describes a string of pentachoron triangles with two endpoints, the value of bounded is true. Here we treat any facet whose gluing permutation has not yet been decided as a boundary facet.

This value is only maintained correctly for the root of the corresponding object tree; other objects in the tree will have older values to facilitate backtracking.

◆ hadEqualRank

bool regina::GluingPermSearcher< 4 >::PentTriangleState::hadEqualRank

Did this tree have rank equal to its parent immediately before it was grafted beneath its parent? This information is used to maintain the ranks correctly when grafting operations are undone.

If this object is still the root of its tree, this value is set to false.

◆ parent

ssize_t regina::GluingPermSearcher< 4 >::PentTriangleState::parent

The index of the parent object in the current tree, or -1 if this object is the root of the tree.

◆ rank

size_t regina::GluingPermSearcher< 4 >::PentTriangleState::rank

The depth of the subtree beneath this object (where a leaf node has depth zero).

◆ size

size_t regina::GluingPermSearcher< 4 >::PentTriangleState::size

The total number of objects in the subtree descending from this object (where this object is counted also).

◆ twistUp

Perm<3> regina::GluingPermSearcher< 4 >::PentTriangleState::twistUp

The vertices of each pentachoron triangle can be labelled (0,1,2) by running through the underlying pentachoron vertices from smallest index to largest index.

The parameter twistUp is a permutation that maps vertices (0,1,2) of this triangle to vertices (0,1,2) of its parent in the tree according to the way in which the two triangles are identified. If this object has no parent, the value of twistUp is undefined.


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

Copyright © 1999-2023, The Regina development team
This software is released under the GNU General Public License, with some additional permissions; see the source code for details.
For further information, or to submit a bug or other problem, please contact Ben Burton (bab@maths.uq.edu.au).