Regina Calculation Engine

A structure used to track equivalence classes of tetrahedron edges as the gluing permutation set is constructed. More...
#include <census/ngluingpermsearcher.h>
Public Member Functions  
TetEdgeState ()  
Constructor for a standalone tetrahedron edge in an equivalence class all of its own. More...  
void  dumpData (std::ostream &out, unsigned nTets) const 
Dumps all internal data in a plain text format to the given output stream. More...  
bool  readData (std::istream &in, unsigned nTets) 
Fills this state with data read from the given input stream. More...  
Public Attributes  
int  parent 
The index of the parent object in the current tree, or 1 if this object is the root of the tree. More...  
unsigned  rank 
The depth of the subtree beneath this object (where a leaf node has depth zero). More...  
unsigned  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 tetrahedron edges represent a boundary edge? More...  
char  twistUp 
Each tetrahedron edge can be assigned an orientation pointing from the lower numbered tetrahedron vertex to the higher. 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...  
NQitmaskLen64  facesPos 
Indicates how many times this edge runs along the boundary of each tetrahedron face in the positive direction. More...  
NQitmaskLen64  facesNeg 
Indicates how many times this edge runs along the boundary of each tetrahedron face in the negative direction. More...  
A structure used to track equivalence classes of tetrahedron edges as the gluing permutation set is constructed.
Two edges are considered equivalent if they are identified within the triangulation.
Tetrahedron edges are indexed linearly by tetrahedron and then edge number. Specifically, edge e (0..5) of tetrahedron t (0..nTets1) has index 6t+e.
Each equivalence class of edges corresponds to a tree of TetEdgeState objects, arranged to form a modified unionfind structure.

inline 
Constructor for a standalone tetrahedron edge in an equivalence class all of its own.
void regina::NCompactSearcher::TetEdgeState::dumpData  (  std::ostream &  out, 
unsigned  nTets  
)  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.
nTets  the number of tetrahedra under consideration in the census. 
out  the output stream to which the data should be written. 
bool regina::NCompactSearcher::TetEdgeState::readData  (  std::istream &  in, 
unsigned  nTets  
) 
Fills this state with data read from the given input stream.
This routine reads data in the format written by dumpData().
This routine does test for bad input data, but it does not test for endoffile.
in  the input stream from which to read. 
nTets  the number of tetrahedra under consideration in the census. 
false
if any errors were encountered during reading, or true
otherwise. bool regina::NCompactSearcher::TetEdgeState::bounded 
Does this equivalence class of tetrahedron edges represent a boundary edge?
If this equivalence class describes a complete loop of tetrahedron edges then the value of bounded is false
. If this equivalence class describes a string of tetrahedron edges with two endpoints, the value of bounded is true
. Here we treat any face whose gluing permutation has not yet been decided as a boundary face.
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.
NQitmaskLen64 regina::NCompactSearcher::TetEdgeState::facesNeg 
Indicates how many times this edge runs along the boundary of each tetrahedron face in the negative direction.
Specifically, the (4t+i)th trit counts how many times it runs in the negative direction around the boundary of face i of tetrahedron t. Which direction is "negative" is chosen arbitrarily for each face; for details see the implementation of the NCompactSearcher constructor.
Because of the fixedsize data type, this only stores information for the faces of the first 16 tetrahedra.
Currently this data member is initialised by the NCompactSearcher constructors (since it belongs to TetEdgeState), but it is only used and updated in the subclass NClosedPrimeMinSearcher (where it allows us to optimise the census algorithm).
NQitmaskLen64 regina::NCompactSearcher::TetEdgeState::facesPos 
Indicates how many times this edge runs along the boundary of each tetrahedron face in the positive direction.
Specifically, the (4t+i)th trit counts how many times it runs in the positive direction around the boundary of face i of tetrahedron t. Which direction is "positive" is chosen arbitrarily for each face; for details see the implementation of the NCompactSearcher constructor.
Because of the fixedsize data type, this only stores information for the faces of the first 16 tetrahedra.
Currently this data member is initialised by the NCompactSearcher constructors (since it belongs to TetEdgeState), but it is only used and updated in the subclass NClosedPrimeMinSearcher (where it allows us to optimise the census algorithm).
bool regina::NCompactSearcher::TetEdgeState::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.
int regina::NCompactSearcher::TetEdgeState::parent 
The index of the parent object in the current tree, or 1 if this object is the root of the tree.
unsigned regina::NCompactSearcher::TetEdgeState::rank 
The depth of the subtree beneath this object (where a leaf node has depth zero).
unsigned regina::NCompactSearcher::TetEdgeState::size 
The total number of objects in the subtree descending from this object (where this object is counted also).
char regina::NCompactSearcher::TetEdgeState::twistUp 
Each tetrahedron edge can be assigned an orientation pointing from the lower numbered tetrahedron vertex to the higher.
The parameter twistUp is 0 if the identification of this object and its parent in the tree preserves this orientation, or 1 if it does not. If this object has no parent, the value of twistUp is undefined.