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/**************************************************************************
* *
* Regina - A Normal Surface Theory Calculator *
* Computational Engine *
* *
* Copyright (c) 1999-2011, Ben Burton *
* For further details contact Ben Burton (bab@debian.org). *
* *
* This program is free software; you can redistribute it and/or *
* modify it under the terms of the GNU General Public License as *
* published by the Free Software Foundation; either version 2 of the *
* License, or (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, but *
* WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* General Public License for more details. *
* *
* You should have received a copy of the GNU General Public *
* License along with this program; if not, write to the Free *
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, *
* MA 02110-1301, USA. *
* *
**************************************************************************/
/* end stub */
/*! \file split/nsigcensus.h
* \brief Deals with forming a census of splitting surface signatures.
*/
#ifndef __NSIGCENSUS_H
#ifndef __DOXYGEN
#define __NSIGCENSUS_H
#endif
#include <list>
#include "regina-core.h"
#include "split/nsignature.h"
#include "split/nsigisomorphism.h"
namespace regina {
/**
* \weakgroup split
* @{
*/
/**
* A list of partial isomorphisms on splitting surface signatures.
*/
typedef std::list<NSigPartialIsomorphism*> NSigIsoList;
/**
* A routine used to do arbitrary processing upon a splitting surface
* signature and its automorphisms. Such routines are used to process
* signatures found when running a signature census.
*
* The first parameter passed should be a splitting surface signature.
* The second parameter should be a list of all automorphisms of this signature.
* The third parameter may contain arbitrary data as passed to
* formSigCensus().
*/
typedef void (*UseSignature)(const NSignature&, const NSigIsoList&, void *);
/**
* Forms a census of all splitting surface signatures of the given order.
* The order of a signature is the number of quads in the corresponding
* splitting surface.
*
* Each signature will be produced precisely once up to equivalence.
* Signatures are considered equivalent if they are related by some
* combination of:
* - relabelling symbols;
* - rotating an individual cycle;
* - inverting an individual cycle (i.e., reversing the cycle and
* changing the case of each symbol in the cycle);
* - reversing all cycles without changing the case of any symbols.
*
* Each signature produced will have its cycles ordered by decreasing
* length. Each cycle will have at least half of its symbols lower-case.
*
* For each signature that is generated, routine \a use (as passed to this
* function) will be called with that signature and its automorphisms as
* arguments.
*
* \warning Currently upper-case symbols in signatures are not supported
* by this routine; only signatures whose symbols are all lower-case will
* be produced.
*
* \todo \feature Add support for symbols of differing case.
*
* \ifacespython Not present.
*
* @param order the order of signatures to generate.
* @param use the function to call upon each signature that is found.
* The first parameter passed to this function will be a splitting
* surface signature. The second parameter will be a list of all its
* automorphisms. The third parameter will be parameter \a useArgs as
* was passed to this routine.
* @param useArgs the pointer to pass as the final parameter for the
* function \a use which will be called upon each signature found.
* @return the total number of non-equivalent signatures that were found.
*/
REGINA_API unsigned long formSigCensus(unsigned order, UseSignature use,
void* useArgs = 0);
/**
* A utility class used by formSigCensus(). Other routines should never
* refer to this class directly. It is used to store temporary
* information when forming the census.
*
* \ifacespython Not present.
*/
class REGINA_API NSigCensus {
private:
NSignature sig;
/**< The signature being constructed. */
unsigned nextLabel;
/**< The first symbol that has not yet been used. */
unsigned* used;
/**< The number of times each symbol has been used so far. */
NSigIsoList* automorph;
/**< List <tt>automorph[k]</tt> represents all automorphisms
of the first \a k cycle groups of the partially formed
signature. */
UseSignature use;
/**< The argument passed to formSigCensus(). */
void* useArgs;
/**< The argument passed to formSigCensus(). */
unsigned long totalFound;
/**< The total number of signatures found so far. */
public:
/**
* Deallocates any memory used specifically by this structure.
*/
~NSigCensus();
/**
* Runs a complete signature census generation. At most one
* copy of this routine should be running at any given time for
* a particular NSigCensus.
*
* @param param this parameter is ignored.
* @return 0.
*/
void* run(void* param);
private:
/**
* Creates a new structure to form a signature census.
* All parameters not explained are taken directly from
* formSigCensus().
*
* \pre order is at least 1.
*/
NSigCensus(unsigned order, UseSignature newUse, void* newUseArgs);
/**
* Empty the list <tt>automorph[sig.nCycleGroups]</tt> and
* destroy the corresponding partial isomorphisms.
*/
void clearTopAutomorphisms();
/**
* Extend the automorphisms in list
* <tt>automorph[sig.nCycleGroups - 1]</tt> to form the
* automorphisms in list <tt>automorph[sig.nCycleGroups]</tt>.
*
* If in the processing of extending these automorphisms it is
* discovered that the partial signature <tt>sig</tt> is not in
* canonical form, \c false will be returned and the contents of
* list <tt>automorph[sig.nCycleGroups]</tt> will be undefined.
*
* @return \c true if and only if it was confirmed during
* processing that the partial signature <tt>sig</tt> is in
* canonical form.
*/
bool extendAutomorphisms();
/**
* Extends the partial signature created so far to add a new
* cycle.
*
* @param cycleLen the length of the new cycle to add.
* @param newCycleGroup \c true if and only if the new cycle
* begins a new cycle group.
* @param startPos the position within the list of symbols
* that make up the signature at which the new cycle will begin.
*/
void tryCycle(unsigned cycleLen, bool newCycleGroup, unsigned startPos);
friend unsigned long formSigCensus(unsigned order, UseSignature use,
void* useArgs);
};
/*@}*/
// Inline functions for NSigCensus
inline NSigCensus::NSigCensus(unsigned order, UseSignature newUse,
void* newUseArgs) : sig(order), used(new unsigned[order]),
automorph(new NSigIsoList[order + 2]), use(newUse),
useArgs(newUseArgs) {
}
inline NSigCensus::~NSigCensus() {
delete[] used;
delete[] automorph;
}
} // namespace regina
#endif
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