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/**************************************************************************
* *
* Regina - A Normal Surface Theory Calculator *
* Computational Engine *
* *
* Copyright (c) 1999-2016, 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. *
* *
* As an exception, when this program is distributed through (i) the *
* App Store by Apple Inc.; (ii) the Mac App Store by Apple Inc.; or *
* (iii) Google Play by Google Inc., then that store may impose any *
* digital rights management, device limits and/or redistribution *
* restrictions that are required by its terms of service. *
* *
* 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. *
* *
**************************************************************************/
/*! \file census/gluingperms.h
* \brief Deals with selecting gluing permutations to complement a
* particular pairing of facets of simplices in an n-manifold triangulation.
*/
#ifndef __GLUINGPERMS_H
#ifndef __DOXYGEN
#define __GLUINGPERMS_H
#endif
#include "regina-core.h"
#include "triangulation/facetspec.h"
#include "triangulation/forward.h"
#include "maths/perm.h"
namespace regina {
/**
* \weakgroup census
* @{
*/
/**
* Represents a specific set of gluing permutations to complement a
* particular pairwise matching of simplex facets. Given a pairwise
* matching of facets (as described by class FacetPairing<dim>),
* each facet that is matched with some other facet will have an associated
* permutation of (\a dim + 1) elements.
*
* If a facet is matched with some other facet, the two associated
* permutations in this set will be inverses. If a facet is left
* deliberately unmatched, it will have no associated permutation in this set.
*
* Such a set of permutations models part of the structure of a
* triangulation, in which each simplex facet that is glued to another
* facet has a corresponding gluing permutation (and the matched facet has
* the inverse gluing permutation).
*
* \headers Parts of this template class are implemented in a separate header
* (gluingperms-impl.h), which is not included automatically by
* this file. However, typical end users should never need this extra header,
* since Regina's calculation engine already includes explicit instantiations
* for \ref stddim "standard dimensions".
*
* \ifacespython Not available.
*
* \tparam dim the dimension of the underlying triangulation that is
* being modelled. This must be between 2 and 15 inclusive.
*/
template <int dim>
class GluingPerms {
protected:
const FacetPairing<dim>* pairing_;
/**< The facet pairing that this permutation set complements.
This is guaranteed to be the minimal representative of
its facet pairing isomorphism class. */
int* permIndices_;
/**< The index into array Perm<dim+1>::Sn_1 describing how each
simplex facet is glued to its partner. Note that this
is not a gluing permutation as such but rather a permutation
of 0,...,\a dim-1 only (see the routines gluingToIndex() and
indexToGluing() for conversions). If a permutation has not
yet been selected (e.g., if this permutation set is still
under construction) then this index is -1. */
bool inputError_;
/**< Has an error occurred during construction from an
input stream? */
public:
/**
* Creates a new set of gluing permutations that is a clone of
* the given permutation set.
*
* @param cloneMe the gluing permutations to clone.
*/
GluingPerms(const GluingPerms<dim>& cloneMe);
/**
* Reads a new set of gluing permutations from the given input
* stream. This routine reads data in the format written by
* dumpData().
*
* If the data found in the input stream is invalid or
* incorrectly formatted, the routine inputError() will return
* \c true but the contents of this object will be otherwise
* undefined.
*
* \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.
*
* @param in the input stream from which to read.
*/
GluingPerms(std::istream& in);
/**
* Deallocates any memory used by this structure.
*/
virtual ~GluingPerms();
/**
* Was an error found during construction from an input stream?
*
* This routine returns \c true if an input stream constructor was
* used to create this object but the data in the input stream
* was invalid or incorrectly formatted.
*
* If a different constructor was called (i.e., no input stream
* was used), then this routine will always return \c false.
*
* @return \c true if an error occurred during construction from
* an input stream, or \c false otherwise.
*/
bool inputError() const;
/**
* Returns the total number of simplices under consideration.
*
* @return the number of simplices under consideration.
*/
unsigned size() const;
/**
* Returns the specific pairing of simplex facets that this
* set of gluing permutations complements.
*
* @return the corresponding simplex facet pairing.
*/
const FacetPairing<dim>* facetPairing() const;
/**
* Returns the gluing permutation associated with the given
* simplex facet.
*
* \pre The given facet is actually paired with some other facet in
* the underlying pairwise matching (see routine facetPairing()).
* \pre The given facet is a real simplex
* facet (not boundary, before-the-start or past-the-end).
*
* @param source the simplex facet under investigation.
* @return the associated gluing permutation.
*/
Perm<dim+1> gluingPerm(const FacetSpec<dim>& source) const;
/**
* Returns the gluing permutation associated with the given
* simplex facet.
*
* \pre The given facet is actually paired with some other facet in
* the underlying pairwise matching (see routine facetPairing()).
*
* @param simp the simplex under investigation (this must be
* strictly less than the total number of simplices under
* consideration).
* @param facet the facet of the given simplex under
* investigation (between 0 and \a dim inclusive).
* @return the associated gluing permutation.
*/
Perm<dim+1> gluingPerm(unsigned simp, unsigned facet) const;
/**
* Returns a newly created triangulation as modelled by this set
* of gluing permutations and the associated simplex facet
* pairing.
*
* Each matched pair of facets and their associated permutations
* will be realised as two simplex facets in the triangulation glued
* together with the corresponding gluing permutation. Each
* unmatched facet will be realised as a boundary facet in the
* triangulation.
*
* It is the responsibility of the caller of this routine to
* delete this triangulation once it is no longer required.
*
* @return a newly created triangulation modelled by this structure.
*/
Triangulation<dim>* triangulate() const;
/**
* Dumps all internal data in a plain text format to the given
* output stream. This object can be recreated from this text
* data by calling the input stream constructor for this class.
*
* This routine may be useful for transferring objects from
* one processor to another.
*
* Note that subclass data is written after superclass data, so
* it is safe to dump data from a subclass and then recreate a
* new superclass object from that data (though subclass-specific
* information will of course be lost).
*
* \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.
*
* @param out the output stream to which the data should be
* written.
*/
virtual void dumpData(std::ostream& out) const;
protected:
/**
* Creates a new permutation set. All internal arrays will be
* allocated but not initialised.
*
* \pre The given facet pairing is connected, i.e., it is possible
* to reach any simplex from any other simplex via a
* series of matched facet pairs.
* \pre The given facet pairing is in canonical form as described
* by FacetPairing::isCanonical(). Note that all facet pairings
* constructed by FacetPairing::findAllPairings() are of this form.
*
* @param pairing the specific pairing of simplex facets
* that this permutation set will complement.
*/
GluingPerms(const FacetPairing<dim>* pairing);
/**
* Returns the index into array Perm<dim+1>::Sn_1 describing how the
* the given facet is joined to its partner.
*
* Note that this permutation is not a gluing permutation as such,
* but rather a permutation of 0,...,\a dim-1 only. For a real facet
* gluing permutation, see routine gluingPerm().
*
* \pre The given facet is a real simplex
* facet (not boundary, before-the-start or past-the-end).
*
* @param source the simplex facet under investigation.
* @return a reference to the corresponding array index.
*/
int& permIndex(const FacetSpec<dim>& source);
/**
* Returns the index into array Perm<dim+1>::Sn_1 describing how the
* the given facet is joined to its partner.
*
* Note that this permutation is not a gluing permutation as such,
* but rather a permutation of 0,...,\a dim-1 only. For a real facet
* gluing permutation, see routine gluingPerm().
*
* @param simp the simplex under investigation (this must be
* strictly less than the total number of simplices under
* consideration).
* @param facet the facet of the given simplex under
* investigation (between 0 and \a dim inclusive).
* @return a reference to the corresponding array index.
*/
int& permIndex(unsigned simp, unsigned facet);
/**
* Returns the index into array Perm<dim+1>::Sn_1 describing how the
* the given facet is joined to its partner.
*
* Note that this permutation is not a gluing permutation as such,
* but rather a permutation of 0,...,\a dim-1 only. For a real facet
* gluing permutation, see routine gluingPerm().
*
* \pre The given facet is a real simplex
* facet (not boundary, before-the-start or past-the-end).
*
* @param source the simplex facet under investigation.
* @return a reference to the corresponding array index.
*/
const int& permIndex(const FacetSpec<dim>& source) const;
/**
* Returns the index into array Perm<dim+1>::Sn_1 describing how the
* the given facet is joined to its partner.
*
* Note that this permutation is not a gluing permutation as such,
* but rather a permutation of 0,...,\a dim-1 only. For a real facet
* gluing permutation, see routine gluingPerm().
*
* @param simp the simplex under investigation (this must be
* strictly less than the total number of simplices under
* consideration).
* @param facet the facet of the given simplex under
* investigation (between 0 and \a dim inclusive).
* @return a reference to the corresponding array index.
*/
const int& permIndex(unsigned simp, unsigned facet) const;
/**
* Returns the index into array Perm<dim+1>::Sn_1 corresponding to
* the given gluing permutation from the given facet to its
* partner. This need not be the index into Perm<dim+1>::Sn_1 that
* is currently stored for the given facet.
*
* Indices into array Perm<dim+1>::Sn_1 are stored internally in the
* array \a permIndices_. Full gluing permutations on the other
* hand are used in constructing triangulations.
*
* \pre The given simplex facet has a partner according to
* the underlying facet pairing, i.e., is not a boundary facet.
* \pre If the given simplex facet and its partner are facets
* \a x and \a y of their respective simplices, then the
* given gluing permutation maps \a x to \a y.
*
* @param source the simplex facet under investigation.
* @param gluing a possible gluing permutation from the given
* simplex facet to its partner according to the underlying
* facet pairing.
* @return the index into Perm<dim+1>::Sn_1 corresponding to the
* given gluing permutation; this will be between 0 and \a dim!-1
* inclusive.
*/
int gluingToIndex(const FacetSpec<dim>& source,
const Perm<dim+1>& gluing) const;
/**
* Returns the index into array Perm<dim+1>::Sn_1 corresponding to
* the given gluing permutation from the given facet to its
* partner. This need not be the index into Perm<dim+1>::Sn_1 that
* is currently stored for the given facet.
*
* Indices into array Perm<dim+1>::Sn_1 are stored internally in the
* array \a permIndices_. Full gluing permutations on the other
* hand are used in constructing triangulations.
*
* \pre The given simplex facet has a partner according to
* the underlying facet pairing, i.e., is not a boundary facet.
* \pre If the given simplex facet and its partner are facets
* \a x and \a y of their respective simplices, then the
* given gluing permutation maps \a x to \a y.
*
* @param simp the simplex under investigation; this must be
* strictly less than the total number of simplices under
* consideration.
* @param facet the facet of the given simplex under
* investigation; this must be between 0 and \a dim inclusive.
* @param gluing a possible gluing permutation from the given
* simplex facet to its partner according to the underlying
* facet pairing.
* @return the index into Perm<dim+1>::Sn_1 corresponding to the
* given gluing permutation; this will be between 0 and \a dim!-1
* inclusive.
*/
int gluingToIndex(unsigned simp, unsigned facet,
const Perm<dim+1>& gluing) const;
/**
* Returns the gluing permutation from the given facet to its
* partner that corresponds to the given index into array
* Perm<dim+1>::Sn_1. This index into Perm<dim+1>::Sn_1 need not
* be the index that is currently stored for the given facet.
*
* Indices into array Perm<dim+1>::Sn_1 are stored internally in the
* array \a permIndices_. Full gluing permutations on the other
* hand are used in constructing triangulations.
*
* If the given simplex facet and its partner according to
* the underlying facet pairing are facets \a x and \a y of their
* respective simplices, then the resulting gluing permutation
* will map \a x to \a y.
*
* \pre The given simplex facet has a partner according to
* the underlying facet pairing, i.e., is not a boundary facet.
*
* @param source the simplex facet under investigation.
* @param index an index into Perm<dim+1>::Sn_1; this must be
* between 0 and \a dim!-1 inclusive.
* @return the gluing permutation corresponding to the given
* index into Perm<dim+1>::Sn_1.
*/
Perm<dim+1> indexToGluing(const FacetSpec<dim>& source, int index)
const;
/**
* Returns the gluing permutation from the given facet to its
* partner that corresponds to the given index into array
* Perm<dim+1>::Sn_1. This index into Perm<dim+1>::Sn_1 need not
* be the index that is currently stored for the given facet.
*
* Indices into array Perm<dim+1>::Sn_1 are stored internally in the
* array \a permIndices_. Full gluing permutations on the other
* hand are used in constructing triangulations.
*
* If the given simplex facet and its partner according to
* the underlying facet pairing are facets \a x and \a y of their
* respective simplices, then the resulting gluing permutation
* will map \a x to \a y.
*
* \pre The given simplex facet has a partner according to
* the underlying facet pairing, i.e., is not a boundary facet.
*
* @param simp the simplex under investigation; this must be
* strictly less than the total number of simplices under
* consideration.
* @param facet the facet of the given simplex under
* investigation; this must be between 0 and \a dim inclusive.
* @param index an index into Perm<dim+1>::Sn_1; this must be
* between 0 and \a dim!-1 inclusive.
* @return the gluing permutation corresponding to the given
* index into Perm<dim+1>::Sn_1.
*/
Perm<dim+1> indexToGluing(unsigned simp, unsigned facet, int index)
const;
};
/**
* Deprecated typedef for backward compatibility. This typedef will
* be removed in a future release of Regina.
*
* \deprecated Instead of the old type alias NGenericGluingPerms<dim>,
* you should use the new class name GluingPerms<dim>.
*/
template <int dim>
using NGenericGluingPerms REGINA_DEPRECATED = GluingPerms<dim>;
/**
* Deprecated typedef for backward compatibility. This typedef will
* be removed in a future release of Regina.
*
* \deprecated Instead of the old typedef Dim2GluingPerms, you should use
* the full class name GluingPerms<2>.
*/
REGINA_DEPRECATED typedef GluingPerms<2> Dim2GluingPerms;
/**
* Deprecated typedef for backward compatibility. This typedef will
* be removed in a future release of Regina.
*
* \deprecated Instead of the old typedef NGluingPerms, you should use
* the full class name GluingPerms<3>.
*/
REGINA_DEPRECATED typedef GluingPerms<3> NGluingPerms;
/**
* Deprecated typedef for backward compatibility. This typedef will
* be removed in a future release of Regina.
*
* \deprecated Instead of the old typedef Dim4GluingPerms, you should use
* the full class name GluingPerms<4>.
*/
REGINA_DEPRECATED typedef GluingPerms<4> Dim4GluingPerms;
/*@}*/
// Indicate which templates we explicitly instantiate in the shared library.
#ifndef __DOXYGEN
extern template class REGINA_API GluingPerms<2>;
extern template class REGINA_API GluingPerms<3>;
extern template class REGINA_API GluingPerms<4>;
#endif // __DOXYGEN
// Inline functions for GluingPerms
template <int dim>
inline GluingPerms<dim>::GluingPerms(
const FacetPairing<dim>* pairing) :
pairing_(pairing),
permIndices_(new int[pairing->size() * (dim + 1)]),
inputError_(false) {
}
template <int dim>
inline GluingPerms<dim>::~GluingPerms() {
delete[] permIndices_;
}
template <int dim>
inline bool GluingPerms<dim>::inputError() const {
return inputError_;
}
template <int dim>
inline unsigned GluingPerms<dim>::size() const {
return pairing_->size();
}
template <int dim>
inline const FacetPairing<dim>* GluingPerms<dim>::facetPairing()
const {
return pairing_;
}
template <int dim>
inline Perm<dim+1> GluingPerms<dim>::gluingPerm(
const FacetSpec<dim>& source) const {
return indexToGluing(source, permIndex(source));
}
template <int dim>
inline Perm<dim+1> GluingPerms<dim>::gluingPerm(
unsigned simp, unsigned facet) const {
return indexToGluing(simp, facet, permIndex(simp, facet));
}
template <int dim>
inline int& GluingPerms<dim>::permIndex(const FacetSpec<dim>& source) {
return permIndices_[(dim + 1) * source.simp + source.facet];
}
template <int dim>
inline int& GluingPerms<dim>::permIndex(unsigned simp, unsigned facet) {
return permIndices_[(dim + 1) * simp + facet];
}
template <int dim>
inline const int& GluingPerms<dim>::permIndex(
const FacetSpec<dim>& source) const {
return permIndices_[(dim + 1) * source.simp + source.facet];
}
template <int dim>
inline const int& GluingPerms<dim>::permIndex(
unsigned simp, unsigned facet) const {
return permIndices_[(dim + 1) * simp + facet];
}
template <int dim>
inline Perm<dim+1> GluingPerms<dim>::indexToGluing(
const FacetSpec<dim>& source, int index) const {
return Perm<dim+1>(pairing_->dest(source).facet, dim) *
Perm<dim+1>::Sn_1[index] * Perm<dim+1>(source.facet, dim);
}
template <int dim>
inline Perm<dim+1> GluingPerms<dim>::indexToGluing(
unsigned simp, unsigned facet, int index) const {
return Perm<dim+1>(pairing_->dest(simp, facet).facet, dim) *
Perm<dim+1>::Sn_1[index] * Perm<dim+1>(facet, dim);
}
} // namespace regina
#endif
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