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/**************************************************************************
* *
* Regina  A Normal Surface Theory Calculator *
* Computational Engine *
* *
* Copyright (c) 19992016, 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 021101301, USA. *
* *
**************************************************************************/
/*! \file enumerate/enumconstraints.h
* \brief Deals with validity constraints in polytope vertex enumeration.
*/
#ifndef __ENUMCONSTRAINTS_H
#ifndef __DOXYGEN
#define __ENUMCONSTRAINTS_H
#endif
#include <cstddef>
#include <set>
#include <vector>
#include "reginacore.h"
namespace regina {
/**
* \weakgroup enumerate
* @{
*/
/**
* Represents an individual validity constraint for use with
* polytope vertex enumeration.
*
* Vertex enumeration routines such as
* DoubleDescription::enumerateExtremalRays() take a cone (specifically
* the nonnegative orthant), form the intersection of that cone with a
* given linear subspace, and return the extremal rays of the new cone
* that results.
*
* In some cases we are only interested in \e valid rays of the new cone.
* The EnumConstraints class stores a number of "validity constraints";
* a ray is then "valid" if it satisfies all of these constraints.
*
* Each individual constraint is presented as a set of integers; the
* meaning of such a constraint is as follows. We number the facets of
* the original cone 0,1,2,... (where the <i>i</i>th facet is the plane
* perpendicular to the <i>i</i>th coordinate axis). If a constraint is
* described by the integers \a x, \a y, \a z, ..., then it indicates that a
* ray can only lie outside at most one of the facets numbered
* \a x, \a y, \a z, ... .
*
* In practice, this allows us to represent constraints in normal
* surface theory. For instance, to insist that some tetrahedron
* contains at most one quadrilateral disc type, we add a constraint
* with three integers, representing the original facets
* \a q1=0, \a q2=0, \a q3=0 (where \a q1, \a q2 and \a q3 are the three
* quadrilateral coordinates for that tetrahedron).
*
* The EnumConstraints class is simply a std::vector of constraints,
* where each constraint is a std::set of unsigned integers. Typically
* one will create a vector containing the desired number of constraints
* and then walk through each constraint, filling the sets as appropriate.
*
* \ifacespython Not present.
*/
class REGINA_API EnumConstraints :
public std::vector<std::set<unsigned long> > {
public:
/**
* Creates an empty list of constraints.
*/
EnumConstraints();
/**
* Creates a new list of constraints with the given size.
* Each constraint will be initialised to an empty set.
*
* @param size the number of constraints to include in the new list.
*/
EnumConstraints(size_t size);
};
/**
* Deprecated typedef for backward compatibility. This typedef will
* be removed in a future release of Regina.
*
* \deprecated The class NEnumConstraintList has now been renamed to
* EnumConstraints.
*/
REGINA_DEPRECATED typedef EnumConstraints NEnumConstraintList;
/*@}*/
// Inline functions for EnumConstraints
inline EnumConstraints::EnumConstraints() {
}
inline EnumConstraints::EnumConstraints(size_t size) :
std::vector<std::set<unsigned long> >(size) {
}
} // namespace regina
#endif
