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/**************************************************************************
* *
* Regina - A Normal Surface Theory Calculator *
* Computational Engine *
* *
* Copyright (c) 1999-2025, 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, see <https://www.gnu.org/licenses/>. *
* *
**************************************************************************/
/*! \file triangulation/example2.h
* \brief Offers some example 2-dimensional triangulations as starting
* points for testing code or getting used to Regina.
*/
#ifndef __REGINA_EXAMPLE2_H
#ifndef __DOXYGEN
#define __REGINA_EXAMPLE2_H
#endif
#include "regina-core.h"
#include "triangulation/dim2.h"
#include "triangulation/detail/example.h"
namespace regina {
/**
* Offers routines for constructing a variety of sample 2-dimensional
* triangulations.
*
* This is a specialisation of the generic Example class template; see the
* generic Example template documentation for a general overview of how the
* example triangulation classes work. In Python, you can read this generic
* documentation by looking at a higher dimension: try `help(Example5)`.
*
* This 2-dimensional specialisation offers significant extra functionality,
* by providing several more hard-coded constructions.
*
* \ingroup triangulation
*/
template <>
class Example<2> : public detail::ExampleBase<2> {
public:
/**
* Returns a triangulation of the given orientable surface.
*
* If the number of punctures is 0, then the resulting triangulation
* will be minimal (which, for positive genus, means there is exactly
* one vertex).
*
* \param genus the genus of the surface; this must be greater
* than or equal to zero.
* \param punctures the number of punctures in the surface;
* this must be greater than or equal to zero.
* \return the requested orientable surface.
*/
static Triangulation<2> orientable(
unsigned genus, unsigned punctures);
/**
* Returns a triangulation of the given non-orientable surface.
*
* If the number of punctures is 0 or 1, then the resulting
* triangulation will be minimal (which, with the exception of
* the projective plane, means there is exactly one vertex).
*
* \param genus the non-orientable genus of the surface, i.e.,
* the number of crosscaps that it contains; this must be greater
* than or equal to one.
* \param punctures the number of punctures in the surface;
* this must be greater than or equal to zero.
* \return the requested non-orientable surface.
*
* \author Alex He, B.B.
*/
static Triangulation<2> nonOrientable(
unsigned genus, unsigned punctures);
/**
* Returns the four-triangle 2-sphere formed from the boundary
* of a tetrahedron. This is identical to the triangulation
* returned by the generic routine simplicialSphere().
*
* \return the tetrahedral sphere.
*/
static Triangulation<2> sphereTetrahedron();
/**
* Returns the eight-triangle 2-sphere formed from the boundary
* of an octahedron.
*
* \return the octahedral sphere.
*/
static Triangulation<2> sphereOctahedron();
/**
* Returns a one-triangle disc.
* This is identical to the triangulation returned by the generic
* routine ball().
*
* \return the disc.
*/
static Triangulation<2> disc();
/**
* Returns a two-triangle annulus.
* This is identical to the triangulation returned by the generic
* routine ballBundle().
*
* \return the annulus.
*/
static Triangulation<2> annulus();
/**
* Returns a one-triangle Mobius band. This is identical to the
* triangulation returned by the generic routine twistedBallBundle().
*
* \return the Mobius band.
*/
static Triangulation<2> mobius();
/**
* Returns a two-triangle torus.
* This is identical to the triangulation returned by the generic
* routine sphereBundle().
*
* \return the torus.
*/
static Triangulation<2> torus();
/**
* Returns a two-triangle projective plane.
*
* \return the projective plane.
*/
static Triangulation<2> rp2();
/**
* Returns a two-triangle Klein bottle. This is identical to the
* triangulation returned by the generic routine twistedSphereBundle().
*
* \return the Klein bottle.
*/
static Triangulation<2> kb();
};
inline Triangulation<2> Example<2>::sphereTetrahedron() {
return simplicialSphere();
}
inline Triangulation<2> Example<2>::torus() {
return sphereBundle();
}
inline Triangulation<2> Example<2>::kb() {
return twistedSphereBundle();
}
inline Triangulation<2> Example<2>::disc() {
return ball();
}
inline Triangulation<2> Example<2>::annulus() {
return ballBundle();
}
inline Triangulation<2> Example<2>::mobius() {
return twistedBallBundle();
}
} // namespace regina
#endif
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