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/**************************************************************************
* *
* Regina - A Normal Surface Theory Calculator *
* Computational Engine *
* *
* Copyright (c) 1999-2008, 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 */
#include "manifold/ntorusbundle.h"
#include "subcomplex/nlayeredsurfacebundle.h"
#include "subcomplex/nlayering.h"
#include "subcomplex/ntxicore.h"
#include "triangulation/nisomorphism.h"
#include "triangulation/ntriangulation.h"
namespace regina {
namespace {
const NTxIDiagonalCore core_T_6_1(6, 1);
const NTxIDiagonalCore core_T_7_1(7, 1);
const NTxIDiagonalCore core_T_8_1(8, 1);
const NTxIDiagonalCore core_T_8_2(8, 2);
const NTxIDiagonalCore core_T_9_1(9, 1);
const NTxIDiagonalCore core_T_9_2(9, 2);
const NTxIDiagonalCore core_T_10_1(10, 1);
const NTxIDiagonalCore core_T_10_2(10, 2);
const NTxIDiagonalCore core_T_10_3(10, 3);
const NTxIParallelCore core_T_p;
}
NLayeredTorusBundle::~NLayeredTorusBundle() {
delete coreIso_;
}
NLayeredTorusBundle* NLayeredTorusBundle::isLayeredTorusBundle(
NTriangulation* tri) {
// Basic property checks.
if (! tri->isClosed())
return 0;
if (tri->getNumberOfVertices() > 1)
return 0;
if (tri->getNumberOfComponents() > 1)
return 0;
if (tri->getNumberOfTetrahedra() < 6)
return 0;
// We have a 1-vertex 1-component closed triangulation with at least
// six tetrahedra.
// Hunt for the core thin torus bundle.
NLayeredTorusBundle* ans;
if ((ans = hunt(tri, core_T_6_1)))
return ans;
if ((ans = hunt(tri, core_T_7_1)))
return ans;
if ((ans = hunt(tri, core_T_8_1)))
return ans;
if ((ans = hunt(tri, core_T_8_2)))
return ans;
if ((ans = hunt(tri, core_T_9_1)))
return ans;
if ((ans = hunt(tri, core_T_9_2)))
return ans;
if ((ans = hunt(tri, core_T_10_1)))
return ans;
if ((ans = hunt(tri, core_T_10_2)))
return ans;
if ((ans = hunt(tri, core_T_10_3)))
return ans;
if ((ans = hunt(tri, core_T_p)))
return ans;
return 0;
}
NLayeredTorusBundle* NLayeredTorusBundle::hunt(NTriangulation* tri,
const NTxICore& core) {
std::list<NIsomorphism*> isos;
if (! core.core().findAllSubcomplexesIn(*tri, isos))
return 0;
// Run through each isomorphism and look for the corresponding layering.
NMatrix2 matchReln;
for (std::list<NIsomorphism*>::const_iterator it = isos.begin();
it != isos.end(); it++) {
// Apply the layering to the lower boundary and see if it
// matches nicely with the upper.
NLayering layering(
tri->getTetrahedron((*it)->tetImage(core.bdryTet(1,0))),
(*it)->facePerm(core.bdryTet(1,0)) * core.bdryRoles(1,0),
tri->getTetrahedron((*it)->tetImage(core.bdryTet(1,1))),
(*it)->facePerm(core.bdryTet(1,1)) * core.bdryRoles(1,1));
layering.extend();
if (layering.matchesTop(
tri->getTetrahedron((*it)->tetImage(core.bdryTet(0,0))),
(*it)->facePerm(core.bdryTet(0,0)) * core.bdryRoles(0,0),
tri->getTetrahedron((*it)->tetImage(core.bdryTet(0,1))),
(*it)->facePerm(core.bdryTet(0,1)) * core.bdryRoles(0,1),
matchReln)) {
// It's a match!
NLayeredTorusBundle* ans = new NLayeredTorusBundle(core);
ans->coreIso_ = *it;
ans->reln_ = core.bdryReln(0) * matchReln *
core.bdryReln(1).inverse();
// Delete the remaining isomorphisms that we never even
// looked at.
for (it++; it != isos.end(); it++)
delete *it;
return ans;
}
// No match. Delete this isomorphism; we won't need it any more.
delete *it;
continue;
}
// Nothing found.
return 0;
}
NManifold* NLayeredTorusBundle::getManifold() const {
// Note that this one-liner appears again in getHomologyH1(), where
// we use the underlying NTorusBundle for homology calculations.
return new NTorusBundle(core_.parallelReln() * reln_);
}
NAbelianGroup* NLayeredTorusBundle::getHomologyH1() const {
// It's implemented in NTorusBundle, so ride on that for now.
// We'll implement it directly here in good time.
return NTorusBundle(core_.parallelReln() * reln_).getHomologyH1();
}
std::ostream& NLayeredTorusBundle::writeCommonName(std::ostream& out,
bool tex) const {
if (tex) {
out << "B_{";
core_.writeTeXName(out);
} else {
out << "B(";
core_.writeName(out);
}
out << " | " << reln_[0][0] << ',' << reln_[0][1];
out << " | " << reln_[1][0] << ',' << reln_[1][1];
return out << (tex ? "}" : ")");
}
void NLayeredTorusBundle::writeTextLong(std::ostream& out) const {
out << "Layered torus bundle: ";
writeName(out);
}
} // namespace regina
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