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# Regina - A Normal Surface Theory Calculator
# Python Test Suite Component
#
# Copyright (c) 2007-2008, Ben Burton
# For further details contact Ben Burton (bab@debian.org).
#
# Tests different Euler characteristic calculations.
#
# This file is a single component of Regina's python test suite. To run
# the python test suite, move to the main python directory in the source
# tree and run "make check".
#
# 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.
def printEuler(t, name):
print t.getEulerCharTri(), t.getEulerCharManifold(), \
'---', name
# Consistency check, while we're here.
eHom = regina.NHomologicalData(t).getEulerChar()
if eHom != t.getEulerCharManifold():
print 'ERROR: NTriangulation::getEulerCharManifold() and'
print ' NHomologicalData.getEulerChar() disagree!'
print 'Euler characteristics for triangulation vs compact manifold:'
# Empty:
printEuler(regina.NTriangulation(), "Empty triangulation")
# Closed:
printEuler(regina.NExampleTriangulation.lens8_3(), "L(8,3)")
printEuler(regina.NExampleTriangulation.rp2xs1(), "RP2 x S1")
# Bounded:
printEuler(regina.NExampleTriangulation.solidKleinBottle(),
"Solid Klein bottle")
printEuler(regina.NExampleTriangulation.lst3_4_7(), "LST(3,4,7)")
tri = regina.NTriangulation()
tri.addTetrahedron(regina.NTetrahedron())
printEuler(tri, "Solid ball")
# Ideal:
printEuler(regina.NExampleTriangulation.figureEightKnotComplement(),
"Figure eight knot complement")
printEuler(regina.NExampleTriangulation.whiteheadLinkComplement(),
"Whitehead link complement")
printEuler(regina.NExampleTriangulation.gieseking(),
"Gieseking manifold")
printEuler(regina.NExampleTriangulation.cuspedGenusTwoTorus(),
"Cusped genus two torus")
# Edge joined to itself:
tri = regina.NTriangulation()
t = regina.NTetrahedron()
t.joinTo(0, t, regina.NPerm(1,0,3,2))
t.joinTo(2, t, regina.NPerm(1,0,3,2))
tri.addTetrahedron(t)
printEuler(tri, "Invalid edge")
# Subdivide to obtain a valid triangulation:
tri.barycentricSubdivision()
printEuler(tri, "Two projective plane cusps")
# Invalid boundary vertex links:
tri = regina.NTriangulation()
t = regina.NTetrahedron()
s = regina.NTetrahedron()
t.joinTo(3, s, regina.NPerm(0,1,2,3))
t.joinTo(2, s, regina.NPerm(0,3,1,2))
tri.addTetrahedron(t)
tri.addTetrahedron(s)
printEuler(tri, "Pinched solid torus")
tri = regina.NTriangulation()
t = regina.NTetrahedron()
s = regina.NTetrahedron()
t.joinTo(3, s, regina.NPerm(0,1,2,3))
t.joinTo(2, s, regina.NPerm(0,2,1,3))
tri.addTetrahedron(t)
tri.addTetrahedron(s)
printEuler(tri, "Pinched solid Klein bottle")
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