47 lines
1.6 KiB
C++
47 lines
1.6 KiB
C++
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// This file is part of libigl, a simple c++ geometry processing library.
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//
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// Copyright (C) 2016 Michael Rabinovich <michaelrabinovich27@gmail.com@gmail.com>
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//
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// This Source Code Form is subject to the terms of the Mozilla Public License
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// v. 2.0. If a copy of the MPL was not distributed with this file, You can
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// obtain one at http://mozilla.org/MPL/2.0/.
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#include "euler_characteristic.h"
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#include "edge_topology.h"
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#include "edges.h"
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template <typename Scalar, typename Index>
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IGL_INLINE int igl::euler_characteristic(
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const Eigen::PlainObjectBase<Scalar> & V,
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const Eigen::PlainObjectBase<Index> & F)
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{
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int euler_v = V.rows();
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Eigen::MatrixXi EV, FE, EF;
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igl::edge_topology(V, F, EV, FE, EF);
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int euler_e = EV.rows();
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int euler_f = F.rows();
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int euler_char = euler_v - euler_e + euler_f;
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return euler_char;
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}
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template <typename DerivedF>
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IGL_INLINE int igl::euler_characteristic(
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const Eigen::MatrixBase<DerivedF> & F)
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{
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const int nf = F.rows();
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const int nv = F.maxCoeff()+1;
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Eigen::Matrix<typename DerivedF::Scalar,Eigen::Dynamic,2> E;
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edges(F,E);
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const int ne = E.rows();
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return nv - ne + nf;
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}
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#ifdef IGL_STATIC_LIBRARY
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// Explicit template instantiation
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template int igl::euler_characteristic<Eigen::Matrix<double, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, -1, 0, -1, -1> >(Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> > const&);
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template int igl::euler_characteristic<Eigen::Matrix<int, -1, -1, 0, -1, -1> >(Eigen::MatrixBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> > const&);
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#endif
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