74 lines
2.2 KiB
C++
74 lines
2.2 KiB
C++
// This file is part of libigl, a simple c++ geometry processing library.
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//
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// Copyright (C) 2013 Alec Jacobson <alecjacobson@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 "is_symmetric.h"
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#include "find.h"
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template <typename T>
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IGL_INLINE bool igl::is_symmetric(const Eigen::SparseMatrix<T>& A)
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{
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if(A.rows() != A.cols())
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{
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return false;
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}
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assert(A.size() != 0);
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Eigen::SparseMatrix<T> AT = A.transpose();
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Eigen::SparseMatrix<T> AmAT = A-AT;
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//// Eigen screws up something with LLT if you try to do
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//SparseMatrix<T> AmAT = A-A.transpose();
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//// Eigen crashes at runtime if you try to do
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// return (A-A.transpose()).nonZeros() == 0;
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return AmAT.nonZeros() == 0;
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}
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template <typename DerivedA>
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IGL_INLINE bool igl::is_symmetric(
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const Eigen::PlainObjectBase<DerivedA>& A)
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{
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if(A.rows() != A.cols())
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{
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return false;
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}
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assert(A.size() != 0);
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return (A-A.transpose()).eval().nonZeros() == 0;
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}
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template <typename AType, typename epsilonT>
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IGL_INLINE bool igl::is_symmetric(
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const Eigen::SparseMatrix<AType>& A,
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const epsilonT epsilon)
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{
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using namespace Eigen;
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using namespace std;
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if(A.rows() != A.cols())
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{
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return false;
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}
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assert(A.size() != 0);
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SparseMatrix<AType> AT = A.transpose();
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SparseMatrix<AType> AmAT = A-AT;
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VectorXi AmATI,AmATJ;
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Matrix<AType,Dynamic,1> AmATV;
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find(AmAT,AmATI,AmATJ,AmATV);
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if(AmATI.size() == 0)
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{
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return true;
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}
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return AmATV.maxCoeff() < epsilon && AmATV.minCoeff() > -epsilon;
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}
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#ifdef IGL_STATIC_LIBRARY
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// Explicit template instantiation
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// generated by autoexplicit.sh
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template bool igl::is_symmetric<Eigen::Matrix<double, -1, -1, 0, -1, -1> >(Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 0, -1, -1> > const&);
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// generated by autoexplicit.sh
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template bool igl::is_symmetric<double>(Eigen::SparseMatrix<double, 0, int> const&);
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template bool igl::is_symmetric<double, double>(Eigen::SparseMatrix<double, 0, int> const&, double);
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template bool igl::is_symmetric<double, int>(Eigen::SparseMatrix<double, 0, int> const&, int);
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#endif
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