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			73 lines
		
	
	
	
		
			2.2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			73 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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| 
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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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| 
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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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| 
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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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|   
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|   return AmATV.maxCoeff() < epsilon && AmATV.minCoeff() > -epsilon;
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| }
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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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