text: // This file is part of libigl, a simple c++ geometry processing library.
  // 
  // Copyright (C) 2013 Alec Jacobson <alecjacobson@gmail.com>
  // 
  // This Source Code Form is subject to the terms of the Mozilla Public License 
  // v. 2.0. If a copy of the MPL was not distributed with this file, You can 
  // obtain one at http://mozilla.org/MPL/2.0/.
  #ifndef IGL_EDGE_LENGTHS_H
  #define IGL_EDGE_LENGTHS_H
  #include "igl_inline.h"
  
  #include <Eigen/Dense>
  
  namespace igl
  {
    // Constructs a list of lengths of edges opposite each index in a face
    // (triangle/tet) list
    //
    // Templates:
    //   DerivedV derived from vertex positions matrix type: i.e. MatrixXd
    //   DerivedF derived from face indices matrix type: i.e. MatrixXi
    //   DerivedL derived from edge lengths matrix type: i.e. MatrixXd
    // Inputs:
    //   V  eigen matrix #V by 3
    //   F  #F by 2 list of mesh edges
    //    or
    //   F  #F by 3 list of mesh faces (must be triangles)
    //    or
    //   T  #T by 4 list of mesh elements (must be tets)
    // Outputs:
    //   L  #F by {1|3|6} list of edge lengths 
    //     for edges, column of lengths
    //     for triangles, columns correspond to edges [1,2],[2,0],[0,1]
    //     for tets, columns correspond to edges
    //     [3 0],[3 1],[3 2],[1 2],[2 0],[0 1]
    //
    template <typename DerivedV, typename DerivedF, typename DerivedL>
    IGL_INLINE void edge_lengths(
      const Eigen::PlainObjectBase<DerivedV>& V,
      const Eigen::PlainObjectBase<DerivedF>& F,
      Eigen::PlainObjectBase<DerivedL>& L);
  }
  
  #ifndef IGL_STATIC_LIBRARY
  #  include "edge_lengths.cpp"
  #endif
  
  #endif
  
  