libigl_Martin/include/igl/intersect.cpp

// 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/.
#include "intersect.h"
template <class M>
IGL_INLINE void igl::intersect(const M & A, const M & B, M & C)
{
  // Stupid O(size(A) * size(B)) to do it
  // Alec: This should be implemented by using unique and sort like `setdiff`
  M dyn_C(A.size() > B.size() ? A.size() : B.size(),1);
  // count of intersects
  int c = 0;
  // Loop over A
  for(int i = 0;i<A.size();i++)
  {
    // Loop over B
    for(int j = 0;j<B.size();j++)
    {
      if(A(i) == B(j))
      {
        dyn_C(c) = A(i);
        c++;
      }
    }
  }

  // resize output
  C.resize(c,1);
  // Loop over intersects
  for(int i = 0;i<c;i++)
  {
    C(i) = dyn_C(i);
  }
}

template <class M>
IGL_INLINE M igl::intersect(const M & A, const M & B)
{
  M C;
  intersect(A,B,C);
  return C;
}
#ifdef IGL_STATIC_LIBRARY
// Explicit template specialization
template Eigen::Matrix<int, -1, 1, 0, -1, 1> igl::intersect<Eigen::Matrix<int, -1, 1, 0, -1, 1> >(Eigen::Matrix<int, -1, 1, 0, -1, 1> const&, Eigen::Matrix<int, -1, 1, 0, -1, 1> const&); 
#endif