[ublas] sparse matrix element check

From: Nizar Khalifa Sallem (nksallem_at_[hidden])
Date: 2008-07-21 11:39:18

Hi,
I am using sparse matrix to store size 2 vectors and I am facing a 
little problem.
I want just to, let's say, dsplay element of the matrix only if they 
exist, but I couldn't find any method to access non zero element indexes 
or to make existency check. Am I wrong, does such methods exist ?
Here is a sample code:
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void TestProxies::testSparseMatrix2() {
  using namespace boost::numeric::ublas;
  compressed_matrix<bounded_vector<double, 2> > m(3,3,2);
  bounded_vector<double, 2> v1, v2;

  v1(0) = 1.1;
  v1(1) = 2.1;
  v2(0) = 2.13;
  v2(1) = 3.14;
  m(0,0) = v1;
  m(2,1) = v2;
  std::cout << m << std::endl;
  for (unsigned i = 0; i < m.size1 (); ++ i) {
    for (unsigned j = 0; j < m.size2 (); ++ j) {
      if(m(i,j)) {//it would worked fine if m elements were double and 
not vectors
        std::cout << (bounded_vector<double, 2>) m(i,j) << std::endl;
    }
  }
}
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Thanks