denseToSparse() [1/2]

template<typename RingType>

void ConcreteVectorArithmetic< RingType >::denseToSparse ( ElementArray & dense, ElementArray & sparse, int *& comps, int first, int last ) const

inline

Definition at line 353 of file VectorArithmetic.hpp.

  {
    auto& dvec = * elementArray(dense);
    
    int len = 0;
    
    // first can be -1 if the row is zero.  in this case, we should
    // not be accessing dense[i] for i negative.
    for (int i = first; i >= 0 and i <= last; i++)
    if (not mRing->is_zero(dvec[i])) len++;
 
    //comps = f4Vec.allocate(len);
    comps = new int[len];
 
    sparse = allocateElementArray(len);
    auto& svec = * elementArray(sparse);
 
    int next = 0;
    for (int i = first; i >= 0 and i <= last; i++)
      if (not mRing->is_zero(dvec[i]))
    {
      mRing->set(svec[next],dvec[i]);
      comps[next] = i;
      ++next;
      mRing->set_zero(dvec[i]);
    }
  }

References allocateElementArray(), dvec(), elementArray(), and mRing.