C++ vector_expression类代码示例

void assign(
    vector_expression<V>& v, vector_expression<E> const& e,
    dense_random_access_iterator_tag, packed_random_access_iterator_tag
) {
    SIZE_CHECK(v().size() == e().size());
    typedef typename E::const_iterator EIterator;
    typedef typename V::scalar_type scalar_type;
    EIterator eiter = e.begin();
    EIterator eend = e.end();
    //special case:
    //right hand side is completely 0
    if(eiter == eend) {
        v().clear();
        return;
    }
    EIterator viter = v.begin();
    EIterator vend = v.end();

    //set the first elements to zero
    for(; viter.index() != eiter.index(); ++viter) {
        *viter= scalar_type/*zero*/();
    }
    //copy contents of right-hand side
    for(; eiter != eend; ++eiter,++viter) {
        *viter= *eiter;
    }

    for(; viter!= vend; ++viter) {
        *viter= scalar_type/*zero*/();
    }
}

void assign(
	vector_expression<V>& v, vector_expression<E> const& e, 
	packed_random_access_iterator_tag, packed_random_access_iterator_tag
) {
	SIZE_CHECK(v().size() == e().size());
	typedef typename E::const_iterator EIterator;
	EIterator eiter = e.begin();
	EIterator eend = e.end();
	//special case:
	//right hand side is completely 0
	if(eiter == eend){
		v().clear();
		return;
	}
	EIterator viter = v.begin();
	EIterator vend = v.end();
	
	//check for compatible layout
	SIZE_CHECK(vend-viter);//empty ranges can't be compatible
	//check whether the right hand side range is included in the left hand side range
	SIZE_CHECK(viter.index() <= eiter.index());
	SIZE_CHECK(viter.index()+(vend-viter) >= eiter.index()+(eend-eiter));
	
	//copy contents of right-hand side
	viter += eiter.index()-viter.index();
	for(;eiter != eend; ++eiter,++viter){
		*viter= *eiter;
	}
}

 viennacl::vector<SCALARTYPE, ALIGNMENT> 
 viennacl::vector<SCALARTYPE, ALIGNMENT>::operator-(const vector_expression< const hankel_matrix<SCALARTYPE, MAT_ALIGNMENT>,
                                                                             const vector<SCALARTYPE, ALIGNMENT>,
                                                                             op_prod> & proxy) 
 {
   assert(proxy.get_lhs().size1() == size());
   vector<SCALARTYPE, ALIGNMENT> result(size());
   viennacl::linalg::prod_impl(proxy.lhs(), proxy.rhs(), result);
   result = *this - result;
   return result;
 }

    vcl_size_t size(vector_expression<LHS, const int, op_matrix_diag> const & proxy)
    {
      int k = proxy.rhs();
      int A_size1 = static_cast<int>(size1(proxy.lhs()));
      int A_size2 = static_cast<int>(size2(proxy.lhs()));

      int row_depth = std::min(A_size1, A_size1 + k);
      int col_depth = std::min(A_size2, A_size2 - k);

      return std::min(row_depth, col_depth);
    }

 static void apply(vector_base<T> & lhs, vector_expression<const vandermonde_matrix<T, A>, const vector_base<T>, op_prod> const & rhs)
 {
   // check for the special case x = A * x
   if (viennacl::traits::handle(lhs) == viennacl::traits::handle(rhs.rhs()))
   {
     viennacl::vector<T> temp(lhs);
     viennacl::linalg::prod_impl(rhs.lhs(), rhs.rhs(), temp);
     lhs = temp;
   }
   else
     viennacl::linalg::prod_impl(rhs.lhs(), rhs.rhs(), lhs);
 }

 typename viennacl::enable_if<    viennacl::is_any_matrix<LHS>::value
                               && viennacl::is_any_dense_nonstructured_vector<RHS>::value,
                               vcl_size_t >::type
 size(vector_expression<const LHS, const RHS, op_prod> const & proxy)  //matrix-vector product
 {
   return proxy.lhs().size1();
 }

      void element_op(vector_base<T> & vec1,
                      vector_expression<const vector_base<T>, const vector_base<T>, op_element_binary<OP> > const & proxy)
      {
        typedef T                                              value_type;
        typedef viennacl::linalg::detail::op_applier<op_element_binary<OP> >    OpFunctor;

        value_type       * data_vec1 = detail::extract_raw_pointer<value_type>(vec1);
        value_type const * data_vec2 = detail::extract_raw_pointer<value_type>(proxy.lhs());
        value_type const * data_vec3 = detail::extract_raw_pointer<value_type>(proxy.rhs());

        std::size_t start1 = viennacl::traits::start(vec1);
        std::size_t inc1   = viennacl::traits::stride(vec1);
        std::size_t size1  = viennacl::traits::size(vec1);

        std::size_t start2 = viennacl::traits::start(proxy.lhs());
        std::size_t inc2   = viennacl::traits::stride(proxy.lhs());

        std::size_t start3 = viennacl::traits::start(proxy.rhs());
        std::size_t inc3   = viennacl::traits::stride(proxy.rhs());

#ifdef VIENNACL_WITH_OPENMP
        #pragma omp parallel for if (size1 > VIENNACL_OPENMP_VECTOR_MIN_SIZE)
#endif
        for (std::size_t i = 0; i < size1; ++i)
          OpFunctor::apply(data_vec1[i*inc1+start1], data_vec2[i*inc2+start2], data_vec3[i*inc3+start3]);
      }

void element_op(vector_base<NumericT> & vec1,
                vector_expression<const vector_base<NumericT>, const vector_base<NumericT>, op_element_unary<OpT> > const & proxy)
{
  typedef NumericT      value_type;
  typedef viennacl::linalg::detail::op_applier<op_element_unary<OpT> >    OpFunctor;

  value_type       * data_vec1 = detail::extract_raw_pointer<value_type>(vec1);
  value_type const * data_vec2 = detail::extract_raw_pointer<value_type>(proxy.lhs());

  vcl_size_t start1 = viennacl::traits::start(vec1);
  vcl_size_t inc1   = viennacl::traits::stride(vec1);
  vcl_size_t size1  = viennacl::traits::size(vec1);

  vcl_size_t start2 = viennacl::traits::start(proxy.lhs());
  vcl_size_t inc2   = viennacl::traits::stride(proxy.lhs());

#ifdef VIENNACL_WITH_OPENMP
  #pragma omp parallel for if (size1 > VIENNACL_OPENMP_VECTOR_MIN_SIZE)
#endif
  for (long i = 0; i < static_cast<long>(size1); ++i)
    OpFunctor::apply(data_vec1[static_cast<vcl_size_t>(i)*inc1+start1], data_vec2[static_cast<vcl_size_t>(i)*inc2+start2]);
}

vcl_size_t size(vector_expression<const matrix_expression<const LhsT, const RhsT, OpT>,
                                  const vector_base<NumericT>,
                                  op_prod> const & proxy)
{
  return size1(proxy.lhs());
}

bool op_aliasing(vector_base<NumericT> const & lhs, vector_expression<const LhsT, const RhsT, OpT> const & rhs)
{
  return op_aliasing(lhs, rhs.lhs()) || op_aliasing(lhs, rhs.rhs());
}