ViennaCL - The Vienna Computing Library  1.2.0
Public Types | Public Member Functions | Protected Attributes
const_vector_iterator< SCALARTYPE, ALIGNMENT > Class Template Reference

A STL-type const-iterator for vector elements. Elements can be accessed, but cannot be manipulated. VERY SLOW!! More...

#include <vector.hpp>

Inheritance diagram for const_vector_iterator< SCALARTYPE, ALIGNMENT >:
vector_iterator< SCALARTYPE, ALIGNMENT >

Public Types

typedef scalar< SCALARTYPE > value_type
typedef long difference_type

Public Member Functions

 const_vector_iterator ()
 const_vector_iterator (vector< SCALARTYPE, ALIGNMENT > const &vec, cl_uint index)
 Constructor.
 const_vector_iterator (viennacl::ocl::handle< cl_mem > const &elements, cl_uint index)
value_type operator* (void) const
self_type operator++ (void)
self_type operator++ (int)
bool operator== (self_type const &other) const
bool operator!= (self_type const &other) const
difference_type operator- (self_type const &other) const
self_type operator+ (difference_type diff) const
std::size_t index () const
viennacl::ocl::handle< cl_mem >
const & 
handle () const

Protected Attributes

viennacl::ocl::handle< cl_mem > elements_
 The index of the entry the iterator is currently pointing to.
std::size_t index_

Detailed Description

template<class SCALARTYPE, unsigned int ALIGNMENT>
class viennacl::const_vector_iterator< SCALARTYPE, ALIGNMENT >

A STL-type const-iterator for vector elements. Elements can be accessed, but cannot be manipulated. VERY SLOW!!

Every dereference operation initiates a transfer from the GPU to the CPU. The overhead of such a transfer is around 50us, so 20.000 dereferences take one second. This is four orders of magnitude slower than similar dereferences on the CPU. However, increments and comparisons of iterators is as fast as for CPU types. If you need a fast iterator, copy the whole vector to the CPU first and iterate over the CPU object, e.g. std::vector<float> temp; copy(gpu_vector, temp); for (std::vector<float>::const_iterator iter = temp.begin(); iter != temp.end(); ++iter) { //do something } Note that you may obtain inconsistent data if entries of gpu_vector are manipulated elsewhere in the meanwhile.

Template Parameters
SCALARTYPEThe underlying floating point type (either float or double)
ALIGNMENTAlignment of the underlying vector,
See Also
vector

Member Typedef Documentation

typedef long difference_type
typedef scalar<SCALARTYPE> value_type

Constructor & Destructor Documentation

const_vector_iterator ( vector< SCALARTYPE, ALIGNMENT > const &  vec,
cl_uint  index 
)
inline

Constructor.

Parameters
vecThe vector over which to iterate
indexThe starting index of the iterator
const_vector_iterator ( viennacl::ocl::handle< cl_mem > const &  elements,
cl_uint  index 
)
inline

Member Function Documentation

viennacl::ocl::handle<cl_mem> const& handle ( ) const
inline
std::size_t index ( ) const
inline
bool operator!= ( self_type const &  other) const
inline
value_type operator* ( void  ) const
inline
self_type operator+ ( difference_type  diff) const
inline
self_type operator++ ( void  )
inline
self_type operator++ ( int  )
inline
difference_type operator- ( self_type const &  other) const
inline
bool operator== ( self_type const &  other) const
inline

Field Documentation

viennacl::ocl::handle<cl_mem> elements_
protected

The index of the entry the iterator is currently pointing to.

std::size_t index_
protected

The documentation for this class was generated from the following file: