Threads::BlockedRange

Section: C Library Functions (3) Updated: Thu Apr 7 2011 Local index Up

NAME

Threads::BlockedRange -

SYNOPSIS

#include <threads.h>

Public Types

typedef T const_iterator

Public Member Functions

BlockedRange (const unsigned int grainsize=1000)

BlockedRange (const const_iterator first, const const_iterator last, const unsigned int grainsize=1000)

BlockedRange (const BlockedRange< T > &r)

BlockedRange (BlockedRange< T > &r, Threads::split)

void reset (const const_iterator first, const const_iterator last)

const_iterator begin () const

const_iterator end () const

unsigned int grainsize () const

void grainsize (const unsigned int &gs)

int size () const

bool empty () const

bool is_divisible () const

Private Attributes

const_iterator _end

const_iterator _begin

unsigned int _grainsize

Detailed Description

template<typename T> class Threads::BlockedRange< T >

Blocked range which can be subdivided and executed in parallel.

Definition at line 304 of file threads.h.

Member Typedef Documentation

template<typename T> typedef T Threads::BlockedRange< T >::const_iteratorAllows an StoredRange to behave like an STL container.

Definition at line 310 of file threads.h.

Constructor & Destructor Documentation

template<typename T> Threads::BlockedRange< T >::BlockedRange (const unsigned intgrainsize = 1000) [inline]Constructor. Optionally takes the grainsize parameter, which is the smallest chunk the range may be broken into for parallel execution.

Definition at line 317 of file threads.h.

                                                       :
      _grainsize(grainsize)
    {}

template<typename T> Threads::BlockedRange< T >::BlockedRange (const const_iteratorfirst, const const_iteratorlast, const unsigned intgrainsize = 1000) [inline]Constructor. Takes the beginning and end of the range. Optionally takes the grainsize parameter, which is the smallest chunk the range may be broken into for parallel execution.

Definition at line 327 of file threads.h.

References Threads::BlockedRange< T >::reset().

                                                       :
      _grainsize(grainsize)
    {
      this->reset(first, last);
    }

template<typename T> Threads::BlockedRange< T >::BlockedRange (const BlockedRange< T > &r) [inline]Copy constructor. The StoredRange can be copied into subranges for parallel execution. In this way the initial StoredRange can be thought of as the root of a binary tree. The root element is the only element which interacts with the user. It takes a specified range of objects and packs it into a contiguous vector which can be split efficiently. However, there is no need for the child ranges to contain this vector, so long as the parent outlives the children. So we implement the copy constructor to specifically omit the _objs vector.

Definition at line 348 of file threads.h.

                                           :
      _end(r._end), 
      _begin(r._begin),
      _grainsize(r._grainsize)
    {}

template<typename T> Threads::BlockedRange< T >::BlockedRange (BlockedRange< T > &r, Threads::split) [inline]Splits the range r. The first half of the range is left in place, the second half of the range is placed in *this.

Definition at line 359 of file threads.h.

References Threads::BlockedRange< T >::_begin, and Threads::BlockedRange< T >::_end.

                                                     : 
      _end(r._end),
      _begin(r._begin),
      _grainsize(r._grainsize)
    {
      const_iterator
        beginning = r._begin,
        ending    = r._end,
        middle    = beginning + (ending - beginning)/2u;
    
      r._end = _begin = middle;
    }

Member Function Documentation

template<typename T> const_iterator Threads::BlockedRange< T >::begin () const [inline]Beginning of the range.

Definition at line 385 of file threads.h.

References Threads::BlockedRange< T >::_begin.

{ return _begin; }

template<typename T> bool Threads::BlockedRange< T >::empty () const [inline]Returns true if the range is empty.

Definition at line 415 of file threads.h.

References Threads::BlockedRange< T >::_begin, and Threads::BlockedRange< T >::_end.

{ return (_begin == _end); }

template<typename T> const_iterator Threads::BlockedRange< T >::end () const [inline]End of the range.

Definition at line 390 of file threads.h.

References Threads::BlockedRange< T >::_end.

{ return _end; }

template<typename T> unsigned int Threads::BlockedRange< T >::grainsize () const [inline]The grain size for the range. The range will be subdivided into subranges not to exceed the grain size.

Definition at line 396 of file threads.h.

References Threads::BlockedRange< T >::_grainsize.

Referenced by Threads::BlockedRange< T >::is_divisible().

{return _grainsize;}

template<typename T> void Threads::BlockedRange< T >::grainsize (const unsigned int &gs) [inline]Set the grain size.

Definition at line 401 of file threads.h.

References Threads::BlockedRange< T >::_grainsize.

{_grainsize = gs;}

template<typename T> bool Threads::BlockedRange< T >::is_divisible () const [inline]Returns true if the range can be subdivided.

Definition at line 420 of file threads.h.

References Threads::BlockedRange< T >::_begin, Threads::BlockedRange< T >::_end, and Threads::BlockedRange< T >::grainsize().

{ return ((_begin + this->grainsize()) < _end); }

template<typename T> void Threads::BlockedRange< T >::reset (const const_iteratorfirst, const const_iteratorlast) [inline]Resets the StoredRange to contain [first,last).

Definition at line 375 of file threads.h.

References Threads::BlockedRange< T >::_begin, and Threads::BlockedRange< T >::_end.

Referenced by Threads::BlockedRange< T >::BlockedRange().

    {
      _begin = first;
      _end   = last;
    }

template<typename T> int Threads::BlockedRange< T >::size () const [inline]Returns:

: the size of the range.

Definition at line 406 of file threads.h.

References Threads::BlockedRange< T >::_begin, and Threads::BlockedRange< T >::_end.

{ return (_end -_begin); }

Member Data Documentation

template<typename T> const_iterator Threads::BlockedRange< T >::_begin [private]

Definition at line 425 of file threads.h.

Referenced by Threads::BlockedRange< T >::begin(), Threads::BlockedRange< T >::BlockedRange(), Threads::BlockedRange< T >::empty(), Threads::BlockedRange< T >::is_divisible(), Threads::BlockedRange< T >::reset(), and Threads::BlockedRange< T >::size().

template<typename T> const_iterator Threads::BlockedRange< T >::_end [private]

Definition at line 424 of file threads.h.

Referenced by Threads::BlockedRange< T >::BlockedRange(), Threads::BlockedRange< T >::empty(), Threads::BlockedRange< T >::end(), Threads::BlockedRange< T >::is_divisible(), Threads::BlockedRange< T >::reset(), and Threads::BlockedRange< T >::size().