context Class Template Reference

CnC context bringing together collections and steps and specifies the prescription relationship. More...

List of all members.

Public Member Functions
	context ()
	default constructor
virtual	~context ()
	destructor
template<typename TagColl, typename Step, typename Tuner, typename Arg>
error_type	prescribe (TagColl &tc, const Step &step, const Tuner &tuner, Arg &arg)
	Convenient was to declare the prescription relationship between a tag collection and a step collection.
error_type	wait ()
	wait until all the steps prescribed by this context have completed execution.
void	flush_gets ()
	used with the preschedule tuner to finalize 'gets' in the pre-execution of a step
void	reset ()
	reset all collections of this context
template<class Index, class Functor>
Functor	parallel_for (Index first, Index last, Index step, const Functor &f, bool gets_items=true)
	Execute f( i ) for every i in {first <= i=first+step*x < last and 0 <= x}.
template<class Index, class Functor, class Tuner>
Functor	parallel_for (Index first, Index last, Index step, const Functor &f, const Tuner &tuner)
	Execute f( i ) for every i in {first <= i=first+step*x < last and 0 <= x}.

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Detailed Description

template<class Derived>
class CnC::context< Derived >

CnC context bringing together collections and steps and specifies the prescription relationship.

The user needs to derive his or her own context from the CnC::context. The template argument to context is the user's context class itself.

For example,

   struct my_context : public CnC::context< my_context >
   {
      CnC::tag_collection<int> oddNums;
      CnC::item_collection<int,int> primes;
      my_context() 
          : CnC::context< my_context >(),
            oddNums( this ),
            primes( this )
      {
          prescribe( oddNums, FindPrimes() );
      }
   };

Several contexts can be created and executed simultaneously.

Execution starts as soon as a step is prescribed. All ready steps will be executed even if CnC::context::wait() is never be called.

It is recommended to declare collections as members of a context derived from CnC::context. This yields more maintanable code and future versions of CnC may require this convention.

Definition at line 267 of file cnc.h.

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Member Function Documentation

error_type prescribe	(	TagColl &	tc,
		const Step &	step,
		const Tuner &	tuner,
		Arg &	arg
	)			[inline]

Convenient was to declare the prescription relationship between a tag collection and a step collection.

See also:

tag_collection::prescribe

Parameters:

	step	class/object representing step collection.
	tuner	is optional. By default this argument is CnC:default_tuner.
	arg	is optional. By default this argument is the derived context class.

Returns:

0 if succeeded, error code otherwise

error_type wait

(

)

wait until all the steps prescribed by this context have completed execution.

Returns:

0 if succeeded, error code otherwise

void flush_gets

(

)

used with the preschedule tuner to finalize 'gets' in the pre-execution of a step

Call this after last call to the non-blocking item_collection::unsafe_get method.

Functor parallel_for	(	Index	first,
		Index	last,
		Index	step,
		const Functor &	f,
		bool	gets_items = true
	)			[inline]

Execute f( i ) for every i in {first <= i=first+step*x < last and 0 <= x}.

For different values of i, function execution might occur in parallel. Returns functor object ocne all iterations have been executed. Type Index must support operator+. It uses the tuner default_tuner< Index, derived >

Parameters:

	first	starting index of parallel iteration
	last	iteration stops before reaching last
	step	iteration step: increase ireation index by step in each iteration
	f	function to be executed
	gets_items	true (default) if function gets items, false otherwise (might perform better)

Functor parallel_for	(	Index	first,
		Index	last,
		Index	step,
		const Functor &	f,
		const Tuner &	tuner
	)			[inline]

Execute f( i ) for every i in {first <= i=first+step*x < last and 0 <= x}.

For different values of i, function execution might occur in parallel. Returns functor object ocne all iterations have been executed. Type Index must support operator+.

Parameters:

	first	starting index of parallel iteration
	last	iteration stops before reaching last
	step	iteration step: increase ireation index by step in each iteration
	f	function to be executed
	tuner	tuner, must accept Index as tag and derived as Arg

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

• cnc.h