dash::SharedCounter< ValueType > Class Template Reference

A simple shared counter that allows atomic increment- and decrement operations. More...

#include <SharedCounter.h>

Public Member Functions
	SharedCounter ()
	Constructor. More...
	SharedCounter (dash::Team &team)
void	inc (ValueType increment)
	Increment the shared counter value, atomic operation. More...
void	dec (ValueType increment)
	Decrement the shared counter value, atomic operation. More...
ValueType	get () const
	Read the current value of the shared counter. More...

Detailed Description

template<typename ValueType = int>
class dash::SharedCounter< ValueType >

A simple shared counter that allows atomic increment- and decrement operations.

TODO: Should probably be based on MPI_ACCUMULATE.

Definition at line 15 of file SharedCounter.h.

Constructor & Destructor Documentation

SharedCounter()

template<typename ValueType = int>

dash::SharedCounter< ValueType >::SharedCounter ( )

inline

Constructor.

Definition at line 23 of file SharedCounter.h.

References dash::Array< ElementType, IndexType, PatternType, LocalMemSpaceT >::barrier(), dash::Array< ElementType, IndexType, PatternType, LocalMemSpaceT >::local, and dash::Team::size().

  : _num_units(dash::Team::All().size()),
    _myid(dash::Team::All().myid()),
    _local_counts(_num_units)
  {
    _local_counts.local[0] = 0;
    _local_counts.barrier();
  }

Member Function Documentation

dec()

template<typename ValueType = int>

void dash::SharedCounter< ValueType >::dec ( ValueType  increment )

inline

Decrement the shared counter value, atomic operation.

Parameters

increment

Decrement value

Definition at line 54 of file SharedCounter.h.

  {
    _local_counts[_myid] -= increment;
  }

get()

template<typename ValueType = int>

ValueType dash::SharedCounter< ValueType >::get ( ) const

inline

Read the current value of the shared counter.

Accumulates increment/decrement values of every unit. Reading a shared is not atomic, use Team::barrier() to synchronize.

Time complexity

O(u) for u units in the associated team

Definition at line 68 of file SharedCounter.h.

References dash::Array< ElementType, IndexType, PatternType, LocalMemSpaceT >::local, and dash::ValueType.

  {
    ValueType acc = 0;
    for (team_unit_t i{0}; i < _num_units; ++i) {
      // use local access on own counter value:
      acc += (i == _myid
                ? _local_counts.local[0]
                : _local_counts[i]);
    }
    return acc;
  }

inc()

template<typename ValueType = int>

void dash::SharedCounter< ValueType >::inc ( ValueType  increment )

inline

Increment the shared counter value, atomic operation.

Parameters

increment

Increment value

Definition at line 44 of file SharedCounter.h.

  {
    _local_counts[_myid] += increment;
  }

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

• /tmp/tmporruphar/dash/include/dash/SharedCounter.h