edu.rice.hj.api

Interface HjFinishAccumulator

All Known Implementing Classes:

FinishAccumulator

public interface HjFinishAccumulator

Finish accumulators are a construct that support predefined parallel reductions for dynamic task parallelism. Finish accumulators are designed to be integrated into structured task parallelism constructs, such as the async and finish constructs so as to guarantee determinism for accumulation and to avoid any possible race conditions in referring to intermediate results.

Parallel tasks asynchronously transmit their data to finish accumulators with put operations and retrieve the results by get operations. A finish accumulator, ac, is accessible to sub-tasks if and only if ac is associated with a finish statement and the sub-tasks are created within the finish scope. To ensure an absence of races, get operations by sub-tasks return the value at the beginning of the associated finish scope and are not affected by put operations within the same finish scope.

More details: Finish Accumulators: An Efficient Reduction Construct for Dynamic Task Parallelism. Jun Shirako, Vincent Cave, Jisheng Zhao, Vivek Sarkar. The 4th Workshop on Determinism and Correctness in Parallel Programming (WoDet), March 2013.

Author:

Jun Shirako (shirako@rice.edu), Vincent Cave (vincent.cave@rice.edu), Jisheng Zhao (jisheng.zhao@rice.edu), Vivek Sarkar (vsarkar@rice.edu), Shams Imam (shams@rice.edu) [HJ-lib impl]

Method Summary

Modifier and Type	Method and Description
Number	get() Returns the result stored in the accumulator visible to the currently executing task.
HjOperator	getOperator() Returns the operator in use by the accumulator.
Class	getType() Returns the type of result stored by the accumulator.
void	put(double val) Transmits a double value for accumulation to the accumulator.
void	put(int val) Transmits an int value for accumulation to the accumulator.
void	put(Number val) Transmits a Number value for accumulation to the accumulator.

Method Detail

put

void put(Number val)

Transmits a Number value for accumulation to the accumulator.

Parameters:

val - The value to transmit.

put

void put(int val)

Transmits an int value for accumulation to the accumulator.

Parameters:

val - The value to transmit.

put

void put(double val)

Transmits a double value for accumulation to the accumulator.

Parameters:

val - The value to transmit.

get

Number get()

Returns the result stored in the accumulator visible to the currently executing task.

Returns:

the result stored in the accumulator visible to the currently executing task.

getType

Class getType()

Returns the type of result stored by the accumulator.

Returns:

the type of result stored by the accumulator.

getOperator

HjOperator getOperator()

Returns the operator in use by the accumulator.

Returns:

the operator in use by the accumulator.