JROMP (Java Runtime OpenMP)

JROMP is a Java library that provides a simple API for parallel programming using OpenMP-like constructs, but in runtime. It is designed to provide a simple way to parallelize Java code. JROMP is implemented using Java's ThreadPoolExecutor and designed to be efficient and scalable.

Features

• Simple API for parallel programming.
• Efficient and scalable implementation using ThreadPoolExecutor.
• Compatible with Java 21 and later.
• Minimal dependencies.
• Easy to use.

Supported constructs

• parallel - Executes a block of code in parallel.
• for - Executes a loop in parallel.
• sections - Executes a block of code in parallel.
• single - Executes a block of code in a single thread.
• barrier - Synchronizes all threads.
• critical - Executes a block of code in a critical section.
• atomic - Executes a block of code atomically.
• reduction - Performs a reduction operation.
• masked - Executes a block of code in the specified thread.

Supported variables

• shared - Shared variable between threads.
• private - Private variable for each thread.
• firstprivate - Private variable with initial value (it takes the value prior to the parallel region).
• lastprivate - Last private variable (it takes the value after the parallel region).
• reduction - Reduction variable (it accumulates the value of each thread depending on the operation).
• atomic - Atomic variable (it is updated atomically).

Installation

To use JROMP in your project, you can add the dependency using the following code snippets:

Maven

<dependency>
  <groupId>io.github.java-romp</groupId>
  <artifactId>jromp</artifactId>
  <version>2.2.0</version>
</dependency>

Gradle

implementation 'io.github.java-romp:jromp:2.2.0'

If your package manager is not listed here, you can check the latest version on the Maven Central Repository.

Usage

Here is an example of how to use JROMP to execute a simple parallel task in all available threads:

import jromp.JROMP;

import static jromp.JROMP.getNumThreads;
import static jromp.JROMP.getThreadNum;

public class BasicUsage {
  public static void main(String[] args) {
    JROMP.allThreads()
         .parallel(variables -> System.out.printf("Hello World from thread %d of %d%n", getThreadNum(), getNumThreads()))
         .join();
  }
}

This code will print Hello World from thread X of Y for each thread, where X is the thread ID and Y is the total number of threads.

More examples

If you want to see more examples of how to use JROMP, you can check all the available examples (with its equivalent code written in C) in the jromp-examples repository.