Fork–join model

<p>In <a href="/facts/Parallel_computing/nQzcpzQt">parallel computing</a>, the fork–join model is a way of setting up and executing parallel programs, such that execution branches off in parallel at designated points in the program, to "join" (merge) at a subsequent point and resume sequential execution. Parallel sections may fork <a href="/facts/Recursion_(computer_science)/2uXo18Gv">recursively</a> until a certain task granularity is reached.  Fork–join can be considered a parallel <a href="/facts/Design_pattern/bHvkoxsu">design pattern</a>.: 209 ff.  It was formulated as early as 1963.
</p><p>By nesting fork–join computations recursively, one obtains a parallel version of the <a href="/facts/Divide_and_conquer_algorithms/pC1X7Ws7">divide and conquer</a> paradigm, expressed by the following generic <a href="/facts/Pseudocode/XgN19duK">pseudocode</a>:
</p>
solve(problem):
    if problem is small enough:
        solve problem directly (sequential algorithm)
    else:
        for part in subdivide(problem)
            fork subtask to solve(part)
        join all subtasks spawned in previous loop
        return combined results

Fork–join model open-in-new

Fork–join model