..  pmap(f, lsts...; err_retry=true, err_stop=false, pids=workers())

Transform collections ``lsts`` by applying ``f`` to each element in parallel.
(Note that ``f`` must be made available to all worker processes; see :ref:`Code Availability and Loading Packages <man-parallel-computing-code-availability>` for details.)
If ``nprocs() > 1``, the calling process will be dedicated to assigning tasks.
All other available processes will be used as parallel workers, or on the processes specified by ``pids``.

If ``err_retry`` is ``true``, it retries a failed application of ``f`` on a different worker.
If ``err_stop`` is ``true``, it takes precedence over the value of ``err_retry`` and ``pmap`` stops execution on the first error.


The pmap function in Julia allows you to apply a given function f to each element of one or more collections lsts in parallel. Here are some examples and explanations of its usage:

  1. Parallel map on a single collection:

    julia> pmap(x -> x^2, [1, 2, 3, 4, 5])
    5-element Array{Int64,1}:

    In this example, the function x -> x^2 is applied to each element of the collection [1, 2, 3, 4, 5] in parallel, resulting in a new collection with the squared values.

  2. Parallel map on multiple collections:

    julia> pmap(+, [1, 2, 3], [4, 5, 6])
    3-element Array{Int64,1}:

    Here, the + function is applied to the corresponding elements of the two collections [1, 2, 3] and [4, 5, 6] in parallel. The result is a new collection with the element-wise sum.

  3. Using custom functions:
    julia> function myfunc(x)
              return x^2 + 2x + 1
    julia> pmap(myfunc, [1, 2, 3, 4, 5])
    5-element Array{Int64,1}:

    In this example, a custom function myfunc is defined and applied to each element of the collection [1, 2, 3, 4, 5] in parallel.

Additional options:

  • err_retry=true: If a worker process fails while applying the function f, the failed application is retried on a different worker.
  • err_stop=false: By default, pmap continues execution on all elements even if an error occurs. Setting err_stop=true stops execution on the first error and returns the results obtained so far.

Please note that the function f must be available to all worker processes. Refer to Julia's documentation on "Code Availability and Loading Packages" for more details.

See Also

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