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I came across a wonderful site, by Jason Brownlee, demonstrating Barriers using Python. That's what I want for MCE::Barrier to accomplish. Hold on... I'm not finished yet. The MCE::Barrier, MCE::Semaphore, and MCE::Simple modules will be released once completing the documentation and test scripts.

The barrier wait method supports two modes; list-context or exception-raised (if aborted or timed out). Notice also, the spawn keyword being used in a loop. That works too :)

Barrier with a Timeout

# Perl replica of using a Barrier with a Timeout
# https://superfastpython.com/multiprocessing-barrier-in-python/

use MCE::Simple -strict, -signatures;
use MCE::Barrier;
use Time::HiRes 'sleep';
use Try::Tiny;

STDOUT->autoflush(1);

sub task ($barrier, $number) {
    # generate a unique value and block for a moment
    my $value = rand() * 10; sleep($value);

    # report result
    say "Process ${number} done, got: ${value}";

    # wait on all other processes to complete
    # my ($remaining, $error) = $barrier->wait;
    # or via exception handling
    try {
        $barrier->wait;
    }
    catch {
        # pass
    };
}

sub main () {
    # create a barrier plus one for the main process
    my $barrier = MCE::Barrier->new(5 + 1);

    # create the worker processes
    spawn task($barrier, $_) for 1..5;

    # wait for all processes to finish
    # my ($remaining, $error) = $barrier->wait;
    # or via exception handling
    try {
        $barrier->wait(timeout => 5);
        say "All processes have their result";
    }
    catch {
        # $_ = "Operation timed out ..."
        say "Some processes did not finish on time...";
    };

    # reap the worker processes
    sync;
}

main();

__END__
Process 2 done, got: 2.20488202831806
Process 1 done, got: 4.51354761681618
Some processes did not finish on time...
Process 5 done, got: 5.27888526282371
Process 4 done, got: 7.58755085132183
Process 3 done, got: 9.89621643981994
[download]

Barrier with an Action

# Perl replica of using a Barrier with an Action
# https://superfastpython.com/multiprocessing-barrier-in-python/

use MCE::Simple -strict, -signatures;
use MCE::Barrier;
use Time::HiRes 'sleep';

STDOUT->autoflush(1);

sub report () {
    # report once all processes are done
    say "All processes have their result";
}

sub task ($barrier, $number) {
    # generate a unique value and block for a moment
    my $value = rand() * 10; sleep($value);

    # report result
    say "Process ${number} done, got: ${value}";

    # wait on all other processes to complete
    my ($remaining, $error) = $barrier->wait;

    # an alternative to using the "action" argument
    if ($remaining == 0) {
        say "I, process ${number}, was last...";
    }
}

sub main () {
    # create a barrier, not including the main process
    my $barrier = MCE::Barrier->new(5, before_release => \&report);

    # create the worker processes
    spawn task($barrier, $_) for 1..5;

    # reap the worker processes
    sync;
}

main();

__END__
Process 1 done, got: 1.25912054515542
Process 5 done, got: 2.02445819116296
Process 4 done, got: 4.33312377966107
Process 3 done, got: 6.64178936815919
Process 2 done, got: 8.9504549566573
All processes have their result
I, process 2, was last...
[download]

Aborting a Barrier

# Perl replica of Aborting a Barrier
# https://superfastpython.com/multiprocessing-barrier-in-python/

use MCE::Simple -strict, -signatures;
use MCE::Barrier;
use Time::HiRes 'sleep';
use Try::Tiny;

STDOUT->autoflush(1);

sub task ($barrier, $number) {
    # generate a unique value and block for a moment
    my $value = rand() * 10; sleep($value);

    # report result
    say "Process ${number} done, got: ${value}";

    # check if the result was "bad"
    if ($value > 8) {
        say "Process ${number} aborting...";
        $barrier->abort;
    }
    else {
        # wait on all other processes to complete
        # my ($remaining, $error) = $barrier->wait;
        # or via exception handling
        try {
            $barrier->wait;
        }
        catch {
            # pass
        };
    }
}

sub main () {
    # create a barrier plus one for the main process
    my $barrier = MCE::Barrier->new(5 + 1);

    # create the worker processes
    spawn task($barrier, $_) for 1..5;

    # wait for all processes to finish
    # my ($remaining, $error) = $barrier->wait;
    # or via exception handling
    try {
        $barrier->wait();
        say "All processes have their result";
    }
    catch {
        # $_ = "Barrier aborted ..."
        say "At least one process aborted due to bad results";
    };

    # reap the worker processes
    sync;
}

main();

__END__
Process 1 done, got: 1.12563261603103
Process 5 done, got: 1.89097026203857
Process 4 done, got: 4.19963585053669
Process 3 done, got: 6.5083014390348
Process 2 done, got: 8.81696702753292
Process 2 aborting...
At least one process aborted due to bad results
[download]

In reply to Re: Code brewing for the upcoming MCE 10 year anniversary by marioroy
in thread Code brewing for the upcoming MCE 10 year anniversary by marioroy

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