/ 
MCE-Shared-1.879
River stage one • 2 direct dependents • 3 total dependents
/ MCE::Shared::Sequence

NAME

MCE::Shared::Sequence - Sequence helper class

VERSION

This document describes MCE::Shared::Sequence version 1.879

DESCRIPTION

A number sequence class for use as a standalone or managed by MCE::Shared.

SYNOPSIS

# non-shared or local construction for use by a single process

use MCE::Shared::Sequence;

my $seq_a = MCE::Shared::Sequence->new( $begin, $end, $step, $fmt );

my $seq_b = MCE::Shared::Sequence->new(
   { chunk_size => 10, bounds_only => 1 },
   $begin, $end, $step, $fmt
);

# construction for sharing with other threads and processes

use MCE::Shared;

my $seq_a = MCE::Shared->sequence( 1, 100 );

my $seq_b = MCE::Shared->sequence(
   { chunk_size => 10, bounds_only => 1 },
   1, 100
);

# example

use MCE::Hobo;

sub parallel_a {
   my ( $id ) = @_;
   while ( defined ( my $num = $seq_a->next ) ) {
      print "$id: $num\n";
   }
}

sub parallel_b {
   my ( $id ) = @_;
   while ( my ( $beg, $end ) = $seq_b->next ) {
      for my $num ( $beg .. $end ) {
         print "$id: $num\n";
      }
   }
}

MCE::Hobo->new( \&parallel_a, $_ ) for 1 .. 2;
MCE::Hobo->new( \&parallel_b, $_ ) for 3 .. 4;

# ... do other work ...

MCE::Hobo->waitall();

API DOCUMENTATION

MCE::Shared::Sequence->new ( { options }, begin, end [, step, format ] )

MCE::Shared::Sequence->new ( begin, end [, step, format ] )

MCE::Shared->sequence ( { options }, begin, end [, step, format ] )

MCE::Shared->sequence ( begin, end [, step, format ] )

Constructs a new object. step, if omitted, defaults to 1 if begin is smaller than end or -1 if begin is greater than end. The format string is passed to sprintf behind the scene (% may be omitted).

$seq_n_formatted = sprintf( "%4.1f", $seq_n );

Two options chunk_size and bounds_only are supported, which default to 1 and 0 respectively. Chunking reduces the number of IPC calls to and from the shared-manager process for large sequences.

If bounds_only => 1 is specified, the next method computes the begin and end values only for the chunk and not the numbers in between (hence boundaries only).

use MCE::Shared;

# demo 1

$seq1 = MCE::Shared->sequence(
   { chunk_size => 10, bounds_only => 0 }, 1, 20
);

# @chunk = $seq1->next;  # ( qw/  1  2  3  4  5  6  7  8  9 10 / )
# @chunk = $seq1->next;  # ( qw/ 11 12 13 14 15 16 17 18 19 20 / )

while ( my @chunk = $seq1->next ) {
   ...
}

# demo 2

$seq2 = MCE::Shared->sequence(
   { chunk_size => 10, bounds_only => 1 }, 1, 100
);

# ( $beg, $end ) = $seq2->next;  # (  1,  10 )
# ( $beg, $end ) = $seq2->next;  # ( 11,  20 )
# ( $beg, $end ) = $seq2->next;  # ( 21,  30 )
#    ...
# ( $beg, $end ) = $seq2->next;  # ( 81,  90 )
# ( $beg, $end ) = $seq2->next;  # ( 91, 100 )

# The optional chunk_id value, starting at 1, applies to sequence
# objects configured with the bounds_only option set to a true
# value. API available since 1.834.

while ( my ( $beg, $end, $chunk_id ) = $seq2->next ) {
   for my $i ( $beg .. $end ) {
      ...
   }
}

Parameters may be given later with rewind before calling next.

# non-shared or local construction for use by a single process

use MCE::Shared::Sequence;

$seq = MCE::Shared::Sequence->new;
$seq->rewind( -1, 1, 0.1, "%4.1f" );

$seq = MCE::Shared::Sequence->new(
   { chunk_size => 10, bounds_only => 1 }, 1, 100
);

# construction for sharing with other threads and processes

use MCE::Shared;

$seq = MCE::Shared->sequence;
$seq->rewind( 1, 100 );

$seq = MCE::Shared->sequence(
   { chunk_size => 10, bounds_only => 1 }, 1, 100
);

next

Returns the next computed sequence(s). An undefined value is returned when the computed begin value exceeds the value held by end.

# default: { chunk_size => 1, bounds_only => 0 }
$seq = MCE::Shared->sequence( 1, 100 );

while ( defined ( my $num = $seq->next ) ) {
   ...
}

# chunking

$seq = MCE::Shared->sequence(
   { chunk_size => 10 }, 1, 100
);

while ( my @chunk = $seq->next ) {
   ...
}

# chunking, boundaries only

$seq = MCE::Shared->sequence(
   { chunk_size => 10, bounds_only => 1 }, 1, 100
);

while ( my ( $beg, $end, $chunk_id ) = $seq->next ) {
   for my $i ( $beg .. $end ) {
      ...
   }
}

rewind ( { options }, begin, end [, step, format ] )

rewind ( begin, end [, step, format ] )

Sets the initial value back to the value held by begin when no arguments are given. Otherwise, resets the sequence with given criteria.

$seq->rewind;

$seq->rewind( { chunk_size => 10, bounds_only => 1 }, 1, 100 );

while ( my ( $beg, $end ) = $seq->next ) {
   for my $i ( $beg .. $end ) {
      ...
   }
}

$seq->rewind( 1, 100 );

while ( defined ( my $num = $seq->next ) ) {
   ...
}

INDEX

MCE, MCE::Hobo, MCE::Shared

AUTHOR

Mario E. Roy, <marioeroy AT gmail DOT com>