NAME

MCE::Shared::Sequence - Sequence helper class

VERSION

This document describes MCE::Shared::Sequence version 1.811

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

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

new ( 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 )

   while ( my ( $beg, $end ) = $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 ) = $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>