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Re: Speeding up stalled script

by BrowserUk (Patriarch)
on Feb 03, 2015 at 03:52 UTC ( [id://1115335]=note: print w/replies, xml ) Need Help??


in reply to Speeding up stalled script

On initial inspection, I strongly suspect that the problem you describe with larger input file is because of your profligate use of memory pushing your process into swapping and thus slowing it down by a factor of 1,000 times or more.

An example. In this loop:

foreach my $len(@uniques) { push @distrbtn, $len; my $index = 0; my $count = 0; while( $index <= $#sorted ) { if( $len == $sorted[$index] ) { $count++; } $index++; } push @distrbtn, $count; }

You build an array by alternately pushing the length; and then the count of sequences of that length.

And then as soon as the loop finishes you convert that array into a hash:

my %dstrbtn_hash = @distrbtn;

And (AFAI saw), the array is never referenced again, but sticks around using memory for the rest of the script.

Why build the array only to convert it into a hash? Why not just do:

my %dstrbtn_hash; foreach my $len(@uniques) { my $index = 0; my $count = 0; while( $index <= $#sorted ) { if( $len == $sorted[$index] ) { $count++; } $index++; } $dstrbtn_hash{ $len } = $count; }

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
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