Beefy Boxes and Bandwidth Generously Provided by pair Networks
"be consistent"

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??

I had a data file that might as well have been generated this way:

for( my $i = 0; $i < 1_000_000; $i++ ) { print join ' ', map { int rand 256 } 0 .. 50; print "\n"; }

I read my data file this way:

my @d; $#d = 1_000_000; # presize the array! my $i = 0; while (<>) { chomp; $d[$i++] = [ split ]; }

After that, I do a lot of arithmetic with the resulting array. I expected this to take a lot of memory and a long time, but I did not expect my memory usage to increase once the array was populated. Much to my dismay, my program kept growing and growing until I killed it to save its slimmer siblings.

I spent a good hour commenting out parts and printing out pieces before I got around to blaming the arithmetic, and it finally came clear to me. My huge pile of strings (hot off the text file!) was being converted to numbers.

So now my read loop has this in it:

$d[$i++] = [ map { int $_ } split ];

As a result, my program uses a lot less memory, and, more importantly, it does not grow.

In reply to Strings and numbers: losing memory and mind. by kyle

Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?

What's my password?
Create A New User
Domain Nodelet?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others examining the Monastery: (2)
As of 2023-09-24 17:12 GMT
Find Nodes?
    Voting Booth?

    No recent polls found