That's stupid. ...

Hmm, perhaps. The way I was looking at it is that its a * k / b * k (which im not arguing is correct, as i dont know, merely explaining :-). Where if the k=1 when using eval and k=1.1 using a subref the ratio stays the same. Maybe this isnt the correct analysis, if so please enlighten me, but please without the "stupid" bit, im well well aware of my own limitations. :-)

If the ratios of two algorithms would vary wildly from machine to machine...

I have to admit that I assumed you meant the rate per second. Now that I see what you mean I concede my point is not correct.

Right figure, wrong conclusion. The slowdown isn't mainly caused by the use of $&, but the copying involved.

Wow. You are sooo right. If you look closely at my redo of theorbtwos code and the code in bm_theorbtwo.pl the assignment that is present is responsible for the difference. When I made sure that the combined version and the seperate version were _exactly_ the same the results were comparable. Thanks. And good point.

the costs of $& and more so from $` and $' come if you are using other regural expression in your program, for which you don't use $& and friends. But that's not what you are benchmarking.

Actually that was what I was trying to get at, if in a somewhat oblique way. :-). Anyway, it looks to me that the presence of $& doesnt in the end have much effect on the validity of the benchmark. Which is cool and interesting. Thanks Abigail-II.

BTW, i assume 

my $opts='-5 \\\\\\\\foo\\\\bar\\\\baz.exe';

[download]
is because your shell is converting \\ to \?

Yves / DeMerphq
---
Software Engineering is Programming when you can't. -- E. W. Dijkstra (RIP)

In reply to Re: Re: Unfortunately benchmarking things with $& isn't easy... by demerphq
in thread Obtaining server name from UNC path by blackadder

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


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.