Speeding up unshift may explain what is going on.
Through Perl 5.6.1, unshift left the array aligned on the left. So if you build up an array with unshift's it is forced to realign it on every single unshift. If you build an array with repeated unshifts this makes the cost of each linear, for quadratic total time. What tilly's patch does is realign it indented to the length of the current array. So you only realign after you unshift the length of the array elements. In the simple case of adding one element at a time, this boils down to realigning at powers of 2, for a constant amortized cost.
The code could be more efficient, but there don't seem to be order of magnitude algorithmic improvements left.
-
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.
|