From: Eleanor McHugh <eleanor@...>
Date: 2008-06-27T20:59:12+09:00
Subject: Re: Performance improvement possible?

On 27 Jun 2008, at 12:41, Robert Klemme wrote:
> 2008/6/27 Eleanor McHugh <eleanor@games-with-brains.com>:
>> I'm surprised at the behaviour you're seeing so I ran a quick  
>> benchmark on
>> what I believe to be an equivalent array handling problem with my  
>> laptop (OS
>> X, Ruby 1.8.6-p111, Core 2 Duo 2GHz, 2GB RAM):
>>
>> require 'benchmark'
>> include Benchmark
>> bm(6) do |y|
>>  y.report("appending") { x = []; (1..20000000).each { |i| x << i } }
>>  y.report("nested creation") { x = Array.new(1000)  
>> { Array.new(1000) {
>> Array.new(20, 0) } } }
>>  y.report("unrolling") { x.flatten.flatten.length }
>> end
>
> This can't be the exact code you were benchmarking since "x" is
> undefined in the "unrolling" test.

I was using IRB and x was already defined earlier in my session, so  
yes and no: for my session it was defined, but for this snippet it  
won't be.

> Also, why do you flatten twice?
> You can't beat an Array flatter than flatten. :-)

I was posting at 2am >;o


Ellie

Eleanor McHugh
Games With Brains
http://slides.games-with-brains.net
----
raise ArgumentError unless @reality.responds_to? :reason