[Fwd: [OctDev] slow structs]

[Daniel J Sebald]

-------- Original Message --------
Subject: [OctDev] slow structs
Date: Wed, 17 Dec 2008 18:13:17 -0600
From: Jonathan Kotta <jpkotta at gmail.com>
To: octave-dev at lists.sourceforge.net

I have a problem where a vector within a struct is much slower to
index than a plain vector (~8x slower) .

x = zeros(1e6,1);
s.x = x;
subset = 500e3:600e3-1;
y = randn(length(subset),1);
for i = 1:5
   tic; x(subset) = y; toc;
end
for i = 1:5
   tic; s.x(subset) = y; toc;
end
tic;
for i = 1:100
   x(subset) = y;
end
toc;
tic;
for i = 1:100
   s.x(subset) = y;
end
toc;

Tested using Octave 3.0.3 on x86-64.

-- 
Thanks,

Jonathan Kotta

Hofstadter's Law:
    It always takes longer than you expect, even
    when you take into account Hofstadter's Law.

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-- 

Dan Sebald
email: daniel(DOT)sebald(AT)ieee(DOT)org
URL: http://www(DOT)dansebald(DOT)com