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Re: speed of octave interpreter


From: David Bateman
Subject: Re: speed of octave interpreter
Date: Thu, 29 Sep 2005 09:56:01 +0200
User-agent: Mozilla Thunderbird 0.8 (X11/20040923)

Brendan Drew wrote:

The STL uses a hybrid of quicksort and heapsort (introspectsort I believe it's called) which works by using quicksort until the stack depth reaches some predetermined threshold. At this point, it switches to heapsort to solve that subproblem. Results are what you'd expect for a quicksort with guaranteed O(n lg n) run time. SGI's numbers placed it roughly neck-and-neck with qsort on non-pathological inputs (i.e. roughly twice as fast as heapsort), but significantly better than heapsort on pathological inputs. Maybe this is worth investigating?

~B

Brendan,

I'm sorry this is a case where I'll have to say "show me the code"... I spent a large amount of time on sort and got about a factor of 5 speed up. The most I'd expected you could get as an improve now is 70% (the difference in the worst case with matlab) and so I personally don't want to spend the effort improving it further. Of course if you come up with something better, I'd be happy to see my code thrown out in favour of yours...

Cheers
David

--
David Bateman                                address@hidden
Motorola Labs - Paris +33 1 69 35 48 04 (Ph) Parc Les Algorithmes, Commune de St Aubin +33 1 69 35 77 01 (Fax) 91193 Gif-Sur-Yvette FRANCE

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