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Subject: Re: [boost] different matrix library?
From: DE (satan66613_at_[hidden])
Date: 2009-08-18 12:00:03


on 18.08.2009 at 18:59
 joel wrote :

> DE wrote:
>> looks smart and tricky but i don't see any advantages over computed
>> indeces but only wasted spaces and time (for allocating additional
>> storage for pointers)
>> at the same time dereferencing a pointer is like computing an index -
>> no computational advantage agai
> Back to this issue here is the generated code using
> 1/ NRC array of dimension 4
> [code here]
> Lo and behold ;)
> Doing the computation of index jump int he allcoation helps tremendously.
fewer instructions doesn't mean faster code
to find ideal ratio you must take intel arch manual and count the clocks
or you can actually measure running time for a variety of cases

i naively (lack of time) implemented nrc (how it is spelled btw?) for
2d case and it performs worse then computed indeces in general
i'll try to reimplement it properly and measure again

-- 
Pavel

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