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Too much of a good thing?
Sergei Egorov
(10 Apr 2003 07:20 UTC)
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Re: Too much of a good thing?
Per Bothner
(11 Apr 2003 05:54 UTC)
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AW: Too much of a good thing?
Michael Burschik
(11 Apr 2003 07:35 UTC)
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Re: AW: Too much of a good thing?
Per Bothner
(11 Apr 2003 15:18 UTC)
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AW: AW: Too much of a good thing?
Michael Burschik
(14 Apr 2003 08:32 UTC)
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Re: Too much of a good thing? David Rush (23 Apr 2003 09:21 UTC)
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Re: Too much of a good thing?
Taylor Campbell
(15 Apr 2003 02:16 UTC)
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Re: Too much of a good thing? David Rush 23 Apr 2003 09:17 UTC
Per Bothner <xxxxxx@bothner.com> writes: > Sergei Egorov wrote: > > <Flame> > > I think that most of the operations that generate vectors element-by-element > > are useless, especially when the performance is the same as in making a list > > first and then turning it into a vector. > > - which of course is never. Yeah, you can easily do it *more expensively*. ISTM that a resizing+copying implementation, while it may win on cache locality for small vectors, loses on big vectors. First you've got the problem of doubling the allocation of your million element array when you're only going to *need* 1100000 elements. Secondly, it's not entirely clear to me that the cache locality improvement will compensate for the log2(n)^2 element copies you'll be making along the way. IMO, the only reasonable vector constructors require a priori knowledge of the vector size. I still like and use resizable vectors (my personal library calls them 'dynamic vectors'), but I'm intentionally making a space/time tradeof when I use them, and the time profile is *not* the same as R5RS vectors although they are still constant-time access. david rush -- And Visual Basic programmers should be paid minimum wage :) -- Jeffrey Straszheim (on comp.lang.functional)