GMP news

Brian Gladman brg at
Sun Nov 23 12:44:47 CET 2008

----- Original Message ----- 
From: "Rev. Chris Korda" <victimofleisure at>
To: <gmp-discuss at>
Sent: Sunday, November 23, 2008 5:07 AM
Subject: FW: GMP news

> I'm doing time-escape fractals, and I'm finding that e.g. with 768 bits of
> precision, the calculations are painfully slow; approximately three orders
> of magnitude slower than equivalent calculations done with 64-bit FPU or
> SSE. Obviously this isn't a fair comparison, but still I'd like to shorten
> my deep zoom render times by at least an order of magnitude. I'm running 
> on
> a distributed network of Pentium Core 2 processors, using GMP 4.1 with 
> Brian
> Gladman's Pentium4 assembler support.
> Is it possible that I might get improved performance by writing extended
> precision routines in SSE? This would be a third option between hardware
> 64-bit (useless for deep zooms but very fast) and GMP (unlimited zoom but
> brutal render times). The proposed routines would have a fixed precision
> that's a multiple of the machine's word size, e.g. 768 bits. I only need 
> to
> support a small number of operations--two actually, square and add--and 
> the
> square only has to operate on numbers between zero and one, which makes
> things much easier.

That is quite a bit of work so it might be sensible to try GMP 4.2.4 before 
you do this since it might give you a worthwhile speed improvement.

GMP 4.2.4 is available on Windows with assembler support for Intel core 2 
processors operating in both 32 and 64-bit mode. Let me know if you need any 
help with this.

   Brian Gladman

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