FW: GMP news

Rev. Chris Korda victimofleisure at gmail.com
Sun Nov 23 06:07:00 CET 2008

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.

Best regards,

Chris Korda

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