large-scale polynomial gcd calculations



Andrey G. Grozin wrote:
> Hello *,
> 
....
> 
> I have several questions to the gurus:
> 
> 1. How to disable the history mechanism which assigns stuff to %i and 
> %o ? No linear decrease of available memory is tolerable.

set nolabels:true$
> 
> 2. Which gcd algorithm to use? Some of them contain bugs.

Probably they don't have bugs. I suspect the programs that call them have
bugs in the way they are set up. If you have exactly rational functions
of simple variables, I think they all work.
If there are bugs in such circumstances, I am not aware of them.
(In particular, such reported bugs usually accuse subres of having
a bug. Since it is about 15 lines of code, that seems implausible.)

The best gcd algorithm depends on the nature of the input. Dense?
Many variables? Large GCD or probably GCD=1? Large coefficients?

Two suggestions: EEZGCD if sparse. Perhaps SUBRES, if the GCD is large.


The inputs should be immediately converted to rat() form, and never stored
in the usual top-level format.  They probably should not be printed by
any of the front-ends, which may run out of memory.


> 
> 3. The platforms which will be used are: Pentium-4, AMD Opteron, 
> Itanium2 (32-processor SGI Altix server), SUSE Linux everywhere. What 
> lisps can run on all of them? What about 64-bit addressing - possible? 
> desirable?
> 
> 4. Are there upper limits on the memory which maxima on each of these 
> lisps can use? How to increase them?
> 
> Best regards,
> Andrey
> 
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