|Bill Allombert on Thu, 26 Jun 2003 19:52:59 +0200|
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|Re: record size computation|
On Thu, Jun 26, 2003 at 01:33:15PM -0400, Igor Schein wrote: > Hi, > > I have computed galoisinit(P324), where P324 is a degree-324 > polynomial, using a 64bit gp binary on a 950MHz Solaris machine with > 64GB of RAM. The initial stack was 16GB. The largest the process > grew in the memory was 8GB. The size of the output is 500MB. The > total runtime was 12hours. > > All those are huge numbers. Most people don't have 64GB RAM 64bit > machines at their disposal. For once, the bottleneck is not a > runtime complexity of algorithm, but hardware limitations due to > the implementation. > > Any comments, Bill? :) That great, but you did not beat my record a sfar as degree is considered! My record was made with a 1Gb stack on 1GHz pentium III. Here the entry: Degree:336 Time:13h 43mn Size of result:2581 kb Polynomial:polresultant(x^28-2,subst(polcyclo(28),x,(a-2*x)*x^27/2))*2^12 What is the galois group of your polynomial (use galoisexport and GAP, galoisidentify does not handle degree 324) ? Did you used GMP ? I was not able to find a larger centerless Galois group such that galoisinit would finish and that exist a very sparse polynomial with this Galois group. Cheers, Bill.