|Bill Allombert on Mon, 11 Jun 2012 14:45:19 +0200|
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|Re: Set prime limit|
On Mon, Jun 11, 2012 at 02:25:35PM +0200, Jean-Marie Madiot wrote: > Dear all, > > I know that I can set GP stack size both when launching gp and at runtime: > > $ gp -s 12345678 > ? allocatemem(12345678) You can also do default(parisize,12345678) > I don't know if it's a good idea, but it's quite handy. > > 1) Is it possible to do the same for the prime limit (i.e. to run the > sieve at runtime)? Yes, use default(primelimit,12345678) > 2) Is it possible to access the prime limit at runtime? default(primelimit) > 3) Is it possible to access the stack size at runtime? (this is just > by curiosity though) default(parisize) > 4) Would it be possible to have a forprime() function that goes beyond > the prime limit? We added this feature in the development branch, so now you can do: ? forprime(p=2^100,,if(p%123==1,return(p))) %2 = 1267650600228229401496703208451 > I have workaround that does (4), but I need to enter the prime limit > manually (then beyond the prime limit uses the slower isprime()) It is advised to use nextprime instead of isprime for this purpose, this is slightly faster. Cheers, Bill.