time '<: 2x pow 43112609' took about 15 hours.
----- Original Message Follows ----- From: Roger Hui <[email protected]> To: Programming forum <[email protected]> Subject: Re: [Jprogramming] Mersenne Prime initialization. Date: Thu, 09 Apr 2009 18:45:58 -0700 >The problem is that multiplication of extended precision >numbers in J is slow (quadratic). > > > >----- Original Message ----- >From: [email protected] >Date: Thursday, April 9, 2009 18:15 >Subject: Re: [Jprogramming] Mersenne Prime initialization. >To: Programming forum <[email protected]> > >> >> I looked over the essay by roger hui and the: >> >> pow=: 4 : '*/ *~^:(I.|.#:y) x' >> >> works ok. >> >> Regreatably, >> >> time '<: 2x pow 1257787' NB. takes ~41.0 sec >> >> I will try:: >> >> time '<: 2x pow 43112609' >> >> overnight and see what it takes. >> >> ----- Original Message Follows ----- >> From: Aai <[email protected]> >> To: Programming forum <[email protected]> >> Subject: Re: [Jprogramming] Mersenne Prime >> initialization. Date: Thu, 09 Apr 2009 20:18:24 +0200 >> >> >Sorry, another try: >> > >> >http://www.jsoftware.com/jwiki/Essays/Repeated_Squaring >> > >> > >> >-- >> >=@@i >----------------------------------------------------------- >----------- For information about J forums see >http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
