BEST NEEDS basic64


BASIC64 myprog beats Maple on Factor bignum!

******************

newgroups: sci.math, comp.sys.acorn.apps

date:  09.03.00  23:46  pm. nzdt


myfile > Bas6 v Mapl.


 progm--    fin.soc.acorncpusr.donWn994/2.pi.facthcff. byte/zeta4

don mcdonald,    18.07.99  12:30 PM. 16:00. 22:25


Examples : 1E15-1,  1E18/999 999,  2^37-1,  2^31-1

2^33-9 prime,  6763*10627*29947 Maple IsPrime

1E10-1, 1E11-1,  1E12-1, 1E14-1, 2^32+1 Euler, 13^10+1

1E13-1, 1E16-1,  100 895 598 169 Mersenne

10 662 526 601,  15 527 402 881.



factor 5 byte integer, max 2^40  gets most factors .TEST bugs

enter no. / expression  . Qq/ 0 <CR> = quit  ?195264367847

195264367847 = 195264367847



proc Hhcf(x = 195264367847

  x  > 2 ^31.  slow e.g. minutes.

TRY FOR j = 4999  TO SQRT = 441887.279571385705  STEP 2.

factors ?   x1 =  j*x1 =   417559 *  467633 ***************

   centiseconds = 23430     4 minutes


 You have 10 seconds to press a key.

417559 prime.      centisec = 24461

467633 prime.      centisec = 24492

417559 * 467633


factor 5 byte integer, max 2^40  gets most factors .TEST bugs

enter no. / expression  . Qq/ 0 <CR> = quit  ?1589083027309

1589083027309 = 1589083027309



proc Hhcf(x = 1589083027309

  x  > 2 ^31.  slow e.g. minutes.

TRY FOR j = 4999  TO SQRT = 1260588.36552976328  STEP 2.

factors ?   x1 =  j*x1 =   776057 *  2047637  ******

   centiseconds = 42389     **  7 minutes.


 You have 10 seconds to press a key.

776057 prime.      centisec = 43430

2047637 prime.     centisec = 43496

776057 * 2047637


factor 5 byte integer, max 2^40  gets most factors .TEST bugs

enter no. / expression  . Qq/ 0 <CR> = quit  ?

progm facthcff.   e n d.    CLOSEs * RAM SPOOL

(#####*******

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                  Re: Math web site (mainly Number Theory)

                           Posted by: Dave Rusin

                      Date: 2000/02/29 Group: sci.math

     _________________________________________________________________

                                      

                                      

                 In article <89f1hr$3qm$1@morgoth.sfu.ca>,

                   Erick Bryce Wong <erick@sfu.ca> wrote:

              >Jeremy Boden <jeremy@jboden.demon.co.uk> wrote:

                  >>Erick Bryce Wong <erick@sfu.ca> writes

    >>>BTW, there are cases where Maple takes forever to favor a "tiny"

                                   number

    >>>(try 195264367847 or 1589083027309 in R4 or R5, dunno about R6),

                                   and I

     >>>suspect it really is an infinite loop in the implementation of

                                  ifactor.

                                     >>

                         >>That's rather peculiar!

      >>I've only got Maple R3 and it takes about 1 second on each of

                     >>195264367847 and 1589083027309.

                                     >

   >Yup, R3 didn't have this problem...But if I recall correctly, R3 did

                                  have an

     >equally bad infinite loop in isprime(), which was fixed in R4. I

                                 know, it's

   >hard to imagine an infinite loop in a probablistic primality test...I

                                   don't

    >remember what the specific number was, but it was only around 9-12

                                  digits.

                                      

    I believe it was R3 which would choke on numbers containing 1093 or

     3511 as prime factors; perhaps you can imagine the primality tests

        being (mis)used which would flag those numbers as special...

                                      

       I don't understand why the numbers shown above defeat R4, R5.

                                    dave


Can I factor these on Acorn A4000 myprog

 UK 1993 computer with 2 MB RAM?  RISC OS 3.11

Yes, Apparently.     // don.