I get this using j602. It seems to be correct. 2^63 9.22337e18
2^63x 9223372036854775808 9223372036854775808 9.22337e18 9223372036854775808x 9223372036854775808 Den 21:23 mandag den 26. maj 2014 skrev Raul Miller <[email protected]>: > > >I'm not sure that execution time is a significant bottleneck here. > >If it is, though, I don't think you can get much faster than: > 10000 timespacex '9223372036854775807' >7.18584e_7 1408 > >That said, Henry's approach is about the same speed: > 10000 timespacex '33 b.~_1' >7.46583e_7 1920 > >And if what you want is platform specific (different on 32 bit J from 64 >bit J), Henry's approach would probably be the right way. > >That said, I still like this: > 10000 timespacex '#.63#1' >7.71728e_7 1664 > >Maybe I'm just a sucker for polynomial representations? > >Thanks, > >-- >Raul > > > >On Mon, May 26, 2014 at 3:07 PM, 'Pascal Jasmin' via Programming < >[email protected]> wrote: > >> The 2 fastest versions I've found on my computer: >> >> 100 timespacex '( + <: ) */ +:@:*:^:2 ] 1024 16' >> 3.4112e_6 4352 >> >> 100 timespacex '(+ <:) +:^:14 *:^:4 ] 8 ' >> 5.5744e_6 3072 >> >> >> The &. x: is obviously much more generic and practical for generating >> "medium" sized numbers. >> >> 100 timespacex ' 2 <: &. x:@^ 63 ' >> 8.064e_6 5632 >> >> >> The importance of all this, btw, is that there is a significant size >> penalty to storing extended integers, as well as a time/space compromise in >> working with them. >> >> >> >> ----- Original Message ----- >> From: 'Pascal Jasmin' via Programming <[email protected]> >> To: "[email protected]" <[email protected]> >> Cc: >> Sent: Monday, May 26, 2014 2:35:14 PM >> Subject: Re: [Jprogramming] 2^63 >> >> Might this be the fastest way of getting 2^63-1, without x: ? >> >> (<: + ] ) +:^:14 *:^:4 ] 8 >> 9223372036854775807 >> >> worth noting: >> >> +:^:62 ] 2 >> 9.22337e18 >> +:^:61 ] 2 >> 4611686018427387904 >> >> 2 <: &. x:@^ 63 >> 9223372036854775807 >> >> >> --- >> actually this is probably best: >> >> 2 <: &. x:@^ 63 >> 9223372036854775807 >> 3!:0 ] 2 <: &. x:@^ 63 >> 4 >> >> >> >> >> ----- Original Message ----- >> From: Raul Miller <[email protected]> >> To: Programming forum <[email protected]> >> Cc: >> Sent: Monday, May 26, 2014 2:02:01 PM >> Subject: Re: [Jprogramming] 2^63 >> >> Here's an interesting bug (I can't call this kind of issue a feature if >> it's not documented in the dictionary, can I?): >> >> 9223372036854775809 >> 9223372036854775807 >> >> (And that's probably more important than the "using ^" issue.) >> >> Thanks, >> >> -- >> Raul >> >> >> >> >> >> >> On Mon, May 26, 2014 at 1:55 PM, 'Pascal Jasmin' via Programming < >> [email protected]> wrote: >> >> > is there a way to get ^ to make a 64bit number without it being extended >> > precision? I guess an efficient alternative to ^ if that is not >> possible: >> > >> > 2^63 >> > 9.22337e18 >> > 2^63x >> > 9223372036854775808 >> > 9223372036854775808 >> > 9223372036854775807 >> > >> > Note that the last line is probably a problem. The answer is the largest >> > non extended integer, but still unwelcome change from the input. >> > >> > 9223372036854775808-1 >> > 9223372036854775806 >> > 9223372036854775809-1 >> > 9223372036854775806 >> > >> > I guess this works >> > >> > (<: + ] ) 4611686018427387904 >> > NB. 2^62x >> > 9223372036854775807 >> > >> > ---------------------------------------------------------------------- >> > For information about J forums see http://www.jsoftware.com/forums.htm > >> >> >> >> > >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm >> >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm >> >---------------------------------------------------------------------- >For information about J forums see http://www.jsoftware.com/forums.htm > > > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
