* bug#9103: 23.3.50; random* from cl does not support the whole range of integers
@ 2011-07-17 4:03 Leo
2011-07-18 21:56 ` Glenn Morris
2020-11-19 5:19 ` Stefan Kangas
0 siblings, 2 replies; 9+ messages in thread
From: Leo @ 2011-07-17 4:03 UTC (permalink / raw)
To: 9103
As far as I can see, (random* most-positive-fixnum) only returns a 32bit
integer on 64bit Emacs. This might be an oversight given the age of
cl.el.
Leo
^ permalink raw reply [flat|nested] 9+ messages in thread
* bug#9103: 23.3.50; random* from cl does not support the whole range of integers
2011-07-17 4:03 bug#9103: 23.3.50; random* from cl does not support the whole range of integers Leo
@ 2011-07-18 21:56 ` Glenn Morris
2011-07-18 21:58 ` Glenn Morris
2020-11-19 5:19 ` Stefan Kangas
1 sibling, 1 reply; 9+ messages in thread
From: Glenn Morris @ 2011-07-18 21:56 UTC (permalink / raw)
To: Leo; +Cc: 9103
Leo wrote:
> As far as I can see, (random* most-positive-fixnum) only returns a 32bit
> integer on 64bit Emacs.
Why does random* even need to exist? What can it do that plain random
cannot?
^ permalink raw reply [flat|nested] 9+ messages in thread
* bug#9103: 23.3.50; random* from cl does not support the whole range of integers
2011-07-18 21:56 ` Glenn Morris
@ 2011-07-18 21:58 ` Glenn Morris
2011-07-19 1:21 ` Leo
2011-09-11 3:20 ` Lars Magne Ingebrigtsen
0 siblings, 2 replies; 9+ messages in thread
From: Glenn Morris @ 2011-07-18 21:58 UTC (permalink / raw)
To: Leo; +Cc: 9103
Glenn Morris wrote:
> Why does random* even need to exist? What can it do that plain random
> cannot?
...non-integer results, it seems.
^ permalink raw reply [flat|nested] 9+ messages in thread
* bug#9103: 23.3.50; random* from cl does not support the whole range of integers
2011-07-18 21:58 ` Glenn Morris
@ 2011-07-19 1:21 ` Leo
2011-07-19 1:28 ` Juanma Barranquero
2011-09-11 3:20 ` Lars Magne Ingebrigtsen
1 sibling, 1 reply; 9+ messages in thread
From: Leo @ 2011-07-19 1:21 UTC (permalink / raw)
To: Glenn Morris; +Cc: 9103
On 2011-07-19 05:58 +0800, Glenn Morris wrote:
> Glenn Morris wrote:
>
>> Why does random* even need to exist? What can it do that plain random
>> cannot?
>
> ...non-integer results, it seems.
We need to extend plain random to support random-states. I plan to do it
once the random module in gnulib is usable.
Another option is to use Mersenne Twister PRNG, which I have in my local
tree (patch: http://paste.pocoo.org/show/ZYhLUPeXlkj405100KX4/). The
files mt19937.[ch] are from its authors'. Do you know if that can be
included in Emacs?
Leo
^ permalink raw reply [flat|nested] 9+ messages in thread
* bug#9103: 23.3.50; random* from cl does not support the whole range of integers
2011-07-18 21:58 ` Glenn Morris
2011-07-19 1:21 ` Leo
@ 2011-09-11 3:20 ` Lars Magne Ingebrigtsen
2011-09-11 7:44 ` Andreas Schwab
2021-10-22 15:58 ` Stefan Kangas
1 sibling, 2 replies; 9+ messages in thread
From: Lars Magne Ingebrigtsen @ 2011-09-11 3:20 UTC (permalink / raw)
To: Glenn Morris; +Cc: Leo, 9103
Glenn Morris <rgm@gnu.org> writes:
> Glenn Morris wrote:
>
>> Why does random* even need to exist? What can it do that plain random
>> cannot?
>
> ...non-integer results, it seems.
`random*' ends with
(* (/ n '8388608e0) lim)
if LIM isn't an integer. Anybody willing to hazard a guess why
8388608.0 was chosen?
And would it make sense to just replace it all with a call to `random',
and then make it into a floating point if it floats?
--
(domestic pets only, the antidote for overdose, milk.)
bloggy blog http://lars.ingebrigtsen.no/
^ permalink raw reply [flat|nested] 9+ messages in thread
* bug#9103: 23.3.50; random* from cl does not support the whole range of integers
2011-09-11 3:20 ` Lars Magne Ingebrigtsen
@ 2011-09-11 7:44 ` Andreas Schwab
2021-10-22 15:58 ` Stefan Kangas
1 sibling, 0 replies; 9+ messages in thread
From: Andreas Schwab @ 2011-09-11 7:44 UTC (permalink / raw)
To: Lars Magne Ingebrigtsen; +Cc: Leo, 9103
Lars Magne Ingebrigtsen <larsi@gnus.org> writes:
> `random*' ends with
>
> (* (/ n '8388608e0) lim)
>
> if LIM isn't an integer. Anybody willing to hazard a guess why
> 8388608.0 was chosen?
Because that's the range of n.
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
^ permalink raw reply [flat|nested] 9+ messages in thread
* bug#9103: 23.3.50; random* from cl does not support the whole range of integers
2011-09-11 3:20 ` Lars Magne Ingebrigtsen
2011-09-11 7:44 ` Andreas Schwab
@ 2021-10-22 15:58 ` Stefan Kangas
1 sibling, 0 replies; 9+ messages in thread
From: Stefan Kangas @ 2021-10-22 15:58 UTC (permalink / raw)
To: Lars Magne Ingebrigtsen; +Cc: Glenn Morris, Leo, 9103
Lars Magne Ingebrigtsen <larsi@gnus.org> writes:
>> Glenn Morris wrote:
>>
>>> Why does random* even need to exist? What can it do that plain random
>>> cannot?
>>
>> ...non-integer results, it seems.
(That's `cl-random' these days.)
> and then make it into a floating point if it floats?
The Common Lisp version of `random' supports float and integer values
depending on what type its argument has. I guess that's what
`cl-random' is based on.
I'm not sure if we can change `random' to do the same. But if there is
a need for random floating point numbers, it does seem unfortunate that
we only have that functionality in CL-Lib.
^ permalink raw reply [flat|nested] 9+ messages in thread
* bug#9103: 23.3.50; random* from cl does not support the whole range of integers
2011-07-17 4:03 bug#9103: 23.3.50; random* from cl does not support the whole range of integers Leo
2011-07-18 21:56 ` Glenn Morris
@ 2020-11-19 5:19 ` Stefan Kangas
1 sibling, 0 replies; 9+ messages in thread
From: Stefan Kangas @ 2020-11-19 5:19 UTC (permalink / raw)
To: Leo; +Cc: 9103
Leo <sdl.web@gmail.com> writes:
> As far as I can see, (random* most-positive-fixnum) only returns a 32bit
> integer on 64bit Emacs. This might be an oversight given the age of
> cl.el.
This seems to be an issue also with cl-random on current master, AFAICT.
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2021-10-22 15:58 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-07-17 4:03 bug#9103: 23.3.50; random* from cl does not support the whole range of integers Leo
2011-07-18 21:56 ` Glenn Morris
2011-07-18 21:58 ` Glenn Morris
2011-07-19 1:21 ` Leo
2011-07-19 1:28 ` Juanma Barranquero
2011-09-11 3:20 ` Lars Magne Ingebrigtsen
2011-09-11 7:44 ` Andreas Schwab
2021-10-22 15:58 ` Stefan Kangas
2020-11-19 5:19 ` Stefan Kangas
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