Ed If you expand the Extended Integers section (below by bob), you will
see a link to an essay by Roger on 'Extended Precision Functions'. There
is a Square Root verb.
NB. long rational result may exceed line length
sqrt 1x + *: 999999999x
1249999998750000000625000000625000000468750000156249999765624999453r1250000000000000000000000000000000000000000000000000000000
sqrt *: 999999999x
999999999
~ Gilles
Le 2022-04-21 à 14:50, 'robert therriault' via Programming a écrit :
Gilles,
In Nuvoc the extended constant notation can be found here
https://code.jsoftware.com/wiki/Vocabulary/Constants#Extended_Integers
Having said that, it is hidden pretty well and most of its references are
previous documentation on the jsoftware site. There is certainly work to be
done on the wiki!
Cheers, bob
On Apr 21, 2022, at 11:44, Gilles Kirouac <g1...@myriade.ca> wrote:
Ed
You seem unaware of the extended precision constant notation:
"digits with a trailing x denote an extended precision integer"
https://www.jsoftware.com/help/dictionary/dcons.htm
[Where is the equivalent in NuVoc?]
I would rather write
1x + *: 999999999x
999999998000000002
~ Gilles
Le 2022-04-21 à 12:51, Henry Rich a écrit :
3!:0 %: x: 1 + x: *: x: 999999999
8
The square root cannot be represented exactly.
Henry Rich
On 4/21/2022 12:43 PM, Ed Gottsman wrote:
Hello.
I’m working on the Project Euler “Diophantine equation” problem (#66) and using
J’s extended precision facilities. I’ve run into behavior that confuses me.
Boiled down (and overusing x: just to be sure):
x: %: x: 1 + x: *: x: 999999999
999999999
That is (if my syntax is right), the square root of (one plus the square of a
really large n) is n. I’m apparently misunderstanding something about extended
precision. I’ve tried it with a variety of uses of x: but to no avail, and as
I read the x: documentation…this is an odd result.
Any help would be much appreciated.
(J901 on iPadOS, for which sincere kudos to Ian Clark.)
Many thanks.
Ed
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