wow, huff huff: let's move this to chart where it belongs hereafter.
Sadly, you missed, obliviously, the obvious,
which Roger Hui already explained succinctly (and correctly); and
I noted an apostate opinion:
Either you represent mathematical transcendentals precisely or you do not.
As defined (Roger pointed out),
it is not perfectly represented or carried in calculations:
this is not an error, it is as defined.
My response pointed out in sardonically humorous
(whether you like it or not being irrelevant)
and brief
terms that
a) I prefer exact representation. Others seem to as well.
But that is not the current J design or systematic philosophy on this
topic (and others):
given the immense value of this incredible gem of huge power in
a small program
(compared to almost any other array processor or math
package)
called J
I would love to see the choice made to go in that direction:
but it is not a trivial one.
b) There is no systematic way around this other than do or do not; otherwise
c) you are going to be involved with detailed numerical analysis
(error propagation and estimates), unless
d) you do the exact precision your self
e) which would require setting up a redefinition
basically overlaying the entire interpreter
of most J functors to be systematic (not trivial) or
f) going through a lot of perambulations in discourse
to come to a half baked method of handling it;
albeit you will learn a lot on that path, too, of math ...
g) which I noted was somewhat off course (hyperbolically so), and on a
tangent (sic) to
the original design imperatives (I perceive) inherent in the best of
J...
h) If you are interested in a data structure to do this, see the J archives
on CRT
and recursive polyad representation; it will not solve the problem:
but the reason I would like J to try it ...
is because of the sheer mass of smarts present in this Forum.
I would give more details and go further into your particular discussion,
but you do not seem to want it;
and I am handling medically stimulated diabetes and whether I will be on the
street tomorrow: sorry.
Maybe later tonight offline I can come up with a solution for you ...
Gott to try to seel some asets to make room rent tomorrow.
On 12/5/06, Richard Donovan <[EMAIL PROTECTED]> wrote:
I nominate this reply, and a previous one-liner by the same author
( " This is not a bug " ) as two of the most uninformative and unhelpful
messages I have ever seen posted to this normally informative and
very helpful forum!
>From: Roger Hui <[EMAIL PROTECTED]>
>Reply-To: General forum <[email protected]>
>To: General forum <[email protected]>
>Subject: Re: [Jgeneral] Bug? Sin of pi.
>Date: Fri, 01 Dec 2006 11:06:26 -0800
>
>Changes in the C library? Vagaries in the CPU?
>Phase of the moon?
>
>
>
>----- Original Message -----
>From: Joey K Tuttle <[EMAIL PROTECTED]>
>Date: Friday, December 1, 2006 10:55 am
>Subject: Re: [Jgeneral] Bug? Sin of pi.
>
> > At 10:32 -0800 2006/12/01, Roger Hui wrote:
> > >Because
> > >
> > > 1p1 - 3.141592653589793
> > >0
> > >
> > But, as was pointed out -
> >
> > 9!:14 ''
> > 4.05/2001-05-16/11:30
> > 1 o. 1p1
> > 0
> > 1p1 - 3.141592653589793
> > 0
> >
> > I think the question is, what has caused the shift?
> >
> > 9!:14 ''
> > j504/2005-03-16/15:30
> > 1 o. 1p1
> > 1.22461e_16
> > 1p1 - 3.141592653589793
> > 0
>
>
>----------------------------------------------------------------------
>For information about J forums see http://www.jsoftware.com/forums.htm
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