When I got Roger's reply - I read it as "I don't know..."
Quite an unusual response about changes in J results!
Actually, I ruled out the Phase of the moon, since both
experiments were performed quite close in time - and vagaries
in the CPU for the reason that both results were from same
machine, only seconds apart (and were reproducible). That ony
left "Changes in the C library".
I am a bit surprised that results from C library routines would
lead to reduced accuracy in a newer release of J... I thought
perhaps a "special check" had been removed, but surely Roger
would have said that. Just to be clear - my expectations are
not that "numerical results should conform ..." --- merely
surprise that the result of 1 o. 1p1 changed between releases
of J.
Other than Roger's rather flip/dismissive remarks, no one else
seems to wonder about that... That also surprises me.
- joey
At 10:48 -0400 2006/12/05, ramacd wrote:
Folks;
Although I concur with the assessment of the level of helpfulness, the issue
seems to be how one responds to an impossibly high expectation, namely that
machine-based numerical results should conform to mathematical identities
( 0 = sin k * pi, in this case).
Perhaps the response was too obvious, like "the fact that the perpetual
motion machine stopped is not a bug," would be.
----- Original Message -----
From: "Richard Donovan" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, December 05, 2006 6:59 AM
Subject: Re: [Jgeneral] Bug? Sin of pi.
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
>
>
>----------------------------------------------------------------------
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