isp.com> writes:
> I've tested on all platforms I know of and confirmed it. The wrong digit
> occurs in the middle of the number. Propagation error would have a bad digit
> near the end, and garbage after that. Here there's a perfect sequence of
> numbers, but with one single digit changed in th
On 5/15/14 3:45 PM, pleasedonts...@isp.com wrote:
Please take a deeper look at my second post. Try the same but this time
set the precision to 4000, 8000 or whatever you need to convince yourself
there's no error propagation, yet there's a 4 in the middle that shouldn't
be there. See for yours
On Sunday, May 4, 2014 6:53:06 AM UTC-4, Mark Dickinson wrote:
> I had a quick look: this isn't a bug - it's just the result of propagation of
>
> the error in "partial" to "final".
>
>
>
> In more detail: we've got a working precision of 2016 significant figures.
> For
>
> any small x, we
On Tue, 29 Apr 2014 19:37:17 -0700, pleasedontspam wrote:
> Hello, I believe I found a bug in the Decimal library. The natural logarithm
> results seem to be off in a certain range, as compared with Wolfram Alpha.
I had a quick look: this isn't a bug - it's just the result of propagation of
the e
On Tuesday, April 29, 2014 11:39:12 PM UTC-4, Steven D'Aprano wrote:
> On Tue, 29 Apr 2014 19:37:17 -0700, pleasedontspam wrote:
>
>
>
> > from decimal import *
>
> > getcontext().prec=2016
>
> > one=Decimal(1)
>
> > number=Decimal('1e-1007')
>
> > partial=(one+number)/(one-number)
>
> > fi
On Tuesday, April 29, 2014 11:39:12 PM UTC-4, Steven D'Aprano wrote:
> On Tue, 29 Apr 2014 19:37:17 -0700, pleasedontspam wrote:
>
>
>
> > from decimal import *
>
> > getcontext().prec=2016
>
> > one=Decimal(1)
>
> > number=Decimal('1e-1007')
>
> > partial=(one+number)/(one-number)
>
> > fi
pleasedonts...@isp.com wrote:
I compared the results with wolfram Alpha, and
also with an open source arbitrary precision calculator, which matches Alpha
results.
Decimal is *not* an arbitrary precision data type, so you
can't expect exact results from it. You can set the precision
to be very l
On Tue, 29 Apr 2014 19:37:17 -0700, pleasedontspam wrote:
> from decimal import *
> getcontext().prec=2016
> one=Decimal(1)
> number=Decimal('1e-1007')
> partial=(one+number)/(one-number)
> final.ln()
What's final? Did you mean partial?
When I try it in Python 3.3, I get:
py> from decimal impor
