Hi,
On Thu, Jul 26, 2012 at 7:40 PM, robin hankin <hankin.ro...@gmail.com> wrote:
> I am trying to generate random numbers and am running into roundoff
> problems:
>
> RealDistribution('uniform', [1,1+1/10^16]).get_random_element()-1
>
> This returns zero every time for me, something that is almost surely wrong.
> I would expect a number chosen from the interval (0,1e-16).
>
> How do I make sage do what I want?
Does this help?
sage: R = RealField(100)
sage: R.random_element(1, 1+1/10^16)
1.0000000000000000745276341034
sage: R.random_element(1, 1+1/10^16)
1.0000000000000000899962307929
and so on. Note that if you try to use RR (which is the same as
RealField(53)) you run into the same precision/roundoff problem as you
had before. Hence the need to increase the working precision.
Also note that R.random_element() can only do uniform distribution, so
if you were hoping for something fancier this won't help.
--
Best,
Alex
--
Alex Ghitza -- Lecturer in Mathematics -- The University of Melbourne
http://aghitza.org
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