Oops, removing inexact arithmetic does cause errors.
On May 24, 8:41 pm, Matthew <mrock...@gmail.com> wrote:
> Cool. I'm going ahead with the changes. I'm currently blocking on the
> reduce_poly_inequalities function.
> It assumes that it's dealing with a list of Intervals which it then
> will return or turn into a relational. I have generalized this
> as_relational process to all sets but am having difficulty when it
> needs to create sets with inexact arithmetic.
>
> This python file has a special interval_evalf function used just for
> this one case which makes new intervals with evaluated numbers rather
> than exact ones. i.e.
> Interval(interval.left.evalf(), interval.right.evalf() )
>
> I don't want to make a union_evalf , finiteset_evalf, etc... but if I
> push this into a ._eval_evalf method then I'll end up overwriting the
> existing Interval._eval_evalf method which seems to be creating
> multiprecision intervals which are used for some other purpose.
>
> I guess I'm not sure exactly why the inexact bits are needed. When I
> remove this functionality it doesn't seem to break any tests. I'm not
> knowledgeable enough to know if this is important or not.
>
> Thoughts?
>
> Also, unrelated question. There are some tests which fail when I run
> bin/test but which pass when I run them from ipython or isympy. I
> suspect this is just something screwy with how I have things set up.
> Sound familiar to anyone?
>
> -Matt
>
> On May 24, 7:50 pm, Mateusz Paprocki <matt...@gmail.com> wrote:
>
>
>
>
>
>
>
> > Hi,
>
> > On 24 May 2011 17:42, Aaron S. Meurer <asmeu...@gmail.com> wrote:
>
> > > Hi.
>
> > > On May 24, 2011, at 5:50 PM, Matthew Rocklin wrote:
>
> > > > Hi Everyone,
>
> > > > I'm revamping Sets a bit as a precursor to my GSoC project. The first
> > > part of this is creating a FiniteSet object to go along with Intervals
> > > (like
> > > (0, 1] ) and Unions (like [-1,0) U (0, 1] ).
>
> > > > I changed the default behavior of Interval(1,1) (interval from 1 to 1
> > > inclusive, i.e. [1, 1] ) to be just the FiniteSet {1} .
>
> > > > Unfortunately it appears that Interval(a,a) has been used extensively in
> > > the inequalities module for things like
>
> > > > reduce_poly_inequalities([[Eq(x**2, 1)]], x, relational=False) ==
> > > [Interval(-1,-1), Interval(1, 1)]
>
> > > > My code changes the result to the FiniteSet {-1, 1} which I think makes
> > > more sense. I'm a little uneasy about going in and changing this much in
> > > modules with which I have little experience. Are people ok with this? Is
> > > there anyone I should converse with while dealing with this particular
> > > problem? (someone involved in inequalities)
>
> > > > Best,
> > > > -Matt
>
> > > So first off, you should run the tests. If they still pass, then it means
> > > that the code still works. This is why we have tests.
>
> > > In this particular case, I think it's fine. That probably would have used
> > > a finite set anyway, if they had existed at the time. Mateusz wrote this
> > > code, so he could tell you more. But I personally am +1 to making
> > > Interval(a, a) return FiniteSet(a).
>
> > That should work fine, but as Aaron said, change this run tests and see what
> > it the outcome.
>
> > > Aaron Meurer
>
> > > --
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>
> > Mateusz
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