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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