My understanding is that SymPy is not able to handle information like
`assume(A<B)`. This has been on our issues list for a while I think.
On Wed, Nov 14, 2012 at 1:58 PM, Simon Clift <sscl...@gmail.com> wrote:
> Digging. I'm looking to hack something in to support symbolic intervals
> and need some advice, please.
>
> I'm getting my problem laid out as an intersection, but I'm hitting a
> problem performing the calculation symbolically. If I have
>
> A,B,C,D = symbols( ( "A", "B", "C", "D" ), real=True )
>
> i_ab = Interval ( A, B )
> i_cd = Interval ( C, D )
>
> i_chk = Intersection( i_ab, i_cd )
>
> then in line 449 of core/sets.py I don't have the is_comparable property.
> I was looking through the core/relational.py code for an operator that
> would allow me to impose a strict ordering, say A < C < B < D (in Maple I
> would use something like assume(A<B) ). Is there an accepted way of
> attaching an is_comparable type operation to the individual Symbol objects,
> say:
>
> A.is_lessthan( C )
>
> which would (say) set
>
> A.is_comparable = True
> A.comparison_dict = { C : '<' }
>
> or something suitably Sympy-compatible? Should I fear combinatoric
> complexity problems evaluating that?
>
> Thanks
> -- Simon
>
>
> On Monday, 12 November 2012 15:15:52 UTC-5, Matthew wrote:
>>
>> If you do go digging around in the code I'd probably suggest working with
>> sympy.core.sets rather than sympy.stats. sympy.core.sets is better
>> organized and has a much lower entry barrier.
>>
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