Hi, On Thu, Nov 18, 2010 at 11:51:59AM -0800, Filip Dominec wrote: > > > On Nov 18, 7:02 pm, Mateusz Paprocki <matt...@gmail.com> wrote: > > it can be easily extended > > to support rational functions and absolute values (somewhere I have > > preliminary code for this). > > Cool. Right now I am using sympy to solve some calculations for > geometrical optics. These problems boiled down to a system of rational > equations with several variables. However, there are also several > constraints which would be handled the most efficient way if I could > simply calculate intersection of all the intervals for which the > inequalities hold. > > This is my motivation to use the inequality solver. I would be happy > if I could get the fresh version from git, test it on a real problem > and report how it works. > > > > I think it shouldn't be very hard to write a function for > > converting relational to interval form (where it makes sense). > > I expect it would not be hard, but I have not oriented in the code yet > to try it myself.
Actually, it is possible to get intervals, you just need to set
'relational' flag to False, e.g.:
In [1]: ieqs = [(x-1)*(x-2)*(x-3) >= 0, (x+1)*(x-2) >= 0]
In [2]: solve(ieqs + [Assume(x, Q.real)], x, relational=False)
Out[2]: [{2}, [3, ∞)]
As you can see solve() can handle systems of inequalities (allowed
operators are ==, !=, >, >=, <, <=). The inequality solver is run
when at least one relational operator is encountered. If you set
relational=False together with a complex variable, then you will
get the result in relational form anyway.
> Filip
>
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Mateusz
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