Also refine in not mentioned in simplify:
/sympy/simplify$ grep -r refine *
But on the other hand assumptions are mentioned in docstrings but they do
not refer actually to the assumption module:
55 This function will also work fine with assumptions:
56
57 >>> k = Symbol('k', negative=True)
58 >>> fraction(x * y**k)
59 (x, y**(-k))
What is the relation between those. Why both of them exists (assumption.py
and is_something flags)?
On 7 December 2011 20:36, [email protected] <
[email protected]> wrote:
> How should assumptions be used? More precisely why the following code does
> what it does
>
> In [18]: global_assumptions.clear()
>
> In [19]: x = Symbol('x', positive=True)
>
> In [20]: ask(Q.positive(x)) # Why does it return None?
>
> In [21]: x > 0
> Out[21]: True
>
> In [22]: global_assumptions # It's empty but I already declared x as
> positive
> Out[22]: AssumptionsContext()
>
> In [23]: ask(Q.positive(x))
>
> In [24]: global_assumptions.add(Q.positive(x))
>
> In [25]: ask(Q.positive(x))
> Out[25]: True
>
> Why setting a symbol to positive does not create a global assumption? What
> are assumption used for actually when there are all the is_something flags?
>
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