On Fri, Jan 9, 2009 at 9:05 AM, William Stein <[email protected]> wrote:
> On Fri, Jan 9, 2009 at 9:01 AM, Robert Dodier <[email protected]> wrote:
>>
>> On Jan 9, 6:51 am, Slava <[email protected]> wrote:
>>
>>> I`m trying to solve such simple system of equations: [sqrt(x) == 1, x
>>> == y],
>>> so I type:
>>>
>>> x,y = var('x,y');
>>> solve([sqrt(x) == 1, x == y], x, y);
>>>
>>> the answer is: []
>>
>> If I understand correctly, Sage punts to Maxima to solve equations.
>> Maxima's built-in solver is not too strong. There is an add-on package
>> which can solve equations which contain radicals. Dunno how to call
>> it from Sage, but in Maxima itself it's like this:
>>
>> load (topoly_solver);
>> to_poly_solve ([sqrt(x) = 1, x = y], [x, y]);
>> => [[x = 1, y = 1]]
>>
>> Maybe at some point in the not-too-distant future, the built-in
>> solver would call to_poly_solve automatically ....
Robert,
Is there any reason not to just *always* use topoly_solver? I.e.,
maybe Sage's solve should
just 100% always only call topoly_solver. What do you think?
William
>
> That would be nice. Here's doing the above in sage:
>
> sage: x,y=var('x,y')
> sage: v = [sqrt(x)==1, x==y]
> sage: w = maxima(v)
> sage: maxima.load('topoly_solver')
> sage: w.to_poly_solve([x,y])
> [[x=1,y=1]]
>
> There's currently no simple code in sage to turn the output of
> to_poly_solve into native sage objects.
>
> William
>
--
William Stein
Associate Professor of Mathematics
University of Washington
http://wstein.org
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