On 10/26/07, Jason Grout <[EMAIL PROTECTED]> wrote:
>
> I'm trying to numerically solve a system of equations. Currently I have:
>
> sage: var('x y p q')
> sage: eq1 = p+q==9
> sage: eq2 = q*y+p*x==-6
> sage: eq3 = q*y^2+p*x^2==24
> sage: solve([eq1,eq2,eq3,p==1],p,q,x,y)
> [[p == 3, q == 6, x == (-2*sqrt(10) - 2)/3, y == (sqrt(2)*sqrt(5) -
> 2)/3], [p == 3, q == 6, x == (2*sqrt(10) - 2)/3, y == (-sqrt(2)*sqrt(5)
> - 2)/3]]
>
> I'd like the answer to be a numeric approximation, though (i.e.,
> x==-2.77485177345). I can't find any other solving routines other than
> the symbolic one, though. Is there a way to numerically approximate the
> solution, other than going through each solution and calling n() on the
> left side of each symbolic expression?
Examples using numpy and octave are give in the constructions cookbook:
http://www.sagemath.org/doc/html/const/node35.html
>
> Thanks,
>
> Jason
>
> P.S. On a different note, my real code has something like:
>
> sage: [solve([eq1,eq2,eq3,p==i],p,q,x,y) for i in [1..4]]
>
> which produces a nested list. Is there a way to flatten the list by one
> or two levels, but not flatten it all the way? Something like:
>
> sage: flatten([[[1,2],[3,4]],[[5,6],[7,8]]],1)
> [[1,2],[3,4],[5,6],[7,8]]
>
>
> >
>
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