Karl-Dieter,
Why would you think it sets algexact at all? Barton said "it internally
defaults algexact to true", which I suppose is his non-technical way of
saying that it *binds *it.
Barton is an experienced Maxima developer, and I don't think he'd do
anything as foolish as have a function of his change a global setting.
-s
On Sat, Jun 15, 2013 at 8:58 AM, Karl-Dieter Crisman <kcrisman at gmail.com>wrote:
>
>
>
> On Sat, Jun 15, 2013 at 8:48 AM, Barton Willis <willisb at unk.edu> wrote:
>
>> I changed the source of to_poly_solve.mac so that it internally
>> defaults algexact to true. A user can override the default by appending
>> 'algexact=false to the %solve (or to_poly_solve) argument list. Notice
>> that algexact : false does *not* guarantee a float result
>> (see the user documentation for algexact).
>>
>>
>>
>
> Most importantly, does that set algexact for the whole Maxima session, or
> does it then revert to false? I wouldn't want to mess with Maxima that way
> just for this - we could set the algexact back and forth in our own use of
> to_poly_solve, now that we know this won't have adverse side effects.
>
>
>
>> Example
>>
>> Use default algexact
>>
>> (%i2) %solve(max(1-x^2,2)=x^3,x);
>>
>> (%o2) %union([x = 2^(1/3)],[x = (2^(1/3)*sqrt(3)*%i-2^(1/3))/2],
>> [x = -(2^(1/3)*sqrt(3)*%i+2^(1/3))/2])
>>
>> (%i3) float(%);
>>
>> (%o3) %union([x = 1.259921049894873],
>> [x = 0.5*(2.182247271943443*%i-1.259921049894873)],
>> [x = -0.5*(2.182247271943443*%i+1.259921049894873)])
>>
>> Grumble why the need for expand...
>>
>> (%i4) expand(%);
>>
>> (%o4) %union([x = 1.259921049894873],
>> [x = -1.091123635971721*%i-0.629960524947437],
>> [x = 1.091123635971721*%i-0.629960524947437])
>>
>> Override algexact default:
>>
>> (%i5) %solve(max(1-x^2,2)=x^3,x,'algexact=false);
>>
>> (%o5) %union([x = 1.259921095381759],
>> [x = -1.091123635971721*%i-0.629960524947437],
>> [x = 1.091123635971721*%i-0.629960524947437])
>>
>> Let me guess that the Sage developers will at least need to change some
>> test results. So it goes.
>>
>
> I'm not worried about that! Just wanting to find the most exact answers
> we can with Maxima :-)
>
>
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