On 1/10/2013 12:11 PM, Robert Dodier wrote:
> On 2013-09-30, Wilhelm Haager <wilhelm.haager at htlstp.ac.at> wrote:
>
>> I think, a new bug has been introduced in Maxima 5.31.1-1:
>> realroots hangs when trying to calculate the real roots
>> even of a simple polynomial:
>>
>> (%i1) p:x^3+2*x^2-2*x-1;
>> (%o1) x^3+2*x^2-2*x-1
>> (%i2) realroots(p); .... HANGUP!
> The problem is specific to GCL (works as expected with other Lisps).
> Problem seems to be that the global variable 'rootsepsilon' is zero
> while it should be nonzero. Try this: realroots(p, 1e-7); or
> realroots(p), rootsepsilon=1e-7; Does it work OK?
Excellent remote diagnosis
(%i2) p:x^3+2*x^2-2*x-1$
(%i3) realroots(p,1e-7);
(%o3) [x = -87846643/33554432,x = -12816653/33554432,x = 1]
(%i4) rootsepsilon;
(%o4) 0.0
> I don't know what changed between 5.30 and 5.31 to affect it.
Perhaps due to gcl version upgrade to 2.6.8 release