Just as a general tactic, one could run the
same problem on commercial macsyma and Maxima
and trace all functions that seem to matter.
The first time a function returns a different answer
suggests a place where the bug may exist.
I have done this with integrate (3^log(x),x).
See http://www.cs.berkeley.edu/~fateman/temp/sin-trace.txt
Raymond Toy wrote:
>>>>>>"Dylan" == Dylan Thurston <dpt@math.harvard.edu> writes:
>>>>>>
>
> Dylan> On Mon, Apr 15, 2002 at 10:04:39AM +0200, Juan Pablo Hierro ?lvarez wrote:
> >> Recently, there has been a bug announced in this list. Basically, maxima
> >> failed to integrate properly expresions of the type:
> >> integrate(3^log(x), x);
> >> It produced an erroneous result, which is worst than not producing result at
> >> all. The reason is just it tries to use the sin algorithm to evaluate the
> >> integral instead of the risch algorithm, which is more general but produces
> >> results which are harder to simplify.
> >>
> >> One quick hack to test this could be to type
> >> :lisp(push '%risch nounl)
> >> before evaluating such integral ...
>
> Dylan> Surely the correct fix is to make sure that the sin algorithm does not
> Dylan> return incorrect results, and then if that algorithm fails try the risch
> Dylan> algorithm?
>
> I agree. Doesn't Wolfgang Jenkner's patch correct the problem? I
> haven't tried it out yet.
>
> Ray
> _______________________________________________
> Maxima mailing list
> Maxima@www.math.utexas.edu
> http://www.math.utexas.edu/mailman/listinfo/maxima
>