On 05/15/2010 04:51 AM, Dieter Kaiser wrote:
> Am Samstag, den 15.05.2010, 02:33 -0600 schrieb Robert Dodier:
>
>> On 5/14/10, pbowyer at olynet.com<pbowyer at olynet.com> wrote:
>>
>>
>>> As you can see from the output, I have an extra term involving p[0] for the
>>> FD[i](3,0) function outputs that does not show up if I manually do the
>>> calculation. Am I doing something incorrectly, or is there a problem
>>> with Maxima?
>>>
>> Yes, it's a bug. Here is a simpler example:
>>
>> 'sum(0^i, i, 0, n);
>> => 0
>>
>> Depending on what you think is the value of 0^0, that should either
>> trigger an error (since Maxima by default believes 0^0 is undefined)
>> or 1 (pretty much everyone else in the world).
>>
>> In the above example, Maxima has assumed that 0^i => 0 without
>> looking at the possible values of i. Here is an even simpler example.
>>
>> 0^i;
>> => 0
>>
>> assume (i>= 0);
>> 0^i;
>> => 0
>>
>> I claim neither of these should simplify to 0;
>> anyone who believes 0^0 = 1 (and this does seem to be quite
>> a lot of people) should agree.
>>
>> By the way, you're more likely to get people to look at your
>> problem if you say "Here is X and here is Y, I thought they
>> should be the same but they're not" as opposed to "Here are
>> 10 different things, two of which are not equal."
>>
> With revision 1.97 of simp.lisp we had a patch to handle the expression
> 0^a more carefully and more complete.
>
> With revision 1.99 of simp.lisp this patch has been reverted in parts.
> Especially, 0^a again simplifies to 0. This had to be done because the
> routines of simptimes can not handle unsimplified 0^a expressions.
>
> Therefore, in a next step we have to improve the routines of simptimes
> to handle unsimplified 0^a expressions.
>
> Dieter Kaiser
>
>
>
>
Dieter Kaiser:
Is there a file I can download and include in my revision of Maxima that
will solve the problem with sum in case I need to use it for something
else? If there is, tell me where (and how) to get it and how to install
it. Would a different release of Maxima (I'm using 5.20.1) be more
appropriate?
Robert Dodier:
I apologize for the length of my original message. I didn't think to try
to a simpler example and so I just sent information relative to my
problem. I'll try to be less verbose if I have another problem that
needs attention.
Thank you both for the quick response to my problem.
Paul Bowyer