Peter,
I agree completely with Robert Dodier's "PS" -- we can't really give you
useful advice without that background. Even if we manage to help you
without that, I find it presumptuous on your part to just dump a source
file in our laps and say "fix my problem".
For example, it may be that you can solve your problem by calculating with
truncated Taylor series, something like this:
term1: taylor(expr1,x,0,5)$
term2: taylor(expr2,x,0,5)$
term1*term2;
instead of
taylor(expr1*expr2,x,0,5)$
It may be that substituting numerical values for your parameters earlier in
the process makes sense.
It may be that you should really be using numerical techniques and not
symbolic for the whole calculation.
It may be that Robert's suggestion of calculating with a formal Taylor
series is best.
*etc.*
I really don't know, and I'm not going to try to reverse-engineer your code
to see if some other approach is more appropriate.
-s
On Sun, Dec 16, 2012 at 4:58 PM, Robert Dodier <robert.dodier at gmail.com>wrote:
> On 2012-12-16, =?utf-8?Q?foelsche at sbcglobal.net?= <foelsche at sbcglobal.net>
> wrote:
>
> > Can anybody tell me, why this maxima source is not finishing....
>
> Well, the problem is that the expressions you are working with are
> enormous -- one of them has 100,000 terms or something like that. Maxima
> is doing its best but there may not be enough time & memory to finish
> the job.
>
> As to the reason why the expressions are so big -- it's not clear if
> it's inherent in the problem, or perhaps Maxima's heuristics for
> simplification are actually working towards bigger & bigger expressions,
> or something else.
>
> I am working on an approach which keeps the expressions relatively
> small. Basic idea is to construct a formal Taylor series & integrate it,
> then substitute the actual expressions & actual values later. Trying to
> construct the Taylor series seems to massively expand an already-large
> expression ... I'll get back to you later today or tomorrow about it.
>
> best
>
> Robert Dodier
>
> PS. Heroic debugging efforts notwithstanding, it would really help if
> you could indicate what you have tried, what worked, what didn't, what
> you're trying to accomplish, etc.
>
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